Cynthia A. Challener is a contributing editor to Pharmaceutical Technology.

Cynthia A. Challener

Medicinal chemistry generally involves the preparation of a lead drug candidate on a milligram scale and uses non-optimized chemistry that will produce the target in the shortest time possible. Often hundreds to thousands of compounds must be synthesized for testing against the target. The chemistry to the specific target is therefore typically not optimized but is phase-appropriate for this stage of development. The process chemistry group then develops safe, robust, and efficient chemistry to enable the preparation of multi-kilogram quantities of the API. This approach is the case for complex heterocyclic APIs. Recent efforts at Genentech and Pfizer and by Phil S. Baran at The Scripps Research Institute have led to improved, practical methods for the synthesis of such complex heterocyclic compounds.


  In one case study from Genentech, the PI3k β-sparing inhibitor Taselisib (GDC-0032) was discovered as a potential treatment for breast cancer (1). The main structural feature of Taselisib is a seven-membered benzoxazepine core that is substituted with a functionalized pyrazole at one end and an 

-isopropyl-3-methyl-1,2,4-triazole heterocycle at the other end.

The discovery route to prepare the benzoxazepine core of Taselisib required eight chemical steps from commercially available 3-bromophenol, according to Travis Remarchuk, a scientist in the small molecule process chemistry group at Genentech. He notes that while this chemistry was successful for producing the first five kilograms of the benzoxazepine core, it involved the use of hazardous reagents including carbon monoxide gas, 

-dimethylacetamide dimethyl acetal, and 1,2-dibromoethane and, therefore, was not amenable to the large-scale production of hundreds of kilograms. As a result, it was necessary to consider alternative and more practical routes for the preparation of the benzoxazepine core.

In the second-generation process route, Remarchuk explains that a pre-assembled 

-isopropyl-3-methyl-1,2,4-triazole was prepared via a one-pot, two-step synthesis from isopropylhydrazine. This triazole was then converted to a chloroketone derivative, which was directly reacted in a convergent manner with an aryl amidine to generate the fluoroaryl imidazole ring system. The seven-membered benzoxazepine core compound was then installed via alkylation with ethylene carbonate. “Notably, this reagent is a much safer alternative to 1,2-dibromoethane,” says Remarchuk. Following alkylation of the imidazole, the hydroxyl group underwent S

2 substitution with the aryl fluoride of a second equivalent of the imidazole in the same reaction pot to afford the carboxylic acid precursor to the API. “Using this approach, which involved more efficient methods for assembling both the imidazole ring system and the 1,2,4-triazole component, more than 60 kg of the product was manufactured for the Phase I resupply of the API,” Remarchuk observes.

A third-generation route was then developed that involved an efficient three-step, one-pot synthesis of the carboxylic acid precursor. In addition, in the final step of the API synthesis, the carboxylic acid group was converted to the primary amide using 1,1-carbonyldiimidazole (CDI) in place of the guanidinium coupling reagent HATU, which is not attractive for use in the last step of the synthesis due to release of several byproducts (tetramethylurea, hydroxybenzotriazole, and hexafluorophosphate anion) that require rigorous analytical testing to mitigate any safety risk for the patients, according to Remarchuk. The CDI coupling reagent is used in several other Genentech small molecule APIs in development.

Pyrazinyl-imidazo and pyrazinyl-pyrazolo pyridines from Pfizer


Pfizer was interested in compounds containing 5/6 fused ring systems as candidates for oncology treatments. One of the lead compounds, a 3-pyrazinyl-imidazo[1,2-a]pyridine was initially prepared via a palladium-catalyzed reaction of 2,6-dichloropyrazine involving direct arylation at the 3 position of the imidazo ring. This reaction was not amenable to the synthesis of a library of compounds. In addition, few imidazo pyridines are commercially available, and they were synthesized using chloroacetaldehyde, which is a toxic reagent. Therefore, an alternative route to 3-pyrazinyl-imidazo[1,2-a]pyridines for both compound library synthesis and potentially larger-scale preparation was needed.

Based on the known reaction of a dithiane with 2,6-dichloropyrazine involving nucleophilic tele-substitution, Michael R. Collins, a senior principal scientist at Pfizer, attempted the reaction of 2,3-dichloropyrazines with methyl vinyl ether (metallated), which proceeded as desired to afford the 2,6-disubstituted pyrazine products in good yields (50-60%) (2). A range of 3-pyrazinyl-imidazo[1,2-a]pyridines were then obtained in 31-76% yield by reacting the enol ether intermediates with N-bromosuccinimide in dioxane/water to generate the corresponding hemiacetals, followed by the addition of a 2-amino pyridine without isolation (2). In this reaction, the ring nitrogen of the pyridine displaces the bromide of the bromohydrin. “This reaction is very advantageous because it is done in one pot,” says Collins. The overall yields for both steps were also higher than those obtained for the palladium-catalyzed direct arylation route. “Not only does the reaction proceed fairly rapidly in decent yields, it is possible to prepare a wide variety of imadazo heterocycles, which is important for library synthesis,” Collins observes. He adds that substituents in the 6-position of 2-amino pyridine do not hinder the reaction with the enol ether.  The analogous compound was formed only in trace quantities using the Pd catalyzed procedure.

Separately, Collins and his colleagues developed an efficient route to 3-pyrazinyl-pyrazolo[1,5-a]pyridines via the [3+2] cycloaddition of enol ethers and 4-substituted 1-aminopyridinim iodides that is, according to Collins, simple to perform, scalable, and proceeds at room temperature. In addition, the reaction proceeds in good yield with 1-aminopyridinium iodides bearing both electron withdrawing and electron donating substituents at the 4-position (3). In this case, to identify the optimum reaction conditions (base and solvent), a high-throughput reaction screen was performed. According to Collins, the best results were obtained using potassium tert-pentylate, sodium hydride, or potassium hexamethyldisilazide in tert-amyl alcohol with a pyrazinyl enol ether.

Sulfur reagents for the alkylation of heterocycles from Scripps and Pfizer


The Baran group at The Scripps Research Institute, in conjunction with Collins and his colleagues at Pfizer, has also recently developed new reagents for the functionalization of heteroarene compounds. In one example, inexpensive, carboxylic acids are converted to sulfinate salts via an interrupted Barton decarboxylation reaction (4). The generated sulfinate salts are high value reagents and efficient radical precursors. The researchers readily prepared 10 different sulfinate reagents. One of the most interesting, according to Collins, is trifluoromethyl cyclopropyl sulfinate (TFCS-Na), which is effective for the C-H functionalization of various heterocycles. Most importantly, the reaction of the sulfinates is highly tolerant of a wide variety of functional groups, thus allowing for the introduction of substituents in the later stages of a synthesis, according to Collins.

In a second example, Baran and the Pfizer researchers developed a practical method for the methylation of heteroarenes via C-H functionalization using zinc bis(phenylsulfonyl-methanesulfinate), or PSMS (5). This reagent was designed based on S-adenosylmethionine (SAM), a biologically relevant methylating reagent. In the reaction with PSMS, a (phenylsulfonyl)methylated intermediate is generated that is readily separated from the reaction mixture, and subsequent desulfonylation reveals the methylated (or deuteriomethylated) product. As with the previous sulfinate-based C-H activation reaction, this transformation proceeds under mild conditions in air at room temperature and tolerates numerous functional groups, allowing for functionalization of pharmaceutical intermediates in the later stages of complex synthetic routes, according to Collins.


  1.	C.O. Ndubaku et al., J. Med. Chem., 56 (11) 4597-4610 (2013).
  2.	M.R. Collins et al., Tet. Lett., 51 (27) 3528-3530 (2010).
  3.	M.R. Collins et al., Tet. Lett., 53 (33), 4372-4375 (2012).
  4.	P.S. Baran et al., Ang. Chem. Int. Ed., 53 (37) 9851-9855 (2014).
  5.	P.S. Baran et al., J. Am. Chem. Soc., 136 (13) 4853-4856 (2014). 


Cynthia A. Challener is a contributing editor at 

Articles

New practical approaches to the synthesis of complex heterocycles are reviewed.

Advances in Large-Scale Heterocyclic Synthesis

Particulate matter in parenteral drugs has been recognized as a risk to patients for nearly two centuries. Contaminants can come from the environment, packaging materials, formulation ingredients, interactions between the formulation and the product packaging, or be generated during processing (1). Therefore, with an in-depth understanding of the raw material, product, packaging properties, and manufacturing processes, it should be possible to establish systems to reduce particulate matter contamination of parenteral formulations. An apparent increase in the number of recalls due to particulate contamination has drawn the attention of the industry and led to a greater focus on improving quality systems across the supply chain. One aspect of those efforts is the implementation of quality by design (QbD) to ensure consistent and robust quality.


In a 2013 article, Stephen E. Langille, a senior microbiology reviewer in the Office of Pharmaceutical Science at FDA’s Center for Drug Evaluation and Research (CDER), estimated that approximately 190 million liters of intravenous fluids are administered to patients each year in the United States (1). Several different clinical effects ranging from minor problems to serious complications and death have occurred as a result of the injection of particulate matter (1). Therefore, particulate matter contamination is a real concern for the pharmaceutical industry.

The consequences depend significantly on the size, shape, quantity, and composition of the particulate matter, as well as the method of administration and level of risk presented by the patient (1). Large, hard non-spherical particles can block blood flow and cause emboli, while large, softer, spherical particles may collect in organs and cause damage over time. Premature infants and patients suffering from severe tissue damage may be at greater risk from harm due to particulate matter contamination; similarly, vascular injection appears to present higher risk. In addition, critically ill patients tend to receive large quantities of parenteral therapies and, often, larger doses of particulate matter (1).


  Particulate contaminants are generally classified as extrinsic, intrinsic, or inherent, according to Tony Perry, director of regional quality for pharmaceutical packaging with SCHOTT North America. Extrinsic particulates originate from outside the process and include, for example, garment fibers and plastic particles. Intrinsic particulates are generated from within the glass vial such as glass flakes that delaminate from the vial wall. Inherent particulates are derived from the formulation itself, such as when a portion of it aggregates or crystallizes.
  
  There have been recent recalls attributed to all three types of particulates. In August 2014, Baxter voluntarily recalled in the US two lots of Dianeal Low Calcium Peritoneal Dialysis Solution due to the presence of oxidized stainless steel, garment fiber, and polyvinyl chloride particulate matter identified during the manufacturing process (2). Cephalon’s January 2012 voluntary recall of Treanda (bendamustine HCL) for Injection was based on the identification of glass fragments in a single vial (3). In December 2012, Hospira issued a voluntary recall in the US of three lots of carboplatin injection due to presence of visible particulates identified as Carboplatin crystals (4).

In fact, particulate contamination in parenteral drugs packaged in glass vials has created significant drug shortages recently, according to Perry. He notes that according to the FDA Office of Manufacturing and Product Quality, from 2008-2012 the presence of visible particles accounted for 22% of all drug recalls (5).
  


  Various industry players point to many different reasons for the increase in recalls due to particulates. “Today, quality has never been higher, but the manufacturing process is more versatile and complex than ever before,” states Wolfgang Weikmann, senior vice-president of quality for Vetter Pharma-Fertigung. “As a result, there are numerous individual process steps and a multitude of single components (e.g., the glass barrel, stoppers, caps) that serve as potential sources for particulate contamination during production,” says Weikmann. The growing use of prefilled syringes is another contributor to the increased incidence of problems with visible particulate matter, according to an industry expert. The expert adds that the continuing predominance of protein therapeutic agents has also resulted in more numerous mechanisms by which particulates can develop, because proteins are known to interact with components of the primary packaging system under certain conditions.

As demand from customers and regulatory authorities for ever-higher quality continues to grow, there is also a greater awareness of the possibility of particulate contamination, according to Weikmann. “There is definitely a heightened sensitivity in the industry to particulates given the greater understanding of their potential safety implications, and that led to a greater number of reports,” says Fran L. DeGrazio, vice-president of global R&D, strategic program management, and technical customer support for West Pharmaceutical Services. In particular, according to an industry expert, there is a growing awareness of the importance of subvisible particles with diameters in the range from 2-10 microns, which are currently below the “radar” of compendial testing.  “The number of particles in that range is enormous compared to the number of particles with diameters above 10 microns, and these colloidal particles can aggregate over time, producing visible particles,” the expert explains.

Industry understanding of the physical and chemical mechanisms of particulate formation is also improving. For instance, shear denaturation can produce visible particles, according to an industry expert. “There are instances where the type of filling pump (piston vs. peristaltic) makes an observable difference in the development of particulate matter in a drug product,” the expert says.

Investigations of glass delamination mechanisms are also providing insights that are leading to new glass manufacturing methods. Glass delamination is normally the result of chemical reactions between the drug and the interior surface of the glass container. “The occurrence of these reactions is the result of a complex interplay of different variables, such as the type of glass container, glass type (composition), pH range, drug type, and/or drug formulation (chemistry of the formulation). Importantly, a change in a single variable can make the difference between success and failure,” observes Dan Haines, scientific advisor, Pharma Services with SCHOTT North America. Additional risk factors have the potential to influence the possibility of delamination, including the storage time and temperature, the container manufacturing conditions, and the sterilization process.  
  
  


  The industry as a whole has tried to bring more visability to the particulates issue, according to DeGrazio. “Parenteral manufacturers have taken a number of actions to address the issue, including optimization of comprehensive quality management systems starting with supplier audits through to final visual inspections, as well as implementing permanent process monitoring approaches that are designed to detect potential hazards,” Weikmann says. 
  
  One biopharmaceutical company, for example, is focusing on understanding shear effects on particulate formation, particularly from filling pumps, through measurement of changes in conformation that could eventually lead to aggregation, and thus particulate formation, according to an industry expert. His company is also using instruments such as the FlowCAM (Fluid Imaging Technologies) and Micro–flow Imaging (ProteinSimple) to investigate subvisible particles.

Other activities at biopharmaceutical companies include making adjustments to fill and finish processes and the development of new material and system innovations, such as polymers and special biotech delivery systems, to reduce possible particulate contamination. Glass manufacturers are also responding by adjusting manufacturing processes and developing alternate methods that minimize the types of issues that have been seen in the marketplace, according to DeGrazio.

Importantly, there is greater sharing of knowledge between all of the involved parties. “Closer cooperation with suppliers, logistic partners, and technical engineering supports the implementation of corrective and preventive actions along the supply chain,” notes Weikmann. Collaborations with critical external partners, such as container producers that have shifted the focus to quality instead of treating glass vials as a commodity, are helping drug companies understand products and processes and improve overall quality, according to Perry. “By incorporating supplier expertise up front and engaging in information exchange from the beginning to the end of the drug development process, manufacturers can ensure that the material is used in the correct way,” he says.  Perry also notes that new guidance covering inspections is also providing manufacturers with further support to ensure quality.


Another approach that many companies are taking to improve quality, reduce the risk of particulate contamination, and avoid recalls involves the implementation of programs such as Six Sigma, risk management, right first time, and QbD, according to Perry. “The focus is now on minimizing the risk and doing it right the first time. These tools ensure that processes are well managed by understanding the key process parameters and risks associated with those parameters,” he explains.

“The very heart of the QbD concept is that quality is built into a product based on an in-depth understanding of the compound and the process by which it is developed and manufactured. Critical steps in the fill and finish process of parenteral manufacturing that affect quality are identified and their influence evaluated. Matching the appropriate processes to the actual needs of the product may help to identify potential risks in the process including possible sources for particulate contamination,” says Weikmann. For a CDMO like Vetter, he adds that the QbD approach is an important concept, primarily because of the many advantages it offers to industry stakeholders. “This approach enables consistent and robust production of high quality products and, therefore, the reduction of batch failures and stock-outs. It also offers the potential for greater confidence in drug quality and may reduce the need for intensive oversight by regulatory authorities,” Weikmann asserts.

For glass manufacturers, a QbD approach ensures a good understanding of which material and process inputs have an impact on glass particulates, as well as the ways in which the process and material interactions could lead to certain glass characteristics that predispose the glass to particulate formation, according to DeGrazio.

The implementation and success of QbD is also a way to help build long-lasting relationships with customers and key partners, according to Perry. “By taking a global view of our processes and products, we have been able to shift our focus from price-based discussions to total cost of ownership and quality. With QbD, we have adopted more of a risk-based approach to production and in the end have been able to look further down the value chain to make sure we are doing what is right for patients,” he comments.


These numerous benefits of QbD aren’t realized without significant effort, however. QbD is essentially a holistic, proactive, science-and-risk-based approach to the development and manufacturing of drugs, and proper implementation presents a variety of challenges for the manufacturer. According to an industry expert, the biggest issue is the lack of a clear translation from the broad principles of QbD to specific implementation actions. “It is definitely necessary to have the right level of technical ability within the organization to understand and implement QbD effectively,” Perry states. In addition, the organizational mindset must be aligned and willing to take on such programs and to live by the relevant principles and disciplines. “QbD cannot be seen as the next fad and is most successful when driven from the top of the organization,” adds Perry.

Time and cost are also issues. “Incorporating QbD into a process takes more time, and due to the need for improved understanding and greater testing, costs more money,” DeGrazio says. She goes on to say, however, that in the long run, use of a QbD approach should reduce many of the downstream issues that can occur, and for those that do occur, allow for better knowledge as to why. As a result, QbD should ultimately help the industry reduce costs.

Additional challenges can also include finding the right business partners that share the same quality understanding and meeting increasing regulatory requirements, such as the FDA’s process validation guidance, according to Weikmann.

Baxter, “Baxter Voluntarily Initiates U.S. Recall of Two Lots of Peritoneal Dialysis Solution Due to Presence of Particulate Matter,” Press Release, Aug. 13, 2014.

Cephalon, “Cephalon, Inc. issues a voluntary nationwide recall of Treanda (bendamustine HCL) for Injection 25mg/Vial Due to Particulate Matter,” Press Release, Jan. 27, 2012. 

Hospira Issues Voluntary Nationwide Recall of Three Lots of Carboplatin Injection Due to Visible Particulate Matter

,” Press Release, Dec.14, 2012,  accessed Oct. 7, 2014.

John G. Shabushnig, Insight Pharma Consulting, LLC, “

Detection and Control of Visible Particles in Injectable Products

The parenteral manufacturing industry is taking action to address particulate contamination issues.

Parenterals, Particulates, and Quality by Design

Using a design-of-experiment (DoE) approach allows a formulation development scientist to examine the formulation design space in a statistically significant manner from the beginning of experimentation. In addition, a DoE-driven approach meets the International Conference on Harmonization Q8 guidelines for multivariate design space and the subsequent justification of formulation components when developing a drug product, according to Steven R. LaBrenz, scientific director, pharmaceutical development and manufacturing sciences with Janssen Research & Development. At the same time, DoE results depend on the selected critical parameters and the sample material used in the studies. In addition, a large amount of data is generated. Consequently, reaping the benefits requires a significant commitment to DoE, including the training of researchers in study design and data-processing techniques.


One of the major advantages of the DoE approach is the ability to study the effects of multiple excipients and their interactions in a formulation at the same time, unlike in the traditional one-factor-at-time approach, which is inherently flawed and biased, according to Mark Yang, director of fill/finish development for Genzyme. Phuong Nguyen, a senior scientist with Millennium Pharmaceuticals (The Takeda Oncology Company) agrees with this approach. “The quantitative models for these multiple quality attributes can then be used for global optimization of the formulation, leading to more robust formulation development,” she says. Nguyen also notes that depending on the data that are generated from an experimental design, it is sometimes possible to gain some mechanistic understanding of protein stabilization or behavior.

In addition, because multiple variables can be explored at once, fewer formulation studies are required and, therefore, formulation development is more efficient. An added benefit of this efficiency, Yang notes, is the reduced quantity of material needed for formulation development, which can be important early in the development of a biopharmaceutical product given the limited availability of the biologic API. Further, a DoE approach can be particularly useful for combination products that have device attributes that must be considered during formulation development, says Nguyen.


While there clearly are numerous advantages to using a DoE approach in the formulation development of biopharmaceuticals, it is important to bear in mind that there are also limitations to consider with this method.

Two main challenges, asserts LaBrenz, include the fact that sampling of an adequate design space is often difficult and there is an overwhelming amount of data that is generated with factorial design. Yang agrees that the typical subset of critical quality attributes of the formulated product that are assayed in a DoE study may not be comprehensive enough to cover some of the quality changes that can occur. Nguyen also warns that the models used for DoE formulation studies may include statistically significant parameters that may not be of any importance, such as when the resulting change from an input parameter range is within the error of the method or is not large enough to have a real effect.

In addition, Yang notes that the API material used in DoE studies comes from one or possibly a few selected primary production lots that are not necessarily completely representative of later production lots. “As a result, the conclusions drawn based on DoE formulation studies can be biased to some degree,” he says.

LaBrenz believes that the challenges of a limited design space and the management of large quantities of data can be ameliorated with the adoption of high-throughput screening (HTS) techniques that provide both full design space coverage and the ability to collect data in spreadsheets and, eventually, databases.

Even with the use of HTS, however, implementation of DoE for formulation development can be time consuming and resource intensive and can translate into more extensive experimentation than planned, according to Nguyen. “It is a challenge to balance the number of experiments required for a statistically robust DoE study with the available supplies, personnel, resources, and time,” she says. In addition, user training is a must, according to Yang. “DoE study design and data processing requires an understanding of statistics theory and models, which can be challenging for many new users,” he comments.


In most DoE formulations studies, data related to the critical quality attributes and the stability of the API, such as the protein melting temperature, secondary or tertiary structure, or other biochemical/biophysical characteristics, are generated. The ultimate goal for formulation development is to maintain the API in a stable state with respect to both structure and function during processing and storage, according to Yang. Nguyen points out that all of the previously mentioned parameters may serve as indicators for a stable state.

It is also important to reduce the data to single-value results as often as possible, such as the percent monomer or aggregate as determined using size exclusion chromatography-high performance liquid chromatography (SEC-HPLC), or the percent purity. For spectral data from characterization assays, Janssen calculates the Center of Spectral Mass Wavelength (or Mean Center Mass), which allows the creation of a relative stability profile for a given spectrum-based assay. “This single-point, continuous, data-point strategy is readily testable using most statistical methods,” LaBrenz explains. In addition, Nguyen notes that the generated stability data can be reduced down to a reaction rate constant or an output parameter used to develop statistical models. “Overall,” she summarizes, “data on quality attributes are generated that will provide an understanding of how the excipient or formulation within the design space affect these attributes.”

Because DoE studies lead to the production of large quantities of data, it is important to ensure that all of the data that are collected are actually relevant. “A thorough understanding of the API and desired formulation characteristics is necessary before initiating a DoE study,” says Yang. “With such knowledge, a scientist can make sound scientific judgments and consider the potential impact of new factors or excipients when designing a DoE study.”

LaBrenz adds that developing the proper experimental design space before setting up DoE experiments ensures that the parameter critical for the stability of an API is identified. More specifically, conducting a screening DoE to determine which product quality attributes (and the corresponding output parameters used to represent them) are relevant in the design space is helpful, according to Nguyen. Accelerated stability studies can also be performed to determine relevant output parameters.

Another key to generating appropriate and relevant data is to make sure that normal-distributed data, obtained either directly or after transformation, are used. If there is a major process change, it is necessary to evaluate and understand any impacts on the protein and the formulation, according to Yang, which may mean conducting comparability or bridging studies.

 For DoE studies to be useful, the generated data must not only be relevant, but manageable. There are different approaches to addressing this problem.

The solution for LaBrenz is to use an open, read-only database that can be shared between multiple groups, such as preformulation, formulation, and analytical development groups, so that each unit can focus on particular aspects of interest in a DoE. “While a formulation scientist needs to know where the most stable space for an API resides, an analytical chemist may be more interested in the variability and reproducibility of results, both of which can be obtained from a well-designed DoE,” he says.

Nguyen remarks that using software to automate data collection and extraction of the relevant output parameters for statistical analysis is important. She also stresses that having an understanding of which output parameters to collect and limiting the excipients examined to a subset of approved parenteral excipients can reduce the amount of data that must be analyzed.

Training on data processing is also crucial, regardless of what approach is used. LaBrenz uses many different tools depending on the level of complexity required for a given project, and often the choice of software is determined by collaborators. “It isn’t the software package that actually matters. It is all of the extra training to develop my applied statistics skills, including six-sigma training and seminars, that helps me on the job,” he states.


  Cynthia A. Challener is a contributing editor to 

Defining critical parameters and processing large quantities of data can be a challenge.

DoE Provides Benefits, but Preparation Is Necessary

Following the recall by FDA in 2008 of heparin due to contamination of raw material from China, the pharmaceutical industry realized that greater management and control of the supply chain was needed to properly protect patient safety. The result: creation of the Rx-360 Consortium, an industry group focused on sharing information and developing processes to enhance the integrity of the healthcare supply chain that complements the efforts of regulatory agencies. Five years later, Rx-360 has established itself as a resource for the industry by providing valuable information and tools related to supply chain security and quality. The organization is currently working to expand its efforts to pharmaceutical markets in developing regions of the world.


  The biggest success for the Rx-360 Consortium, according to Rx-360 chair Brian Johnson, who is also senior director of supply chain security at Pfizer, is that the group is viewed as an industry thought leader in supply chain safety and patient safety. He notes that the group has established a very effective mechanism for raising awareness of counterfeiting, product diversion, theft, and other harmful activities and is now seen as a key source of supply chain intelligence. In addition, Rx-360 has published numerous white papers and developed other supply chain security tools that it shares for free on its 

. The Consortium also hosts free training webinars on key supply chain security topics. “Our goal is to help everyone in the supply chain increase their ability to protect the integrity of the supply chain,” Johnson says.

A key accomplishment for the group has been the development of the Joint Audit program, which allows multiple companies working with the same business partner to participate in a standardized audit without sacrificing product or process confidentiality. “The program is designed to significantly reduce audit costs, standardize the audit scope, expand the number of audits conducted, and ultimately reduce supplier audit fatigue while maintaining a high quality standard,” observes Johnson. “With this program,” he adds, “it is possible for pharmaceutical companies to more effectively allocate their limited resources and achieve greater reach into the supply chain.” In June 2014, Rx-360 announced a strategic partnership with BSI Supply Chain Solutions to streamline the audit process and ensure supplier compliance with quality and security standards through verification audits.

These various initiatives are, however, only part of the reason Rx-360 is viewed as a thought leader by both industry members and regulators, according to Johnson. The Consortium’s commitment to sharing and communication of information is just as crucial. “Rx-360 was founded on a culture of transparency and openness, and our activities are all driven by the need to ensure patient safety. It is necessary to be inclusive, transparent, and open, and to communicate about all issues so that problems can be identified and resolved. Patient safety is not a competitive advantage,” he asserts.


  Recent projects either completed or initiated by Rx-360 cover numerous aspects of supply chain security and involve various approaches to providing information and assistance. White papers made available on the website are written by subject-matter experts and provide tips and suggestions for dealing with challenging issues. One recent example focuses on responding to the problem of cargo theft, which has been an issue for pharmaceutical manufacturers in Italy. The thefts generally involve organized crime and hijacking. The white paper discusses steps that companies can take to reduce their exposure to these types of incidents. Also in 2014, a white paper describing tools and techniques for managing the supply chain and maintaining supply chain integrity was published. According to Johnson, two to three such papers are prepared each year.

Back in the US, Rx-360 pursued an educational campaign targeting the medical community on why purchasing drugs from known, validated sources is critical. Counterfeit, substandard, and diverted medicines represent a serious patient safety risk and can enter the legitimate supply chain via healthcare providers purchasing from unknown sources, according to Johnson. The issue was clearly highlighted when fake Avastin was found in the United States on two separate occasions in 2012. “Education and awareness within the medical community about safe buying practices is an important part of the battle against fake medicines,” he notes. Also in September 2014, the Consortium announced its support for FDA’s “Know Your Source” campaign, which encourages healthcare professionals to verify the source of their prescription drugs and utilize suppliers licensed in-state.

In Africa, Rx-360 has been working to provide information on effective pharmaceutical distribution practices. “It is often a significant challenge to get safe medicines to people in need in Africa due to the lack of proper distribution infrastructure and awareness of the storage and handling needs of many drugs. We have developed materials on good distribution practices (GDP) and are providing them to pharmaceutical companies and distributors through a series of GDP Workshops in Africa in order to help address the shortcomings and increase the likelihood that key medicines will be delivered safely,” he explains.

In the serialization space, Rx-360 is focusing on issues that are not being addressed by other groups. In particular, a working group has been established to look at potential data architectures for serialization that will enable the smooth movement of drug products from one market to another. The Traceability Data Exchange Architecture Work Group, established in August 2014, is a collaborative work group set up to support serialization and track and trace legislation that is evolving globally. “The focus of the group,” says Johnson, “is to develop conceptual models for the interoperable exchange of information needed to comply with global regulations.” The group is expected to have a white paper available by the end of 2014 for discussion at industry forums. The workgroup is tri-chaired by Lloyd Mager of AbbVie, Peggy Staver of Pfizer, and Brian Rezach of Actavis.


  With the numerous successes that Rx-360 has achieved in its first five years, Johnson believes the group is positioned to expand its efforts in a variety of ways. He first notes that globalization has led to increasing complexity in the supply chain, with raw materials manufactured in one part of the world, drug substance produced in another, final drug products packaged in a third and then distributed globally. “As a group, Rx-360 was initially focused on the US and European Union, but we do realize that emphasizing markets that are already highly regulated will not solve the problem. Therefore, we are increasing our efforts around the world, with the ultimate goal of covering the entire globe,” comments Johnson. 

The first initiative was launched in 2013 when the Asia Working Group was established in China. This group is doing a lot of the same work that Rx-360 is doing in the US, but from an Asia/China perspective and with the hopes of influencing supply chain integrity in the region, according to Johnson. The Consortium is also in the process of establishing a similar working group in India. Rx-360 is in discussions with a number of stakeholders and is building momentum for achieving the critical mass needed to formally launch the group.

The Consortium is also focused on expanding participation in the organization by groups involved in the pharmaceutical supply chain other than drug manufacturers and their direct suppliers. “There are a lot of people involved in the supply chain, including distributors, carriers, service providers, and others, and we want to engage with all of these groups in order to be able to evaluate supply chain security issues in a truly holistic manner,” Johnson states.

Driving volume in its Joint Audit program is another major goal for Rx-360. With a larger number of companies participating in the program, the number of available audit reports will increase. As a result, pharmaceutical manufacturers will be able to rely on the joint audit program for lower risk audits of reliable suppliers, and focus their resources on higher risk sources, according to Johnson. “We want this program to be as successful as possible for the industry, and thus we are committed to increasing the volume of audits,” he says.

Finally, Rx-360 is also looking to expand its user base and leverage its knowledge of supply chain security for the benefit of related industries. One of the first efforts is the Medical Device Initiative, which was launched in May 2014 to identify and address the supply chain quality and security needs of medical device companies. The Medical Device Working Group was created to integrate the goals and priorities of the medical device industry into the existing supply chain security programs of Rx-360, according to Johnson. 

Supply chain security and quality group Rx-360 driven by patient safety.

Mission: Close Gaps in the Supply Chain

Due to its high ionization potential, electron affinity, and electronegativity, fluorine is a highly electron withdrawing substituent. In addition, fluorine-carbon bonds are much stronger than carbon-hydrogen bonds. Consequently, incorporation of fluorine atoms into APIs results in changes in polarity that often affect not only the reactivity of neighbouring groups, but also the acidity, basicity, protein binding affinity, and lipophilicity of these molecules. As a result, fluorination can significantly impact the bioavailability of drug substances. Introducing fluorine into complex intermediates can be a challenge, however, and generally requires special expertise. Finding contract manufacturers with GMP fluorination capabilities can, therefore, also be a challenge.


The initial reagents used for the fluorination of organic compounds, such as potassium fluoride (KF), hydrogen fluoride (HF), antimony trifluoride (SbF

) itself, generally require harsh reaction conditions. These reagents are also typically gases that are aggressive. Some are also explosive and/or toxic.

Although still widely used in many industries, their application to API synthesis has been somewhat limited. Reagents that are more commonly used in the pharmaceutical industry still present handling issues. They also tend to be costly and often are not appropriate for the introduction of fluorine in the presence of functional groups. Such reagents include poly[4-vinylpyridinium poly(hydrogen fluoride)], 1-fluoro-2,4,6-trimethylpyridinium triflate, cyanuric fluoride, and tetrabutylammonium hydrogen difluoride.


The search for less aggressive, easy-to-handle, nontoxic fluorinating reagents has been underway for many years. Initially improved reagents such as (2-methoxyethyl)aminosulfur trifluoride (Deoxo-Fluor) and 1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor), which are both from Air Products, have been more widely used in API synthesis. Diethylaminosulfur trifluoride (DAST) is another common reagent.

Deoxo-Fluor and DAST are nucleophilic fluorinating reagents that have improved properties compared to the harsher chemicals mentioned previously. They rapidly deoxofluorinate alcohols, aldehydes, and ketones under mild conditions to yield the corresponding fluorinated compounds with high efficiency and selectivity. The reaction involves the nucleophilic replacement of oxygen with fluorine, with hydroxyl groups converted to C-F substituents and carbonyl groups to CF2 moieties.

Selectfluor, also known as F-TEDA-BF4, is a general-purpose, site-selective electrophilic fluorinating agent that rapidly fluorinates a wide range of organic molecules under mild conditions with high efficiency and selectivity and, in many cases, has been used as an alternative to FClO

OF. Recent examples of reactions achieved with Selectfluor include the iron-catalyzed free radical Markovnikov hydrofluorination of unactivated alkenes (1) and the synthesis of monofluorinated benzylic substrates (2), the silver-catalyzed decarboxylative fluorination of aliphatic carboxylic acids (3), and the chemoselective, metal-free introduction of a fluorine atom into various aromatic and aliphatic compounds (4).


More recently, solid fluorinating reagents have been introduced to the market: Xtal-Fluor-E from Manchester Organics (in partnership with OmegaChem) and Fluolead from UBE Industries.

Xtalfluor reagents include (diethylamino)difluorosulfonium tetrafluoroborate (Xtal-Fluor-E) and difluoro(morpholino)sulfonium tetrafluoroborate (Xtal-Fluor-M). These fluorinating agents are easily handled crystalline solids with enhanced thermal stability (i.e., higher decomposition temperatures with lower exothermic heat and higher onset temperatures for self-accelerated decomposition) (5). They do not generate free HF and are compatible with glass equipment. In addition, they generally produce fewer elimination side products, and thus provide greater selectivity than more traditional nucleophilic fluorinating reagents, such as DAST and Deoxo-Fluor (6, 7).

Fluolead (4-tert-Butyl-2,6-dimethylphenylsulfur trifluoride) is also a crystalline nucleophilic fluorinating agent useful for deoxo-fluorination reactions. Its reactivity is comparable to that of SF

, but it has high thermal stability, can be handled in air, does not fume, and reacts slowly with water.  In addition to converting alcohols and carbonyls to CF and CF

 groups, Fluolead converts carboxylic acid (COOH) substituents to trifluoromethyl (CF

) groups and can fluorinate sulfide compounds (8-11). While these reagents are easier and safer to work with, their higher cost can still pose a challenge for commercial-scale use.

I) has also risen recently, according to Anthony Nigro, manager of product development for Halocarbon Products. Conventionally, the trifluoroethyl group has been introduced using trifluoroethylamine, which is a weak base that requires strongly acidic reaction conditions and thus can only be used for substrates that can withstand exposure to strong acids. Trifluoroethyliodide is much more reactive, and this reagent can even be used in later stages of pharmaceutical syntheses. “Convergent synthetic strategies, which require the introduction of fluorine substituents much later in the synthetic sequence, are gaining in popularity, as are direct fluorination techniques. This trend is one of the drivers for the interest in trifluoroethyliodide,” notes Nigro. He adds that the iodide does not require any special equipment or handling and is a cost-effective reagent.

I include the Pd-catalyzed 2,2,2-trifluoromethylation of organoboronic acids and esters (12) and the synthesis of β-trifluoromethylstyrenes via a domino Heck coupling reaction (13).


While the search for fluorinating reagents that are inexpensive, safe, and mild for use with complex intermediates in large-scale manufacturing processes continues, pharmaceutical companies must continue to achieve fluorination using currently available reagents that meet the cost and reactivity constraints of their systems. In the past, it was common for drug manufacturers to perform these types of reactions in-house, but that is not the case today, according to Nigro. “Most pharmaceutical companies have streamlined their operations and generally outsource the production of intermediates that require specialized chemistries and synthetic techniques. Fluorination often falls under this category given the physical and chemical characteristics of most cost-effective fluorinating reagents,” he explains.

There are few contract manufacturers with expertise in fluorination chemistry and not all of them can produce pharmaceutical intermediates under GMP conditions. “There is a need in the marketplace for contract manufacturers that have the necessary skills and expertise to both perform fluorination chemistry and meet GMP requirements,” says Nigro.

. 134 (33), 13588-13591 (2012).
  2. 	S. Bloom et al., 

15 (7), 1722-1724 (2013).
  3. 	F. Yin et al.,

. 134 (25) 10401-10404 (2012).
  4. 	Y. Amaokaet al., 

, Accessed 8/21/2014.
  6. 	A. L’Heureux et al.,

. 75 (10) 3401-3411 (2010).
  7. 	A. L’Heureux et al., 

 153 (1) 57-60 (2013).
  8. 	T. Umemoto et al.,

. 132  (51) 18199-18205 (2010).
  9. 	R. P. Singh and T. Umemoto, 

 76 (9) 3113-3121 (2011).
  10.	T. Umemoto and Y. Xu, “Substituted Phenylsulfur triflouride and other like fluorinating agents”, US patent 7,265,247 B1, Sep. 2007.
  11.	T. Umemoto and R. P. Singh, “Substituted Phenylsulfur triflouride and other like fluorinating agents”, US patent 7,381,846 B2, June 2008.
  12.	Y. Zhao and J.Hu, 

 51 (4) 1033-1036 (2012).
13.	G.A. Olah et al., 

Fluorination can significantly impact the bioavailability of drug substances, however, safer fluorinating reagents and access to GMP fluorination capabilities remain challenges.

GMP Fluorination Challenges Limit Use in API Synthesis

CPhI is buzzing with talk of new investments, expansions, and company rebranding. For instance,  in September 2014 SGS completed a new lab in Carson, California that will offer microbioligical testing and bioanalytical services to biotech companies in the region. The company is also constructing a new, state-of-the-art QC lab outside of Paris and is expanding its laboratory in Shanghai with no bioanalytical capabilities, including cytotoxicity and endotoxin testing, cell-based assays, and others.

Hovione, meanwhile, has changed its logo to reflect the fact that it now has capabilities in both chemistry and biotechnology. The company is  celebrating both 10 years of commercial spray drying and the largest installed capacity for commercial GMP spray drying. Hovione will also be expanding its Hovione New Jersey manufacturing site, which has capabilities in cryogenic chemistry, hydrogenation, fluorination, and the production of highly potent APIs.

To reflect its responsiveness to customer needs, Dr. Reddy's CPS has introduced a new logo and tag line -"The Power of Now." In addition, to ensure that it is aligned with customer needs,the company has hired a new head of R&D and a new North American Manager and appointed and created a new business development position in Asia. Key technologies for Dr. Reddy's CPS include chiral chemistry, pegylation technology, continuous processing, and the production of steroids and highly potent compounds, including drug substances and formulated products at both development and commercial scales.

New investments, expansions, and company rebranding are discussed at CPhI.