Why is there a growing preoccupation with particle size?
It’s because particle size can alter the efficacy (e.g., bioavailability) and safety profile (e.g., toxicity) of a compound.
Complex particle sizing is a growing trend, and expertise in particle reduction techniques for intermediates is evolving into a niche capability in its own right. It has taken on even more importance in recent years as the number of insoluble compounds with low bioavailability grows. And with dosages becoming smaller, tight control over particle size is even more critical.
According to PharmTech (Particle Size Reduction for Investigational New Drugs):
“More than 90% of small-molecule NCEs designed to be taken orally display solubility issues. Poor solubility makes absorption of the drug from the gastrointestinal tract into the bloodstream a challenge, and the resulting low bioavailability may require enabling technologies to achieve a therapeutic effect.
Most APIs in current development fall into DCS quadrant II (see chart, left), in that they have poor solubility but adequate permeability.”
Particle Size Distribution, or PSD, requirements are critical, since the smaller the particle size, the greater the efficacy (as there is a larger surface area – which translates to higher bioavailability). But if the particle size is too small, it could lead to toxicity. So the right balance has to be found.
The distribution of the particle sizes in a sample is a physical parameter, and is typically achieved using techniques such as controlled crystallization, post-drying micronization (e.g. jet milling) and wet milling.
How Many Requirement Tiers Are There?
Many projects involve products with a single tier of PSD requirements, for example, d90 < 10 microns (90% of the particles are 10 microns or less). As with any pharma project, challenges can arise even during single tier requirement products.
Projects become more challenging with two-tier requirements, in which materials are required to meet two distinct specifications. As the specifications move to three tiers, the difficulties become even more magnified. Controlling the particle sizes – for example, matching between the various tiers of d50/d90 – can require a combination of different particle reduction and particle sizing techniques.
Complex Particle Size Distribution Projects
In response to the growing need for tight control over particle size, Neuland launched a dedicated particle size engineering lab containing facilities for both dry and wet milling, and micronization. Some projects requiring a specific particle size and distribution have been completed which necessitated the use of all three size reduction methods. We’ve also adopted the latest particle size engineering technologies, including implementing inline and online particle size meters as well as the latest crystallization techniques.
We’ve conducted particle size engineering studies using micronization for products such as Indacaterol maleate (less than 5 microns) and Ticagrelor (less than 10 microns). In another project, data generated on experiments with the compound Levetiracetam were used to optimize process conditions to meet the PSD requirement prior to kg scale production.
The Four-Tier Specification – QbD & Labwork
Neuland recently worked on a project where the Particle Size Distributions (PSD) requirements were quite unique.
The product consisted of a 4-tier PSD specification. The API required a specific percentage mix of particle sizes to meet the customer’s formulation needs. The project also called for careful attention to the physical powder properties, to avoid negatively impacting processing & bulk powder handling.
When scaling a project from the bench to commercial bulk API quantities, knowledge of size reduction techniques and their impact on characteristics (e.g., flowability & hardness) is vital to successful process development.
This 4-tier project required a great deal of lab work. Using a QbD (Quality by Design) approach to process development, the team in Neuland’s Process Engineering (PE) Lab developed an efficient, effective and safe process to achieve the necessary complex specs.
QbD provides an effective framework under which processes can be modified to account for variations in the properties of the API. The project leveraged a number of QbD elements – process control, continuous improvement, Design of Experiments (DoE) and Design Space – to ensure a viable & scalable process emerged.
Neuland made key decisions during the process development project to achieve the customer’s unique specifications.
Instead of using a multi-milling technology, we chose a jet-stream milling technique. Jet mills grind materials using a jet of air or gas to impact particles into each other. Multimills operate differently, relying on beaters with different rotating edges to granulate and screen particles.
Neuland designed and created a special sieve to meet all four of the size specifications. (The actual process by which we arrived at the right sieve is confidential, but it was a critical aspect in driving development and commercialization forward.)
Particles in All Shapes & Sizes
From novel drug delivery techniques (e.g., inhalables) to the efficacy and safety of intermediates, particle size now plays a prominent role in pharma drug development & scale-up. The data generated by particle size distribution studies and experiments has expanded upstream – away from typical dosage form considerations – and is now used by the pharma industry earlier in the drug design process.
Are you ready to talk about your molecules? Contact us today.
Think about your last project.
How many individuals and departments participated? How many locations around the world did it involve? How smoothly did the project progress?
Could you have improved outcomes?
Pharma Projects Are Growing Increasingly Complex
In the pharmaceutical industry, projects now commonly span numerous stakeholders across multiple geographies. The challenges involved with complex project management can materialize at virtually any stage: scope management, project planning, stakeholder & team management, regulatory strategy development, or budgeting & timeline development.
Pharmaceutical API Project Management
In recent years – as constantly-changing business dynamics have combined with more complex project environments – a firm grasp of project management has become more important.
Project management in the pharmaceutical and biopharmaceutical industries is slightly unique when compared to other sectors, such as infrastructure or IT. Though the formal adoption and use of project management is a bit less mature compared to the IT sector, the challenges confronting pharma are more or less the same – and sometimes far more complex – than non-life science-related spaces.
Project management is the heart and soul of virtually every undertaking in our industry. It has become the driving force of any project to track, monitor and deliver projects within the expected timelines & budget specified. Given the risky nature of scientific research, project management is closely aligned with risk management.
Waterfall and Agile Project Management Approaches
In the lexicon of project management, there are two approaches to managing pharmaceutical research or manufacturing projects. One is the Waterfall approach, and the other is Agile management.
The Waterfall Development Approach
The Waterfall approach remains the pharma industry’s primary approach to product development. The name describes the methodology – phases flow downward, like a waterfall. As a methodology, it is quite appropriate to the drug industry since requirements are often static, and well-understood from the start.
In the Waterfall approach, projects consist of a series of steps or phases which must be performed sequentially. The next phase begins when the preceding phase is completed and verified. Common phases performed in order include:
The Agile Development Approach
Agile development takes a more flexible approach. Instead of delineating all of the requirements upfront (which may not be known), Agile defines each project as a set of tasks – many of which can be completed concurrently, rather than sequentially. Agile relies less on pre-planning, and more on flexibility and human interaction. Created in 2001, it was intended to streamline software development processes by de-emphasizing inefficient practices such as heavy documentation, excessive meetings, and rigid adherence to process.
In the June 2019 issue of PharmaVoice Denise Myshko discussed the rise of Agile management in the pharma space (The Agile R&D Organization), writing:
“Agile project management, first introduced in 2001, started out as a method used in software development that challenged the traditional, linear development model. The same benefits realized by the software industry, experts say, can be realized in pharmaceutical R&D.”
But – while it can help shorten drug development cycles – pharma does have some concerns with Agile. The de-emphasis on processes and tools seems to run counter to the highly-regulated nature of drug development – though it has also been pointed out that the reliance on human interactions instead “makes a robust process even stronger.”
The Right Pharma API Project Management Approach: What’s the Verdict?
Circumstances often dictate necessity. Different project management methodologies will appeal to different project types, timelines and other factors. Agile management in pharma – while lacking some of the robust documentation and other processes common to the industry – is growing in response to the need for more responsive approaches to address project uncertainties and the quest for shorter development cycles.
Neuland & the Balanced Matrix Approach
Hanover Research’s Best Practices for Matrix Organizational Structures (2013) describes balanced (or partial) matrix structures as:
“…considerably varied in form and might refer to a “temporary interdisciplinary task force for a specific purpose or a semi‐team structure developed in only part of the organization around certain functions or projects that need a high level of communication or coordination.”
At Neuland, we’ve adopted a balanced matrix design for project management, ensuring that technical leaders serve as the Project Managers (PMs). The balanced matrix gives Neuland the flexibility to create interdisciplinary, cross-functional teams, the need for which is dictated by the specifics of each project.
Although we follow the ‘Waterfall’ model (in which project planning, timelines and schedules are determined initially), we also utilize an ‘agile’ project methodology when appropriate. This allows us the flexibility to respond to issues as they arise during a project.
These two different approaches are not incongruous, and the end outcome remains the same regardless of approach: a safe and efficacious therapeutic. One method allows us to thoroughly plan out our static projects (ones with low likelihood of scope changes). The other method, well-suited to some of our earlier-stage projects, gives us (and the customer) the flexibility to adapt to changing or unpredictable circumstances, as well as tight deadlines.
Project Management Tools
To monitor and track the progress of our projects, Neuland uses the project management tool Concerto (which utilizes MS Project for the initial project planning). All project activities are sequenced or planned in parallel, depending on their dependencies. At the outset of every project, the following steps typically occur:
Our Project Management Office
Neuland’s Project Management Office (PMO) is made up of two groups: our project proposal team and our Project Coordinators (PCs).
Among their tasks, PCs manage project scope changes. The flexibility to manage project modifications is a necessity – especially in R&D and early phase projects. Projects shift over time and the earlier the project stage, the more likely it will see changes, additions or diversions over time.
You might be thinking since scope changes can and do happen, how are they typically handled at Neuland?
Below is our process for altering projects and communicating with customers:
Do you have an upcoming project? Contact us to find out how we can help ensure your project’s success.
An article at PharmTech by Felicity Thomas (Looking Beyond the Solubility Horizon) caught my eye recently as it discussed a pharma (and biopharma) industry trend that’s on the rise. Insoluble drug compounds now comprise nearly three-quarters of all new NCEs – potentially compromising bioavailability…and thus their value as therapeutics.
Fact is, very few of our customers are able to dismiss solubility concerns outright. While solubility challenges seem to exist on something of a spectrum – with some drug solubility issues much easier to resolve than others – nearly everyone sees concerns arise during development.
Why the upsurge? According to the article, it “is a trend that is anticipated to continue to grow as a result of the industry drive toward development of more molecularly complex chemical entities.”
Our team concurs: the overall complexity of molecules, along with their increasingly hydrophobic character, has led to increased obstacles that must be overcome during process development. It’s a challenge that continues through to formulation development and beyond.
‘Making the Insoluble Soluble’
The PharmTech article shares some of the physical techniques used to overcome insolubility – namely, particle size reduction – when chemical synthesis techniques or the use of specific excipients is not practical or effective.
Chemical modifications during the development & scaling of an API can seem straightforward (replacing or changing the concentration of an ingredient, or buffer & pH changes). Unfortunately, even the smallest changes can have significant repercussions in terms of pharmacodynamics and pharmacokinetics – rendering it often a less-than-ideal technique.
The preferred technique today for APIs is to physically modify the molecule – typically through milling (particle reduction). There are a number of different milling techniques, and each one has advantages and disadvantages. Much, of course, depending on the nature of the compound, its sensitivity to various forces (e.g., sheer or heat), and how successful a basic technique such as crystallization may be.
This topic was also discussed in a recent article at Drug Development & Delivery (Improving Bioavailability & Solubility: Chemical & Physical Modification vs. Formulation Development):
“Functional lipids are a versatile tool for formulators and offer delivery strategies like self-emulsifying drug delivery systems (SEDDS) and lipid nanoparticles (LNPs). Nanoemulsions (SEDDS, SMEDDS, SNEDDS) were developed to provide improved bioavailability, reproducibility, and enhanced API permeation.”
One conclusion of the article – “While physical and formulation strategies can individually increase bioavailability of molecules, a combinatorial approach may be the best” – perhaps best captures the increased complexity this issue poses to industry, and the need for increasingly complex – and multifaceted – solutions.
Neuland is no stranger to solubility challenges. Our NCE customers are seeing this issue emerge much more frequently than in decades past given the types of molecules we are developing. For this reason, we launched our PEL, or Process Engineering Lab (here’s a post on our PEL’s success stories with particle reduction). The PEL is well-suited to tackling particle engineering studies to resolve drug intermediate solubility issues.
And while we have had success via route selection or process modifications, we often find one of the various types of milling (e.g., jet milling or multi-milling) is a good option to optimize API solubility.
The advent of so many different techniques to address solubility, however, can make a combinatorial – and cross-functional (chemical, physical, formulation and/or delivery) – approach ideal. Dr. Bowers in the Drug Development & Delivery article sums it up best:
Does your company have questions about API development & solubility?
We’re here to help! Contact Us Today >
The pharma industry is facing some outsized business challenges at present – from burgeoning trade wars to downward-pricing pressures and increased regulatory scrutiny.
More than one conversation our team members have had recently has turned to cost controls, with an emphasis on supply chain security. The tit-for-tat tariff increases between the U.S. and China have left some C-level execs shaking their heads…and pondering the impacts given that only finished pharmaceuticals are exempt – and not chemicals or APIs.
In the U.S., drug pricing pressures are mounting, and the profusion of lower-priced generics exacerbates the situation. In the generic space itself, only one lucky winner gets the Paragraph IV benefit – even if only for 180 days. For everyone else, cost controls – whether in manufacturing, distribution, or some other part of the ingredient-to-customer chain – are the primary option for maintaining a competitive advantage.
The Attraction of Backward Integration in Pharma Supply Chains
These days, ‘stable and predictable’ and ‘pharma manufacturing’ are becoming almost diametrically-opposed concepts. Companies reliant on API manufacturers in China received a rude awakening in recent years, when multiple plants faced government action over environmental and safety violations. (And ongoing tariff uncertainty has done nothing to placate concerns.)
This has led companies who want to secure their supply chains to place much more emphasis on backward integration. There are several ways in which a pharma company could seek to backward integrate. In the classical sense of the term, they could acquire their suppliers, which – while vastly more expensive and not feasible for most companies – does constitute true backward integration.
More typically, however, pharma firms secure supply chains by backward integrating ingredient supply. Rather than purchase a facility outright, both small pharma and large MNCs are looking for suppliers who can alleviate their concerns – without creating other, unpredictable complications such as ‘supplier-turns-direct competitor.’ (See #3 in our list of key supplier traits for securing the API supply chain, below.)
One key benefit of backward integration is that it helps bring down costs by increasing bargaining power when negotiating prices.
But how can companies address these various supply chain impediments? What should they be looking for in their drug ingredient supply chain?
Securing the Pharma API Supply Chain: 4 Key Supplier Traits
There are three key elements to securing an API supply chain, each of which leads to further strengthening of the supply.
In the contract pharma business, this typically means the process for the raw material will be developed by supplier and then validated in-house. This reduces risk by ensuring greater control over the process, and eliminates the need for multiple raw ingredient sources – a practice which can lead to product variance/consistency and quality issues.
Greater control means greater predictability. With manufacturing performed in-house at Neuland, for example, we exert greater process control to ensure production, compliance and quality targets are all consistent & predictable.
At Neuland, we’re in a better position to backward integrate due to our acquisition of Unit III. This acquisition has ensured we have the commercial capacities needed to shift the manufacture of intermediates as needed.
Each of these four elements – in-house synthesis, multiple site security, a focus strictly on API supply and a supplier’s compliance track record & expertise – contributes to stronger API supply chains. As a whole, they provide a single- or multi-source backward integration API supply solution for pharma companies.
Does your business want to improve supply chains and drive profitability with stable, secure access to the highest-quality APIs? Learn more about Neuland’s supply chain-securing Pharma API Capabilities >
Peptide process development projects have increased in the last few years. Judging by our blog readership and social interactions, interest in peptide drugs is continuing to grow by leaps and bounds.
We’ve seen questions focused on whether a given peptide can even be produced give way to questions focused on whether a peptide can be produced at X volume, for Y cost and at Z purity.
Peptides are a unique class of drugs nestled between small molecules and proteins. Between 1920 (the introduction of the world’s first peptide drug – insulin) and 2017, more than 60 peptides have been approved by the FDA.
Peptides are attractive as a drug class due to their high specificity and low toxicity, but certain properties have historically limited its utility (e.g., parenteral route of administration, proteolytic instability, etc.). These are among the limitations of peptides that are currently being overcome, and have been the focus on increased research and industry attention over the last decade or so.
We’ve written on a number of peptide topics over the years, and much of our focus has been on the various techniques used to synthesize the peptide API – liquid phase, solid or hybrid.
History of Peptide Synthesis
Peptide synthesis technique selection is extremely important. The very first liquid phase synthesis of a peptide hormone, Oxytocin, was reported in 1954 – an elegant synthesis for which Vincent du Vigneaud received the Nobel Prize.
In 1963, Robert Bruce Merrifield reported synthesis of a tetrapeptide (4 amino acids) using solid phase synthesis. While solid phase synthesis is convenient to perform, liquid phase synthesis is preferred for peptides which:
Most of our peptide projects extend well beyond synthesis technique selection and development to encompass other key areas of peptide drug commercialization.
Scale-up, confirmatory batch production, process optimization and analytical methods development are all milestones on the path a peptide therapeutic takes through clinical trials to market. It is the collective advances in these related disciplines – better chromatographic resolutions, or our greater knowledgebase for methods creation and validation, for example – which have contributed to the resurgence of pharma peptides.
16 Amino Acids. 100 Kilograms. 98% Purity!
Our previous liquid phase synthesis of a decapeptide (10 amino acids) at 35 Kg scale involved 24 steps. At the time, we considered this a very significant peptide manufacturing milestone for Neuland.
Then one of our U.S.-based customers asked us to develop a liquid phase synthesis route for a cyclic sixteen amino acid peptide API which possessed multiple disulfide bonds.
They also wanted the peptide scalable to 100+ kilograms per year.
For this particular API, Neuland developed a liquid phase synthesis strategy using four protected segments, including:
Overall, the final process involved 40 isolated stages. Each stage required evaluation of optimal reaction conditions. For each of the 40 steps, reaction parameters – including temperature, reactant molar ratios, and pH – were optimized.
Specific analytical methods were also developed, and critical process parameters and critical quality attributes were established for each stage.
To demonstrate scalability, Neuland prepared all the segments in several hundred grams quantities (with purity exceeding 95%).
Process consistency was established by conducting three lab verification batches for each of the stages. The yield for the verification batch of the lyophilized peptide API (post-preparative HPLC) was ~30% and the final API purity was 98+%, per the customer’s specification.
The Peptide Class is in Session
While this was just a single project at Neuland, it was an example of a successful – and quite complex – liquid phase synthesis scaled to commercial volumes.
From analytical and process instrumentation to novel peptide assembly methods, much has happened to pave the way for the peptide API industry to routinely discuss projects at 100+ kg/yr scales…at 98+% purities…across 40 manufacturing steps.
We’ve reached a juncture where complex peptide manufacturing techniques and instrumentation are starting to bend the cost- and scale curves, just as the science of peptides seems to be coming to fruition. This is building a more compelling revenue case for peptide therapeutics – something that has generally been out of reach.
The peptide class, it seems, is in session.
June is Alzheimer’s and Brain Awareness Month.
Alzheimer’s Disease (AD) is a heartbreaking and tragic condition affecting millions of families worldwide. This month, we highlight how health and pharma intersect.
Gender & Alzheimer’s Disease
Gender is a key risk factor for Alzheimer’s Disease…much more so for women than men.
From the Journal of Alzheimer’s Disease:
“The incidence of the disease is higher in women than in men, and this cannot simply be attributed to the higher longevity of women versus men. Thus, there must be a specific pathogenic mechanism to explain the higher incidence of AD cases in women. In this regard, it is notable that mitochondria from young females are protected against amyloid-beta toxicity, generate less reactive oxygen species, and release less apoptogenic signals than those from males. However, all this advantage is lost in mitochondria from old females.”
How much more likely are women than men to suffer from AD? Cognitive Vitality, a program of the Alzheimer’s Drug Discovery Foundation, reported last summer that “more than 5.5 million Americans are living with Alzheimer’s disease, of whom two-thirds are women.”
Treating Alzheimer’s Disease
Worldwide, 50 million people suffer from Alzheimer’s and other forms of dementia. While there are currently no drugs which can cure Alzheimer’s outright, common drug interventions for AD can – in some patients – temporarily alleviate the symptoms or slow their progression.
Such drugs include cholinesterase inhibitors such as the Donepezil, which is approved to treat all stages of Alzheimer’s. Other cholinesterase inhibitors (Rivastigmine and Galantamine) are approved to treat mild to moderate AD.
The Alzheimer’s Association discusses another drug, Memantine (Namenda) – as well as a combination of memantine and Donepezil (Namzaric) as treatments which are approved by the FDA for moderate to severe Alzheimer’s.
There are also a number of drugs in various stages of development worldwide, including selective beta secretase inhibitors, immunotherapies, inhibitors targeting the accumulation of tau, anti-inflammatory combinatorials and more.
Donepezil
Neuland is a manufacturer of Donepezil – the generic API of Aricept (we produce both Donepezil base and Donepezil hydrochloride). Donepzeil was first approved in 1996, and is a reversible acetylcholinesterase inhibitor. As an enzyme blocker, controlled studies have shown modest benefits in cognition or behavior. While it does not cure Alzheimer’s disease, it may temporarily improve memory, awareness, and the ability to function.
Ending Alzheimer’s – #ENDALZ
While drugs such as Donepezil can provide modest temporary benefit, the focus this month is on ending Alzheimer’s entirely. Essential to this are ongoing efforts to build awareness – awareness of Alzheimer’s disease itself, its progression & stages and its signs & symptoms.
Preventing Alzheimer’s Disease: What You Need to Know
While scientists continue to look for a cure to Alzheimer’s, or at least a way to stop it’s progression more permanently, there are steps we can take to ensure our brains remain as healthy as possible. Check out these tips from Harvard Health on keeping your brain healthy.
Want More Alzheimer’s Resources?
The NIH’s National Institute on Aging is a good resource for general information on Alzheimer’s Disease, and CenterWatch has updated lists of dementia-related research and clinical trials. DDNews’ yearly neuroscience report is also worthwhile – here’s the April 2019 report.
Rise of the Peptide Era
Peptide synthesis has a long pharmaceutical history, stretching back to the early 1900s – and then followed by a lengthy period of dormancy. From sciencedirect.com:
“Starting about a century ago (World War I), the advent of the modern drug era came with pioneering therapeutic compounds like the opiate morphine and the cyclic peptide penicillin, followed in the early 1920s by the (poly)peptide insulin. These drugs introduced a new standard in disease treatment. Although peptides thus held their place among the initial therapeutic discoveries, small molecules rapidly took preference in the drug development industry.”
Only recently have peptides gotten another look – and the pharma industry is seeing significant potential. In its most recent market report, Grandview Research estimated the peptide therapeutics market will reach nearly $50 billion. Of particular interest is what is driving the growth:
“Technological advancements in peptide manufacturing processes are one of the major factors driving the market growth during the forecast period. Manufacturers and suppliers are focusing on the adoption of novel technologies to manufacture efficient drug molecules with low time and capital investment. Improvement in purification & automation process and less generation of waste is an additional factor attributing toward market growth.”
Decreasing Barriers to Peptide Therapeutics _________________________________________
For peptide drugs, the list of barriers to entry have always seemed formidable:
These challenges all conspired to render the peptide class promising – but ultimately unrealizable.
It’s a far cry from the early days of pharma, when peptide-based compounds like penicillin, cyclosporine, and insulin first rose to prominence. Fast forward several decades – what exactly has changed to make peptides suddenly attractive as a therapeutic class?
The changes have come about due to a collection of advances in chemistry, biology, genomics, dosage formulation, combined with rapid shifts in our understanding of human health and exponential improvements in technology (from computational power & informatics to spectrometry, imaging and more).
Over the last two decades, we’ve seen sufficient advances in these different but interrelated areas begin to converge, enabling not a rethinking of peptides but rather the realization of their known benefits & potential.
These developments fall into three (very) broad categories:
Mucosal: use of nasal sprays and sublingual use
Oral: coatings are used to protect the active substance from digestion in the stomach, or to protect the peptide against peptidases
Transdermal: patches have been successfully developed
Finding the Right Peptide Synthesis Technique__________________________________________
Peptides are a complex drug class, and have historically proven challenging from a manufacturing standpoint. They are, however, experiencing a renaissance due to improvements in peptide synthesis, the development of high-throughput approaches and various innovations to overcome some of their traditional limitations, such as stability and half-life. These advances are expected to drive the peptide drug market to over $48 billion by 2025.
Most peptides between five and sixty amino acids are produced by standard solid phase peptide synthesis (SPPS) procedures. Multiple kilos of shorter length (up to 10 amino acids) are produced by solution phase methods. For longer peptides, containing up to 120 amino acids, segment condensation and ligation techniques are employed.
Choosing the Right Synthesis Technique for Your Peptide API
The decision regarding which production technique to use is driven by three pivotal factors:
Peptides are produced using one of three synthesis methods: liquid phase, solid phase or a hybrid approach. Each has its advantages and disadvantages.
Overcoming Peptide Chain Aggregation
The aggregation of peptide chains caused by intramolecular hydrogen bonds is a common challenge with longer or more complex peptides. It can result in slower and incomplete coupling reactions and incomplete deprotection of the Na-amino protecting group – meaning a modified or damaged peptide.
There are a number of steps taken to prevent aggregation during peptide synthesis, including cleavage and deprotection. The most commonly used – and mildest – method is Fmoc – the removal of the Fmoc group to expose the α-amino group. In addition to cleaving under very mild conditions, it is (typically, though not always) stable under acidic conditions as well.
Fmoc & Orthogonal Approaches to Peptide Synthesis
One of Fmoc’s greatest advantages is its ability to work well with other protecting groups (e.g., Boc) – allowing for an orthogonal approach – a common strategy in organic peptide synthesis.
Common Fmoc Methods for Disrupting Peptide Aggregation
Advances in peptide synthesis methods and ready availability of reagents that disrupt intramolecular hydrogen bonds have made complex syntheses much more practical. There are three Fmoc strategies for disrupting aggregation. The decision to use each one is directly dependent on the type of building block being used.
Rising to the Challenge: Emerging Peptide Tech ____________
Peptide purification techniques that can increase the resolution between related substances and the API are critical for establishing identity, purity & assay – and for increasing the preparative output. The ultimate goal: high-quality, affordable peptide APIs.
Evaporation – the most commonly used crystallization method for small peptides – is scalable, but isn’t an effective technique for producing or analyzing complex peptides. Emerging technologies, however, are playing in a key role in overcoming these hurdles. Hghlighted below are two such innovations driving improvements in purity and yield.
Molecular HivingTM
Developed by Neuland Labs’ collaboration partner Jitsubo Co. (Yokohama, Japan), Molecular Hiving is a manufacturing scale technique which offers tremendous cost advantages over traditional methods, whether LPPS or SPPS (Solid Phase Peptide Synthesis).
The technique uses TAG, hydrophobic benzyl alcohol or benzyl amine derivatives at C-terminus – instead of resins in solid phase synthesis (SPPS). The reactions of coupling to form peptides and deprotection of N-Fmoc or Boc in slightly hydrophilic solvent are performed in homogeneous solution (typical of LPPS).
Precipitation and isolation of a desired tagged-peptide is easily performed by adding a hydrophilic solvent to the reaction mixture.
By using its patent-protected achiral hydrophobic tags, peptide solubility can be controlled. A synthesis begins with the attachment of a patented hydrophobic tag to the C-terminal amino acid.
Peptide chemistry reactions are then performed in a hydrophobic solvent. When the reaction is complete, the tagged peptides can be precipitated and filtered.
The process effectively removes excess reagents present in the reaction mixture, providing high yields of high purity peptides.
RP-HPLC
In science labs, reversed phase high performance liquid chromatography (RP-HPLC) is used to analyze, characterize, separate, purify, and isolate small organic molecules, natural products, and biologically active molecules such as polypeptides, proteins and nucleotides.
In pharma, analytical RP-HPLC is employed specifically to release and characterize raw materials, intermediates and active pharmaceutical ingredients (APIs). Likewise, preparative RP-HPLC is used to commercially produce peptide APIs, along with most other complex APIs that cannot be crystallized.
The new method developed by Neuland uses C-18/C-8 derivatized silica, coated with a hydrophobic quaternary ammonium salt or quaternary phosphonium salt. It increases 7- to 12-fold the sample loading of the crude mixture of organic compounds including synthetic crude peptides. What causes such dramatic results is the additional surrogate stationary phase characteristic of the C-18/C-8 bound quaternary salt.
Secure Your Peptide API Supply Chain.
Supply chains have become mission-critical for the pharma industry, and peptide API manufacturing is no exception. Helping clients improve the security of their supply chains means maintaining the security of our own capabilities. At Neuland, we leverage ‘insulating facilities,’ a redundancy which provides customers with seamless, rapid supply transition in the event of a disruption. Contact us today to learn more about our capabilities, tools and techniques for peptide drug development & commercialization.
We’ve reached the two year anniversary of the first FDA approval of a deuterated molecule (April 2017, Teva’s Astedo – a deuterated version of tetrabenazine for the treatment of Huntington’s disease). It’s interesting to have witnessed the emergence of this unique space.
Deuteration of drugs came to prominence in the 1970s, but it took 40+ years for the first such drug to reach the market.
Teva’s Astedo (Deutetrabenazine) is similar to other deuterated products in that it possesses a longer half-life compared to non-deuterated versions of the same (often already-approved) drug. Generally, deuteration alters the metabolic, toxicological and pharmacokinetic properties of a drug – though it has been reported that most drugs would not derive any benefit from deuteration.
What is a Deuterated Drug?
From an earlier post we wrote on deuterated molecules: A deuterated drug is made by replacing a drug molecule’s carbon-hydrogen bond with a carbon-deuterium bond. As deuterium and hydrogen have nearly the same physical properties, deuterium substitution is the smallest structural change that can be made to a molecule.
Why Deuteration Matters
There are a number of well-known benefits to deuteration, including:
Lower Dosing
Deuterated drugs break down at slower rates than non-deuterated versions, resulting in a longer duration in the body. This translates into lower or less frequent doses.Reduced Toxicity
Fewer doses resulting from the longer half-life, in turn, can reduce the toxicity of the drug in the body. A 2019 article in Annals of Pharmacotherapy found that deuteration “may also redirect metabolic pathways in directions that reduce toxicities.”Increased Stability
Fewer drug interactions can occur due to the stability of deuterated compounds in the presence of other drugs.
Deuterated versions of existing drugs can benefit from improved pharmacokinetic or toxicological properties. Because of the kinetic isotope effect (which is the change in rate of a chemical reaction when one of the atoms in the reactants is substituted with one of the isotopes), drugs that contain deuterium may have significantly lower metabolism rates. As the C-D bond is ten times stronger than the C-H bond, it is much more resistant to chemical or enzymatic cleavage and the difficulty of breaking the bond can decrease the rate of metabolism.
Lower metabolism rates give deuterated drugs a longer half-life, lengthening the timeline for elimination from the body. This reduced metabolism can extend a drug’s desired effects, diminish its undesirable effects, and allow less frequent dosing. The replacement may also lower toxicity by reducing toxic metabolite formation.
A major potential advantage of deuterated compounds is the possibility of faster, more efficient, less costly clinical trials, because of the extensive testing the non-deuterated versions have previously undergone. The main reasons compounds fail during clinical trials are lack of efficacy, poor pharmacokinetics or toxicity. With deuterated drugs, efficacy is not in question – allowing the research to focus on pharmacokinetics and toxicity
Deuterated versions of drugs might also be able to obtain FDA approval via a 505(b)(2) NDA filing, a faster, less expensive route. (Read more: API Manufacturing of Deuterated Molecules.)
Patent Uncertainty – but Regulatory Certainty
The last decade has witnessed the rise of patents claiming deuterated versions of non-deuterated drugs. The intellectual property aspects of deuteration, however, remain a question mark.
Patent law has been the most problematic venue for deuterated molecules, primarily with concerns over the ‘obviousness’ of the invention. While there has yet to be any resolution to this uncertainty, it hasn’t stopped pharma companies – including Big Pharma – from adding deuterated versions of a prospective compound to their patent claims.
“The total value of transactions involving deuterated drugs is close to $5 billion. While the importance of §103 ‘obviousness’ rejections remains in patent applications under current prosecution, IPR of issued patents is developing and will affect likely affect §103 interpretations in this area. However, patents are still issuing with later priority dates, and further litigation will likely occur.”
Drugdiscoverytoday.com touched on the use of deuterated molecule patents as a defensive action in a 2017 article (Drug Developers Look to Deuterated Drugs as Risk Managed Opportunity):
“Patents are expected to play a major role in this segment, largely because the majority of deuterated drugs under development are approved APIs in undeuterated form. This dynamic has given rise to a significant level of defensive IP activity, in which companies patent deuterated APIs largely on speculation that the drug will prove to be efficacious and safe at some point in the future.”
On another front, deuteration in the pharma industry has received some much-needed clarity. With the regulatory status of deuterated compounds presumably settled by the FDA (FDA Determines that Deuterated Compounds are NCEs and Different Orphan Drugs Versus Non-deuterated Versions), there has been a further upswing in interest in the space.
Deuterated Drugs: Progress & Promise
The opportunities may stretch well beyond those listed in the chart below. A January 2019 article in the Journal of Medicinal Chemistry stated that deuteration:
“might provide an opportunity when facing problems in terms of metabolism-mediated toxicity, drug interactions, and low bioactivation. The use of deuterium is even broader, offering the opportunity to lower the degree of epimerization, reduce the dose of co-administered boosters, and discover compounds where deuterium is the basis for the mechanism of action.”
So what is happening right now in the field with deuterated candidates? Here’s a chart with indications and clinical status, of products ranging from Phase 1 all the way up to Phase 3.
Contact Neuland Labs today to discuss your deuterated compound needs.
The first in the class of drugs known as selective relaxant binding agents (SRBA), Sugammadex sodium is used to reverse anesthesia. Via 1:1 binding of rocuronium or vecuronium, it rapidly reverses any depth of neuromuscular block while avoiding cholinergic adverse effects. The generic ingredient in Merck’s Bridion®, Sugammadex reverses the effects of neuromuscular-blocking drugs that freeze vocal cords and muscles during surgery – allowing patients to be taken off breathing machines and go back to breathing on their own sooner.
Process Challenges Overcome by Neuland
Neuland has developed a robust, scalable, operationally safe process which consistently produces product as per desired yield and quality at higher volumes. The synthetic process consists of 3 steps:
In tech Sugammadex-Na (Stage 2), impurities at RRT 0.89 and 0.96 are very difficult to remove and attributed to Stage 1 intermediate quality. This was accomplished with purification by crystallization and achieves 85% purity as per Stage 2 specifications.
The preparative HPLC method is sensitive to many variables, including input material solubility, pH, and column performance—all of which were largely overcome with appropriate checkpoints in the process.
A process was also established to improve yield for the failed fractions unable to load into the preparative HPLC column directly.
Neuland is the first generic player to have a granted process patent for the preparation of Sugammadex Sodium in India (IN 290882/Expiry: Aug 25, 2030), USA (US 9120876/Expiry: Jan 15, 2032) and Europe (EP 2609120B1/Expiry: Aug 23, 2031).
Neuland’s API quality meets the regulatory requirements regarding any SMUI to NMT 0.089%, based on dosage value.
Early launch opportunity:
To discuss opportunities and find out more about launching a product with Neuland’s Sugammadex, contact Neuland Labs today.
How the Valsartan Contamination Happened: Its Context & Implications
Posted on July 8, 2019 by Saharsh Davuluri
Last year’s valsartan contamination and recall brought some surprising chemical synthesis issues to light in the pharma industry. While the reactions used in generic valsartan production are known to be a source of certain impurities, they were below current disregard limits and didn’t raise any red flags. It was the impurities that no one thought to look for, however, which led to the recall.
Valsartan is an angiotensin receptor blocker, or ARB, used to treat high blood pressure & heart failure. Neuland Labs does not manufacture valsartan, but the chemical synthesis risk management takeaways from this series of events apply uniformly across the API industry.
Judging from the patents filed around that time, Novartis/Ciba-Geigys original method for the tetrazole-forming step relied on the use of tributyltin azide. The yield of this step was 65%.
Generic Valsartan – Better Yields, But Hidden Toxicity?
With valsartan, higher synthesis yields were critical in order to achieve costs low enough to capture the business of pharma companies.
Various methods for forming 5-substituted tetrazole cycles on nitrile groups with sodium azide had been around for some time – relying on the use of metal catalysts, strong Lewis acids or tertiary amines.
In September 2010 Zhejiang Huahai patented a sodium azide-based synthesis method for valsartan, resulting in much improved yields approaching 90%. At the time the inventors boasted: “The method has the advantages that the operation is simple, the yield is high, the product purity is high, and the industrial production is easy.”
But sodium azide, it turned out, was a dangerous substance whose toxicity compares to that of potassium cyanide. It was fatal if swallowed, inhaled or put in contact with the skin. Since the new synthesis method required bringing a stoichiometric excess of sodium azide to the reaction, an unreacted residue of this highly toxic substance would remain in the product.
To deal with the toxicity of sodium azide, Zhejiang Huahai’s valsartan process chemists opted to add nitrous acid to the production broth as soon as an in-process control confirmed the complete formation of the tetrazole cycle. They did so in the form of sodium nitrite – which in the acidic environment of the broth turned into nitrous acid. Nitrous acid was a known decontaminating agent of sodium azide. It caused the degradation of sodium azide to nitrogen gas, nitric oxide and sodium hydroxide. The toxicity issue was thus resolved.
NDMA: Toxicity Tragedy
Zhejiang Huahai patented this production method in 2014, but their valsartan process had been based on the use of sodium azide as far back as 2012. Tragically, Zhejiang Huahai’s chemists failed to realize that while eliminating the toxicity due to sodium azide, their process generated another toxic substance: N-nitrosodimethylamine (NDMA) – a probable carcinogen in humans.
The solvent of the tetrazole-forming step was dimethylformamide, whose industrial production process starts from dimethylamine. It is now suspected that the residue of dimethylamine in the solvent reacted with nitrous acid to generate NDMA.
The presence of this contaminant remained undetected until early June 2018, when the manufacturer was reviewing and optimizing its processes. It is important to underline that the levels of NDMA eventually identified in valsartan were well below 0.05% – the disregard limit of the European and American pharmacopoeias for the related substances of valsartan.
According to the European Medicines Agency (EMA), NDMA was found in Zhejiang Huahai’s valsartan, on average at 66.5 ppm, and at most at 120 ppm – enough to represent an unacceptable health hazard, but not enough to be distinguished from analytical noise during routine quality control of valsartan.
Besides, whereas HPLC was used for control of the related substances of valsartan, gas chromatography would be the preferred method for separating NDMA. In 2017 FDA investigators had reported occasional issues with the tests of impurities during inspections of Zhejiang Huahai, but those issues were not critical and concerned chromatography peaks above the disregard limit.
Since it was below the normal reporting level of impurities, the presence of NDMA had been missed for years, not due to any fault of the company’s quality control. Rather, it was missed as a consequence of the faulty assessment of the safety of the synthesis process.
The presence of the NDMA contamination implied that the company’s European pharmacopoeia (CEP) certificate of suitability for valsartan was wrong. The European Directorate for the Quality of Medicines (EDQM) thus suspended the validity of the certificate as soon as the contamination became known.
The EDQM assessors of valsartan’s CEP application dossier had failed to realize the risk, as had Zhejiang Huahai, the U.S. FDA and everyone else.
Sodium Nitrate – a Missed Red Flag
The risk of formation of carcinogenic nitrosamines from nitrites and secondary amines in acidic conditions has long been known to the food industry. It was not rocket science – yet it came as a surprise to the pharmaceutical industry.
The use of sodium nitrite in the valsartan processes of Zhejiang Huahai and other manufacturers should have been a red flag prompting an evaluation of any presence of secondary amines, but it did not. From this perspective, it would be a mistake to see Zhejiang Huahai as an exceptionally careless actor.
In fact, quite the contrary seems to be the case.
Better Synthesis Risk Management
This company actually managed the risk of genotoxic and mutagenic impurities better than the average manufacturer. For instance, in one of their products – dabigatran etexilate mesylate – Zhejiang Huahai had specified a tight ppm acceptance limit for control of the potential presence of ethyl mesylate.
Ethyl mesylate is a genotoxic substance known for having caused a carcinogenic contamination in Nelfinavir at a Swiss plant in 2007. Such careful controls are not commonly seen at mesylate substance manufacturing plants.
Zhejiang Huahai’s discovery of the presence of NDMA in valsartan in June 2018 was – of course – overdue, but anyone familiar with the API industry will recognize that it was beyond what the average generic API company would likely do.
How often do we see an elective ICH M7 compliance program at any API plant? Rather than any exceptional sin on the part of the manufacturer, the valsartan contamination event might reveal that the pharmaceutical industry – focused as it is on the quality of pharmaceutical ingredients – has not been paying enough attention to the safety of chemical synthesis processes.
As soon as the valsartan contamination became known, the manufacturer and regulatory authorities rushed to test NDMA in other company products. They were satisfied to detect no NDMA in those products.
Irbesartan, which is another tetrazole molecule, was one of those products. Like valsartan, Zhejiang Huahai synthesized it according to the sodium azide method. Unlike valsartan, though, no dimethylformamide was used, but triethylamine was – which implied the natural presence of a residue of diethylamine from the manufacturing process of triethylamine by alkylation of ammonia with ethanol.
Looking for the Right Impurities
Because sodium nitrite was used in this process, the potential contaminant that needed to be tested in irbesartan was not N-nitrosodimethylamine (NDMA), but Nnitrosodiethylamine (NDEA). Everyone was looking for the wrong impurity. Just like the valsartan process, the chemical synthesis process of irbesartan had not been carefully studied. The scope of investigation was extended to other valsartan manufacturers, as well.
On 16 July 2018, the European Medicines Agency wrote to a number of manufacturers of the substance to inquire about their production methods for a re-evaluation of risk of generation of NDMA. Obviously, the investigation will also need to be extended to candesartan cilexetil, irbesartan, losartan and olmesartanmedoxomil, as these substances contain 5-substituted tetrazole cycles that are formed through the same method based on sodium azide.
It seems we will have to look deeper and wider than just NDMA in valsartan.
A Proper Response to Drug Contamination
We can be confident the valsartan contamination incident will be corrected although some patients will suffer serious consequences. Zhejiang Huahai reacted to their discovery responsibly. They halted production, sealed the stocks at the warehouse, and promptly notified the authorities and customers. The synthesis process will undoubtedly be modified, and NDMA will be routinely evaluated in valsartan.
This event will eventually be brought under control. But we would do well to understand that the contamination of valsartan remained undetected for years because the industry’s approach to the quality control of pharmaceutical ingredients tends to focus on the generally-harmless related substances of synthesis.
The Future of API Quality Management
The troubling question is: How many NDMA, NDEA, ethyl mesilate and other highly toxic, low concentration, impurities might lie hidden in the hundreds of pharmaceutical ingredients made by thousands of manufacturers around the world?
Something needs to change in our quality management of pharmaceutical ingredients, not only to prevent similar contaminants in the future, but also to become aware of the ones which may be there – right now – in our medicines.
This article was first published in Neuland’s internal newsletter, Neuworld, by Ashok Gawate – Neuland’s General Manager of Developmental Quality Assurance & Regulatory Affairs.