Public interest in attaining or maintaining health with “natural” remedies has steadily increased during the last few decades. The demand for phytopharmaceuticals, otherwise known as plant or herbal drugs, to treat disease has become a worldwide phenomenon. In Europe, the market for botanicals is well developed and involves prescription sales in some countries. China and Japan also have long traditions of using herbal drugs. In the U.S., interest continues to rise as more Americans choose alternative medicines and self-treatment approaches for their health.
The herbal supplement product industry consists of both large and small companies. All companies have been impacted, to varying degrees, by deficiencies in knowledge and quality control guidelines for herbal drugs. Some companies have hurt themselves by releasing poor quality products, such as supplements lacking the listed amount of labeled ingredients or products containing undesirable contaminants. These product quality problems in the supplement industry have made the marketplace vulnerable to attack from consumer advocates and have presented pharmaceutical companies with an ideal market opportunity. Thus, a pharmaceutical model or standard applied to the natural products market can position companies above the present competition.
Scientific studies and clinical trials to support claims of efficacy will be essential for the long-term success of any herbal or natural product. Research will separate the winners from the losers. To increase the likelihood of success, companies must invest in the necessary science to back up their products and protect their position in the market. Performing clinical studies, patenting products and developing proprietary or trademarked products are some of the best ways to achieve market protection. Relaying information to doctors and other health care professionals helps to further strengthen market position.
Natural Products Contract Services
Some pharmaceutical companies have already pursued the op-portunities that the natural products movement presents. How-ever, pharmaceutical companies have limited experience with natural products chemistry. Their expertise tends to lie with synthetically designed drugs developed in a highly controlled environment. Natural products chemistry is quite different from traditional pharmaceutical work, both from a chemistry and regulatory standpoint. The discipline of natural product chemistry re-quires specific expertise not typically found in a pharmaceutical company. Consequently, pharmaceutical companies have found it advantageous to develop working relationships with contract laboratories that specialize in natural products chemistry.
As we know, the use of contract laboratories for specialized projects is commonplace in the pharmaceutical industry. Increased pressure on pharmaceutical companies to control costs while increasing productivity and reducing the time to market for new products has fueled this trend. In addition, startup or virtual companies with limited financial resources to support the research infrastructure use contract service providers to develop their products.
Partnerships and alliances between large pharmaceutical companies and smaller natural products companies help to expand current business by broadening product lines and increasing distribution channels. Pharmaceutical companies can leverage their financial resources with the core competencies of the natural products contract laboratory. To make this relationship work, mutual respect between the pharmaceutical and natural products scientists is necessary to encourage communication and creativity. To minimize risks, it is best for the pharmaceutical company to use a company that has the appropriate resources, technical knowledge, cGMP experience and proper safety programs in place.
Product and Process Development
The selection, collection and taxonomic identification of the marine/botanical material are the first steps in carrying out a natural drug project. Marine/botanical selection should involve a comprehensive search of the literature for marine/ botanical facts, biological activity, clinical therapeutics and toxicology. Once the marine/botanical species is chosen, it is im-portant to control the source of the raw material. The quality of botanical raw materials collected from different areas and even the quality of individual plants can be variable. Environmental conditions such as climate, soil type, pests and time of harvest can also impact raw material quality. Consequently, cultivation under standardized and controlled conditions is desirable.
In most cases, a pharmaceutical company will purchase the raw material from a supplier. For botanical raw material, a company needs a well characterized material with an established supply chain. The herbal raw material can be a specialty item, USP/NF material or a commodity item. Regardless of whether the supplier is a domestic or foreign company, it is important to determine that the supplier can provide details on how the product was processed, along with a complete certificate of analysis with evidence of written and validated methods. The quality of certificates of analysis varies across suppliers, so it is important to compare and ask questions. Raw material needs to be traceable, measurable and of pre-determined acceptable quality. Issues that need to be considered include raw material characterization, product uniformity and product shelf-life.
Raw material is authenticated using macroscopic, microscopic, organoleptic and chromatographic techniques. The use of different marine/plant species and/or different parts of the plant (root versus aerial, for example) can result in significantly different pharmacologically active components. Crude raw material handling such as drying, crushing, storage and preservation conditions need to be considered to ensure product reliability. Common pharmacologically active components of interest consist of the following class of compounds: alkaloids, flavonoids, fatty acids, steroids and terpenoids, to name a few. These active components need to be isolated from the plant matrix.
Natural product isolation is generally accomplished in three stages: (1) extraction, (2) fractionation and (3) purification. It is important to realize that the amount of work required for natural product isolation increases exponentially with the degree of purity desired. Experience is key to finding the most efficient and economical means for isolating compounds. Extraction of a natural compound depends primarily on its solubility, stability and functional group characteristics. Precautions need to be taken to avoid decomposition, side reactions or rearrangements of the compound(s) during the extraction process. Several isolation techniques can be employed, including liquid-liquid extraction, liquid-solid extraction, process scale chromatography, precipitation, filtration and crystallization. When isolating one or more specific compounds, it is necessary to keep track of the compound(s) through the entire process, including the stability and activity of the compound(s).
There are several development challenges for herbal product manufacturing. There is the possibility that, by isolating certain components from the marine/botanical matrix, health benefits not yet discovered in the original material might be lost. In going from lab bench scale to production scale, it is essential to determine the level of productivity along with the stability and activity of the pharmacologically active compounds. Practical points to consider are the number of lots (single or multiple lots) that will be produced annually, the scale of production, the complexity of unit processes (blending, granulation, fill), the reproducibility of the final product (blend, finished product, batch-to-batch) and the demonstration of reproducibility.
Some form of process verification and testing needs to be conducted to assure that the product can be made reproducibly. Product content uniformity for low-dose ingredients, at less than 5% (w/w%) final dose form, is difficult to achieve. Key variables effecting this are the complexity of unit processes, the physical properties of the ingredients and facility controls (humidity and temperature). One way to assess product content uniformity is by testing five to ten composite samples evenly distributed throughout the manufacturing run.
In choosing a contract manufacturer, consider the types of products they make at their manufacturing site. The vendor may be involved with a single type of product or several types of products — some combination of a drug, food or dietary supplement. It is important to determine which cGMP they apply to their facility and to review audit reports.
Once the choice of a manufacturer has been made, accurate plans are needed that detail the responsibility of both partners and the expected due dates for project completion. Projects may be short- or long-term. Project plans need to take into account some or all of the following issues: production size requirements, process steps and controls, equipment needs, capital expenditures, material sourcing, analytical methods, transfer and validation strategy, regulatory filing requirements, approval dates, product launch and the contacts at client and contractor sites.
Natural Products Analysis
Analytical experience and state-of-the-art instrumentation is a key component for the successful development of natural products projects. When dealing with natural products, scientists must contend with a complex sample matrix that contains similar chemical compounds. The pharmacologically active compounds are usually present in small amounts. With the increased development and use of natural drug systems, it is necessary to develop highly sophisticated analytical methods to ensure that the natural drug is uniform and pure. It is critical that the integrity of the natural drug components are preserved during manufacturing and that the resulting natural drug product does not contain toxic impurities.
One of the difficulties in natural drug systems is overcoming the unique analytical challenges they present. The analytical approach is different from small-molecule drugs. Creative solutions are required for the full characterization of the product. There are two primary ways to characterize the product: (1) chemical assays (TLC, HPLC, LC/MS) and (2) bioactivity assays (microbial, cellular, metabolic, enzymatic, gene expression).1
Traditionally, herbal dietary supplements and pharmaceutical analyses have used thin layer chromatography (TLC) and/or high performance liquid chromatography (HPLC) with single wavelength or photodiode array detection. These techniques can be used for quality control purposes once a validated method has been established. However, the complex matrices of herbal products require more specific, selective and sensitive methods to identify and characterize the marker compounds.
The coupling of mass spectrometry with liquid chromatographic separations (LC/MS) has expanded the capabilities of compound identification in these complex matrices. Electro-spray ionization (ESI) mass spectrometry has been a valuable tool for the determination of the molecular weight of compounds. In-source collision-induced dissociation also provides some structural information. More recently,ion trap mass spectrometry has allowed for direct infusion MS/MS and MSn analyses, and LC/MS/MS analyses when coupled with HPLC separations. The employment of the spray ionization techniques for LC/MS and direct infusion MSn have been utilized for molecular weight determination and structural elucidation in the support of custom synthesis, pharmaceuticals, herbal dietary supplements, impurity identification and other novel applications.
These techniques are ideal for solving client problems. For example, LC/MS was used to verify the presence of trace quantities of the marker compound hyperforin from St. John’s Wort in a complex product formulation to substantiate a manufacturer’s label claim. In another case, MS3 was used to determine the non-linear sequence of a tetrasaccharide ob-tained from the hydrolysis of a natural product extract. These tools have been used to detect impurities or to identify adulterants in product material. They can rapidly and simply perform QC analyses of marker compounds. These techniques can be applied to determine the structures of natural drug compounds in support of developing synthetic routes to these compounds or for synthesizing natural product derivatives. For the development of primary standards, NMR is employed as an alternative means of identification to characterize the stereochemistry of purified natural compounds.
Bioassays are used to determine the biological activity and to determine the efficacy of formulated product. Several types of assay tests are available, including enzymatic, cellular, microbial, metabolic and gene expression. The challenge is choosing the test that will most accurately represent the biological activity of interest. Natural products contract laboratories usually do not have the in-house expertise to perform these tests. They routinely outsource this work. Some contract laboratories have developed contacts and relationships with companies specializing in bioassays, in order to have access to bioanalytical consulting and testing for a product.
Analytical Methods Validation
High standards are necessary to ensure that a high-quality product gets to the consumer. High product quality drives brand strength, which is based on product integrity, safety and efficacy. A testing program should include instrument IQ/OQ, calibration, documentation, review, approval and archival processes for methods, data and studies. Presently, there are few industry standardized methodologies for herbal products testing. The United States Pharmacopeia (USP) has developed monographs for some of the more common herbs; however, these methods are limited in the degree to which they have been validated. The Institute for Nutraceutical Advancement (INA) is an industry-sponsored program that has 12 analytical methods that have been validated by several laboratories for some of the more popular botanicals. The American Herbal Pharmacopoeia (AHP), a not-for-profit educational corporation, currently has 10 critically reviewed monographs that include validated analytical methodology.
The degree of methods validation required depends on the type of herbal product. Some herbs can be well characterized ingredients that are tested using monograph methods. Others may involve new active herbal ingredients that are not well characterized, not measured directly and not tested using monograph methods. Documented methods that have an established range of accuracy, precision and specificity are essential. An appropriate level of test method validation is needed to ensure that measurements are accurate and reliable. Testing must be conducted on raw material, finished product and in-process samples, as appropriate, to measure consistency and quality. Complete testing of the herbal product consists of raw materials, process verification, product release and packaged product stability testing.
Herbal Drug Product Testing
Dissolution studies are used to determine the best formulation to release the natural drug in a pre-designed manner for proper delivery. Nutraceuticals can be formulated in a wide variety of dosage forms, ranging from tablets and capsules to nutritional bars and drink mixes. The bioavailability of an orally administered active ingredient is dependent on the excipients used in the final product. Pre-formulation and formulation development studies are needed for new herbal drug products to ensure that the active is stable and bioavailable. Plant extracts contain not only the desired pharmacologically active compound, but may also contain solubilizers, stabilizers, chelating agents and buffering agents, which can impact bioavailability. Different formulations of the same botanical ingredients can yield differences in bioavailability. A proprietary formulation that yields enhanced bioavailability can provide a competitive advantage for a company.
Since manufacturing processes can impact the stability of the final product, stability issues need to be tackled. Stability tests must be conducted to establish initial shelf-life estimate of expiry period for 100% of label claim. Product shelf-life or expiry period can be initially predicted by using accelerated conditions (40°C/75%RH) or by using data from similar formulations. Target and release limits for a desired shelf-life of 24 months need to take into account ingredient potency losses (stability) and analytical testing and manufacturing process variability. Confirmation of initial predictions is required by using real-time packaged product stability studies at 25°C/ambient.
Stress testing can be performed to determine the inherent stability of the actives. Forced degradation studies under hydrolytic (neutral, acidic and alkaline), oxidative and photolytic conditions can be used to determine the pathway for degradation. In some cases, the pathway can be predicted based on the functional groups present or by the structure of the active. Identifying the degradation by-products that result from harsh conditions allows one to develop a specific stability-indicating analytical method to monitor the stability of the product properly.
Safety concerns require testing be done to ensure the absence of contaminants such as heavy metals, pesticides radioactivity, bacteria or fungi. If contaminants are detected at unacceptable levels, further processing of the material is required to remove these impurities. The removal process needs to be validated to demonstrate that acceptable levels have been achieved. The challenge is to remove the undesirable contaminants while leaving the active components intact. A company can gain market advantage by developing validated proprietary purification processes that allow it to be the sole source provider of purified extract material, as was the case with ginseng contaminated with quintozene.
Under the FD&C Act, the FDA is responsible for enforcing tolerances established by the EPA for amounts of pesticide residues that may legally remain on food. Due to the lack of clear guidance, herbals are often treated as foods in terms of pesticide tolerances. Despite the lack of toxicological data, the FDA set a zero tolerance levels for those pesticides for which no tolerance level is set. (In the case of quintozene, this equated to a level of 10PPB for each pesticide component). Guidelines in the USP 24/NF 19, First Supplement, Articles of Botanical Origin <561> are based on EU requirements and do not hold true for herbals in the U.S. Analytical method guidelines listed in the FDA’s Pesticides Analytical Manual (PAM) Volume 1, which contains multiresidue methods (MRMs) used by the FDA in enforcing pesticide tolerances, must be followed.
Microbial contaminants are likely to be present in herbal products that have not been properly handled, especially at the crude material stage. Microbiological testing is performed according to USP methodology on raw materials and finished products.
Botanical plants often concentrate metals from the soil via uptake through their root systems. Heavy metal testing for botanicals is also not well defined. Consequently, USP methodology is often employed to determine the amount or presence of metal impurities. The USP Heavy Metals <231> test provides a method to demonstrate that the content of metallic impurities that are colored by sulfide ion does not exceed the heavy metals limit specified in the USP monographs for the herbal of interest. The heavy metals limit is usually established at 0.001% or 10PPM. The target list for metals includes bismuth, arsenic, antimony, tin, cadmium, silver, copper, molybdenum, lead and mercury. The test often requires an extensive digest procedure that is apt to lose volatile metals such as mercury. Heavy metal testing is best achieved by using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), which can achieve detection limits that are many orders of magnitude lower than the 10PPM USP and can eliminate most matrix interference difficulties.
Regulatory Concerns
The regulatory issues surrounding herbals are currently under debate. The debate over the level of regulation stems, in part, from the interpretation of the status of the active ingredient. Does the active have inferred activity with no clinical studies or is it well characterized and clinically studied? Some argue that the FDA should require manufacturers to comply with cGMPs for food products, since herbals are sold as foods. Others argue that they should conform to the same quality regulations as generic drugs and OTC pharmaceuticals. A regulatory affairs staff that can provide advice or guidance regarding key areas in a natural products project is necessary to minimize regulatory risks.
The Dietary Supplement Health and Education Act of 1994 established a new framework for assuring the safety of dietary supplements, with the burden of proof resting with the federal government. DSHEA defined “an herb or other botanical” as a dietary supplement. DSHEA allows for nutritional support statements without obtaining pre-marketing authorization from the FDA. However, manufacturers are required to have substantiation of label claims. Label claims include a nutritional facts box and structure-function claims. For new dietary ingredients (not marketed in the U.S. before October 15, 1994), the manufacturer must provide the FDA with evidence of safety. The act also required the formation of an executive level commission on Dietary Supplement Labels and an Office of Dietary Supplements within the NIH, as well as the FDA Center for Food Safety and Applied Nutrition. Dietary supplements were no longer subject to pre-market safety evaluations required of other new food ingredients or for new uses of old food ingredients.
In addition to laying the foundation for a regulatory framework for dietary supplements, DSHEA provided the FDA with the authority to promulgate cGMP regulations for supplements and required that they be modeled after food cGMPs. This provision has lead to the most significant and important issue facing the herbal industry, which is the Advance Notice of Proposed Rulemaking (ANPR) for cGMPs for the dietary supplement industry. The ANPR for dietary supplement cGMPs attempts to bridge the gap between food and pharmaceutical cGMPs to ensure consistency and quality. It represents an increased effort based on food cGMPs and has some similarity to drug cGMPs insofar as it calls for a Quality Control Unit. It is open to interpretation and provides more flexibility with which to operate than do pharmaceutical cGMPs. Nevertheless, it requires more resources to bring a product to market than under food cGMPs. Other guidance documents or approaches that can be applied to herbal product manufacturing include the Hazard Analysis and Critical Control Points (HACCP) and the USP Manufacturing Practices for Nutritional Supplements, USP 24/NF 19 <2750>.
When cGMPs for dietary supplements go into effect, manufacturing operations will need to define and refine their manufacturing practices. To ensure regulatory approval, time will need to be spent upfront to ensure that the production process will be cGMP compliant. Operations will need to validate equipment, systems and utilities and have analytical support from QC. Although the regulatory future will depend on the final rule for dietary supplement cGMPs, the overall goal of any operation should be to assure that product quality and potency is maintained over the shelf-life of the product, that quantitative labeling represents the product, that label claims are truthful and not misleading and that consumer safety is upheld.
Pharmaceutical companies that are already familiar with drug cGMPs should have little trouble adjusting to this new regulatory environment. Depending on the clinical stage, cGMP requirements will vary, but should consist of a continuum of increasing documentation, requirements and validation, from pre-clinical to Phase III trials. Areas that need to be addressed include facilities, equipment, personnel and training, raw materials, packaging materials, production controls (process validation), laboratory controls (methods validation), packaging and labeling. Standard operating procedures will need to be developed for the holding and distribution of finished product, for change control/investigations and for records and reports.
Contract Provider Selection and Interaction
Selection of a contract laboratory is an uncertain process. It is somewhat akin to finding a spouse. The goal of the selection process should be to minimize risk and maximize comfort level. Sponsors must look for a company that is focused on customer needs, owns and solves customer problems, builds strong customer relationships at all levels and capitalizes on customer challenges as company opportunities. The provider should have the appropriate regulatory knowledge and experience, as well as technical and scientific expertise. As a start, detailed information about a company can usually be found on its web site. Industry organizations can also assist in locating candidates.
Initial discussions can involve nonproprietary information related to each participant’s qualifications and experience, to the product concept and its developmental stage and sponsor expectations. If the contract provider seems like a good fit, a confidentiality agreement should be signed in order to obtain more detailed information. For extensive projects, early negotiations should include discussions related to long-term facility availability. With the upfront costs of inspections, contract preparations, visits, familiarization of each others systems and the transfer and validation of methods, long-term projects are best.
A site visit is essential in order to investigate the contractor’s facilities and equipment and to assess the personnel and their level of training. Additional points to consider are the contractor’s previous cGMP experience and the number and size of projects requiring regulatory compliance that it has completed. The sponsor needs to determine whether the provider can meet the schedule and project timeline. The last consideration should be price. Con-sider the details needed to complete the project correctly and look objectively at the true costs involved. Cutting corners on price on the front end, by eliminating certain tasks, usually leads to more costs on the back end. Once a decision has been made to work with a provider, be sure to address, in the formal contract, which party owns the technology or inventions.
Project management is key to the success of any major undertaking. A contract laboratory that is customer oriented will be attuned to your needs and expectations — almost like an extension of your own company. Sponsors should be sure to maintain a close, effective relationship with the contract provider, since issues will need to be resolved cooperatively and collaboratively. Weekly updates are advised. Forward thinking is required as products are moved through process development and production toward any FDA approval. Identifying potential problems and addressing them early on during technology transfer and process development is important.
Sponsors must realize that a unique set of skills, equipment and experience is required for work in the area of natural drugs. Projects in these areas are variable and complex. When seeking contract laboratory services in the area of natural products, they should look for a laboratory that is customer-connected, that has expertise in isolating and analyzing natural products and that has a good regulatory track record.
1. We should distinguish between a marker and an active. A marker is a chemical compound that can be assayed, whereas the active is the pharmacologically active form of the compound. A marker may or may not be an active.