United States Pharmacopeia Monograph Research Articles

Review of the pharmacokinetics of French maritime pine bark extract (Pycnogenol®) in humans.

The French maritime pine bark extract Pycnogenol® is a proprietary product from Pinus pinaster Aiton. It complies with the quality specifications in the United States Pharmacopeia monograph "Pine extract" in the section of dietary supplements. Pycnogenol® is standardized to contain 65-75% procyanidins which are a variety of biopolymers consisting of catechin and epicatechin monomeric units. The effects of Pycnogenol® have been researched in a multitude of human studies. The basis for any in vivo activity is the bioavailability of constituents and metabolites of the extract. General principles of compound absorption, distribution, metabolism and elimination as well as specific data from studies with Pycnogenol® are summarized and discussed in this review. Based on plasma concentration profiles it can be concluded that low molecular weight constituents of the extract, such as catechin, caffeic and ferulic acid, taxifolin are readily absorbed from the small intestine into systemic circulation. Procyanidin oligomers and polymers are subjected to gut microbial degradation in the large intestine yielding small bioavailable metabolites such as 5-(3',4'-dihydroxyphenyl)-γ-valerolactone. After intake of Pycnogenol®, constituents and metabolites have been also detected in blood cells, synovial fluid and saliva indicating a substantial distribution in compartments other than serum. In studies simultaneously investigating concentrations in different specimen, a preferential distribution of individual compounds has been observed, e.g., of ferulic acid and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone into synovial fluid compared to serum. The main route of elimination of constituents and metabolites of the French pine bark extract is the renal excretion. The broad knowledge accumulated regarding the pharmacokinetics of compounds and metabolites of Pycnogenol® constitute a rational basis for effects characterized on a cellular level and observed in human clinical studies.

Analytical method development, validation, and out-of-specification investigations for polyethylene glycol

This work was motivated by the United States Pharmacopeia monograph modernization initiative and European directorate for the quality of medicines and healthcare. An out-of-specification (OOS) occurrence prompted OOS investigations for the cGMP (cGMP refers to the Current Good Manufacturing Practice regulations enforced by the FDA) release testing of residual ethylene oxide in polyethylene glycol (PEG) according to the standards detailed within the United States Pharmacopeia/National Formulary (USP-NF) for polyethylene glycol, and the European Pharmacopoeia (Ph. Eur.) for macrogols. During the OOS root cause investigations, we observed a PEG degradant and identified it as methyl formate, which co-elutes with ethylene oxide using the GC (gas chromatography) methods published in current USP-NF and Ph. Eur. for PEGs. To address this, a novel method utilizing static headspace gas chromatography with flame ionization detection (HS-GC-FID) was developed to test various grades of PEGs for the presence of residual ethylene oxide, along with other process related impurities and degradation products. With this new method, ethylene oxide, a known genotoxic impurity and IARC (International Agency for Research on Cancer) Class 1 human carcinogen, can be well resolved from methyl formate, a newly identified and comparatively innocuous degradant derived from PEG. The currently available official compendial methods are unable to separate the specific impurities in PEGs. However, the new GC method presented in this paper has been shown to have a high and unique selectivity, allowing for baseline separations (chromatographic resolutions greater than 1.5) of all related impurities in PEGs, which is a challenging task. Additionally, this method has been found to be stability-indicating based on a forced degradation study. During stress stability study of PEGs involving acid, alkali, heat, light, and oxidation, some other PEG degradants, including formaldehyde, were identified. It is possible that formaldehyde undergoes a disproportionation reaction known as the Cannizzaro reaction, leading to the formation of formic acid and methanol. The formic acid then undergoes an esterification reaction with methanol to produce methyl formate. To the best of our knowledge, this is the first stability-indicating HS-GC-FID method that accomplishes this separation in a single run, and it was successfully validated as per ICH (the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use) guidelines. Therefore, this method is suitable for the conduct of cGMP batch release and stability testing of PEGs in regulated quality control (QC) laboratories.

A stability-indicating, reversed-phase HPLC method for quantification of assay and organic impurities in doxycycline hyclate bulk and parenteral dosage forms.

The aim of this study is to develop a stability-indicating, reversed-phase HPLC method for the quantification of assay and organic impurities (process and degradation) of doxycycline hyclate in a doxycycline injectable formulation. Both the active and dosage forms are officially present in the USP monograph, and assay and impurity methods are provided by separate UPLC techniques, which are highly sensitive to the flow rate and temperature, considering the quality control requirements and user-friendliness. A simple stability-indicating HPLC method with a shorter run time was developed for the simultaneous quantification of assay and impurity. The method was developed using HPLC with a gradient program and a reversed-phase Waters XBridge BEH C8 column (150 × 4.6 mm, 3.5 μm i.d.). Mobile phase A consisted of phosphate buffer (pH 8.5, 25 mM potassium phosphate, 2 mM ethylenediaminetetraacetic acid, and 0.5 ml of triethylamine). Mobile phase B consisted of methanol with a flow rate of 1.7 ml/min, a column temperature of 55°C, a UV wavelength of 270 nm, and an injection volume of 25 μl. Modern research represents a concomitant method for quantifying assay and organic impurities of doxycycline hyclate (active form) and doxycycline for injection (dosage form). The assay and impurity method were validated per United States Pharmacopeia (USP)1225 and International Conference on Harmonization (ICH)guidelines. The retention time of doxycycline and degradation impurity, 4-epidoxycycline, was about 9.8 and 6.4 min, respectively. The linearity range of doxycycline and 4-epidoxycycline was 0.5-150 and 0.5-18 μg/ml, respectively. The percentage of recovery of doxycycline and 4-epidoxycycline was 98.7-100.6% and 88.0-112.0%. Validation of the analytical method demonstrated that the method is suitable, specific, linear, accurate, precise, rugged, and stability indicating for estimating the assay, known and degraded impurities of doxycycline, and doxycycline for injection.

Impurity Purging through Systematic Process Development of a Continuous Two-Stage Crystallization

A methodical development approach was deployed in a novel portable manufacturing (Pharmacy on Demand) unit to purify ciprofloxacin hydrochloride hydrate within assay, water content, and impurity specifications described by the United States Pharmacopeia (USP) monograph and ICH Q3A(R2) guidelines for new impurities in drug substances. A series of design-of-experiment (DOE) and one-factor at a time (OFAT) experiments led to the optimization and control of a continuous two-stage crystallization that increased both the purity and yield of ciprofloxacin hydrochloride hydrate. Additionally, a statistically significant linear model was derived in batch within a 20 °C range that tracked the level of a difficult-to-purge impurity in stage 1 of the purification. This model was tested in continuous flow and predicted the impurity removal within 5% accuracy. With parametric control of process parameters, determined by optimization and modeling work, continuous flow isolations produced an active pharmaceutical ingredient (API) which had no individual impurities above 0.07%, with an isolated yield of 74%. In addition, acceptance criteria for assay (between 98 and 102%) and water content (between 4.7 and 6.7%) were met per the USP monograph for ciprofloxacin hydrochloride hydrate for the first time in the novel POD system.

Preparation and Evaluation of Extemporaneously Compounded Aspirin Capsules from Crushed Aspirin Tablets

Aims: Extemporaneous preparations of medications might bring about technical and clinical consequences due to formulation failures. Therefore, all such prepared formulas should undergo valid and reliable procedures supported by solid data. Otherwise, patients can experience significant risk due to microbial contamination or physical or chemical changes during the preparation process. Thus, effective extemporaneous preparation relies on correct calculations to avoid extra and serious harm. Therefore, because 50-mg aspirin capsules are not available in Saudi Arabia, this study aimed to formulate 50-mg capsules from available 100-mg aspirin tablets.
 Methodology: Quality control tests of the preparations were carried out at the time of preparation and after one month of storage at 25 °C and at 40 °C and 75% relative humidity. All tests were carried out according to the British and United States pharmacopeia monograph of aspirin.
 Results: The drug content assay and uniformity test indicated that the aspirin capsules were within the pharmacopeial limits. The disintegration time for all aspirin capsules was within the pharmacopeial limits of 30 minutes. The aspirin release profile showed that approximately 90% of the aspirin dissolved after 10 minutes.
 Conclusion: The results indicated that the extemporaneous preparation of ASA capsules complied with the quality control tests for freshly prepared capsules and after one month of storage at room temperature and at 40 °C and 75% relative humidity. The dissolution profile of these capsules indicates immediate and high release of ASA, which is essential to ensure the required absorption. This study is of great importance for patients who need to take this dose of ASA. Pharmacists can prepare good-quality capsules with the desired ASA content using a 100-mg ASA tablet as a source of the active ingredient.

Development of stability indicating method for quality assessment of African Albendazole tablets

In order to assess the quality of Albendazole tablets (Alb) sampled in three countries from West Africa, several physical and chemical tests were performed on tablets at normal conditions. A simple and economic HPLC method has been developed, validated and used for the simultaneous determination of Albendazole (Alb) content, as well as its impurities and the uniformity of its content. The stability-indicating HPLC method was performed on a Symmetry C18-5µm 250 mm × 4.6 mm column with a gradient elution using a mobile phase composed of acetonitrile and sodium acetate buffer. The flow rate was set at 1 mL.min−1 and the eluent was monitored at 295nm. The method was validated for specificity, linearity, accuracy, precision, robustness and detection and quantification limits, in accordance with International Conference on Harmonisation Quality 2 (ICH Q2) guidelines. This method was performed on different Alb samples (originals and generics) products collected from Senegal, Niger and Mali. The obtained results showed that, the contents of the generic tablets from Niger and Mali comply with the United States Pharmacopeia (USP) monograph acceptance criteria. However, more than 20% of the generic tablets don’t meet the USP monograph impurity limits. In conclusion, the described analytical method is simple, sensitive and accurate. Thus, it could be useful for manufacturing and quality control assays.

Assessment of Purity Parameters of Generic and Brand Name Losartan Potassium

Background: Generic products must be bioequivalent to the innovator brand product. Nevertheless, in addition to meeting bioequivalence standards, attention must be paid to the content of the active substance and contaminants in generic drugs. Objective: This study compared the pharmaceutical quality of four generic losartan potassium formulations with the brand-name product: Cozaar®. Methods: The United States Pharmacopeia (USP) losartan potassium standard was used as reference material. The products tested (all 50 mg formulations) included four generic tablet formulations and the innovator brand product Cozaar®. Active substance content, organic impurities, and elemental impurities were assessed following the USP monograph for losartan potassium tablets and USP Chapter <233> on Elemental Impurities. Results: The results showed that three of the four generic products had low content of the active ingredient. The values ranged from 86.4 to 93.8%, being acceptable not below 95% of the labeled amount. Organic impurities were not detected in any of the products, and of the 13 elemental impurities tested, only four elements were detected. The elemental impurities Cr, Ni, Cu, and As were, however, in amounts within the limits established by the USP monograph. The only concern on the generic drugs analyzed was the low content of the active ingredient in 75% of the products. Conclusion: Since losartan is a drug of continuous use, lower content of the active ingredient may go unnoticed by the users of the generic product and entailed clinical consequences during long-term therapy.

Development of a Unified Reversed-Phase HPLC Method for Efficient Determination of EP and USP Process-Related Impurities in Celecoxib Using Analytical Quality by Design Principles.

This article presents the development of a reversed-phase (RP) high-performance liquid chromatographic (HPLC) method for determination of process-related impurities in a celecoxib drug substance following Analytical Quality by Design (AQbD) principles. The method from European Pharmacopeia (EP) for celecoxib drug substance does not sufficiently separate celecoxib from its EP impurity B because the system suitability criterion is not achieved (resolution NLT 1.8). The same issue was observed with the proposed method from United States Pharmacopeia (USP) for celecoxib capsules, where EP impurity A elutes under the main peak. A new HPLC method was developed that eliminates the disadvantages of the two pharmacopeial methods and is capable of efficiently separating and determining all seven impurities listed in EP and the proposed USP monographs. The development of a new HPLC method started with method scouting, in which various C18 and phenyl stationary phases were tested. Improved selectivity was obtained only with a chiral stationary phase. An immobilized Chiralpak IA-3 column used in RP mode turned out to be the most appropriate for method optimization. The ratio of acetonitrile in the mobile phase, flow rate, and column temperature were recognized as critical method parameters (CMPs) and were further investigated using a central composite face response-surface design. A multiple linear regression (MLR) method was applied to fit the mathematical models on the experimental data to determine factor–response relationships. The models created show adequate fit and good prediction abilities. The Monte Carlo simulation method was used to establish the design space. The method developed was verified in terms of precision, sensitivity, accuracy, and linearity, and the results showed that the new method is suitable for determination of seven process-related impurities of celecoxib.

Accessibility and potency of uterotonic drugs purchased by simulated clients in four districts in India.

BackgroundSurveillance of drug quality for antibiotics, antiretrovirals, antimalarials and vaccines is better established than surveillance for maternal health drugs in low-income countries, particularly uterotonic drugs for the prevention and treatment of postpartum hemorrhage. The objectives of this study are to: assess private sector accessibility of four drugs used for uterotonic purposes (oxytocin, methylergometrine, misoprostol, valethamate bromide); and to assess potency of oxytocin and methylergometrine ampoules purchased by simulated clients.MethodsThe study was conducted in Hassan and Bagalkot districts in Karnataka state and Agra and Gorakhpur districts in Uttar Pradesh state. A sample of 877 private pharmacies was selected (using a stratified, systematic sampling with random start), among which 847 were successfully visited. The target sample size for assessment of accessibility was 50 pharmacies per drug, per district. The target sample size for potency assessment was 100 purchases each of oxytocin and methylergometrine across all districts. Successful drug purchases varied by state.ResultsIn Agra and Gorakhpur, 90%-100% of visits for each of the drugs resulted in a purchase. In Bagalkot and Hassan, only 29%-52% of visits for each drug resulted in a purchase. Regarding potency, the percent of active pharmaceutical ingredient was assessed using United States Pharmacopeia monograph #33 for both drugs; 193 and 188 ampoules of oxytocin and methylergometrine, respectively, were assessed. The percent of oxytocin ampoules outside manufacturer specification ranged from 33%-40% in Karnataka and from 22%-50% in Uttar Pradesh. In Bagalkot and Hassan, 96% and 100% of the methylergometrine ampoules were outside manufacturer specification, respectively. In Agra and Gorakhpur, 54% and 44% were outside manufacturer specification, respectively.ConclusionPrivate sector accessibility of uterotonic drugs in study districts in Karnataka warrants attention. Most importantly, interventions to assure quality oxytocin and particularly methylergometrine are needed in study districts in both states.

Accessibility and potency of uterotonic drugs purchased by simulated clients in four districts in India

Surveillance of drug quality for antibiotics, antiretrovirals, antimalarials and vaccines is better established than surveillance for maternal health drugs in low-income countries, particularly uterotonic drugs for the prevention and treatment of postpartum hemorrhage. The objectives of this study are to: assess private sector accessibility of four drugs used for uterotonic purposes (oxytocin, methylergometrine, misoprostol, valethamate bromide); and to assess potency of oxytocin and methylergometrine ampoules purchased by simulated clients. The study was conducted in Hassan and Bagalkot districts in Karnataka state and Agra and Gorakhpur districts in Uttar Pradesh state. A sample of 877 private pharmacies was selected (using a stratified, systematic sampling with random start), among which 847 were successfully visited. The target sample size for assessment of accessibility was 50 pharmacies per drug, per district. The target sample size for potency assessment was 100 purchases each of oxytocin and methylergometrine across all districts. Successful drug purchases varied by state. In Agra and Gorakhpur, 90%-100% of visits for each of the drugs resulted in a purchase. In Bagalkot and Hassan, only 29%-52% of visits for each drug resulted in a purchase. Regarding potency, the percent of active pharmaceutical ingredient was assessed using United States Pharmacopeia monograph #33 for both drugs; 193 and 188 ampoules of oxytocin and methylergometrine, respectively, were assessed. The percent of oxytocin ampoules outside manufacturer specification ranged from 33%-40% in Karnataka and from 22%-50% in Uttar Pradesh. In Bagalkot and Hassan, 96% and 100% of the methylergometrine ampoules were outside manufacturer specification, respectively. In Agra and Gorakhpur, 54% and 44% were outside manufacturer specification, respectively. Private sector accessibility of uterotonic drugs in study districts in Karnataka warrants attention. Most importantly, interventions to assure quality oxytocin and particularly methylergometrine are needed in study districts in both states.

Characterization of currently marketed heparin products: Key tests for LMWH quality assurance

During the 2007–2008 heparin crisis it was found that the United States Pharmacopeia (USP) testing monograph for heparin sodium or low molecular weight heparins did not detect the presence of the contaminant, oversulfated chondroitin sulfate (OSCS). In response to this concern, new tests and specifications were developed by the Food and Drug Administration (FDA) and USP and put in place to detect not only the contaminant OSCS, but also to improve assurance of quality and purity of these drug products. The USP monographs for the low molecular weight heparins (LMWHs) approved for use in the United States (dalteparin, tinzaparin and enoxaparin) are also undergoing revision to include many of the same tests used for heparin sodium, including; one-dimensional (1D) 500MHz 1H NMR, SAX-HPLC, percent galactosamine in total hexosamine and anticoagulation time assays with purified Factor IIa or Factor Xa. These tests represent orthogonal approaches for heparin identification, measurement of bioactivity and for detection of process impurities or contaminants in these drug products. Here we describe results from a survey of multiple lots from three types of LMWHs in the US market which were collected after the 2009 heparin sodium monograph revision. In addition, innovator and generic versions of formulated enoxaparin products purchased in 2011 are compared using these tests and found to be highly similar within the discriminating power of the assays applied.

Diligence needed during transition in heparin products’ labels

Labels on newly manufactured heparin products will prominently state the number of units of drug in the entire container once revisions to the United States Pharmacopeia monographs for heparin lock flush solution and heparin sodium injection go into effect on May 1. This change, although intended

A dose–response study in animals to evaluate the anticoagulant effect of the stage 2 unfractionated heparin USP monograph change

The United States Pharmacopeia (USP) monograph for unfractionated heparin (UFH) was revised in October 2009. This revision was anticipated, based upon in vitro tests, to reduce UFH potency by approximately 10%. To study the potential in vivo consequences of the monograph change, we evaluated activated partial thromboplastin time (aPTT) and activated clotting time (ACT) responses in animals. Female mini-pigs and monkeys (n=8/species) were administered intravenously 60, 54, 48, or 42U/kg and 50, 45, 40, or 35U/kg “old” (pre-USP revision) UFH, respectively, in a Williams 4×4 crossover design. Blood samples for aPTT and ACT were collected at 15min after dosing. The same study design was then repeated using “new” (post-USP revision) UFH. Mean “new” UFH aPTT and ACT values were generally lower than those for “old” UFH although individual animal responses varied considerably. The aPTT and ACT response was generally dose-proportional for both “old” and “new” UFH. These studies indicate that the USP monograph alteration for UFH may result in a modest reduction in the anticoagulant response across a population, but the variability in animal responses underscores the importance of individualization of clinical UFH dosing and the importance of anticoagulant test monitoring.

Characterization of currently marketed heparin products: key tests for quality assurance

During the 2007-2008 heparin crisis, it was found that the United States Pharmacopeia (USP) testing monograph for unfractionated heparin sodium (UFH) did not detect the presence of the contaminant, oversulfated chondroitin sulfate (OSCS) in heparin. In response to this concern, new tests and specifications were developed by the Food and Drug Administration (FDA) and USP and put in place to not only detect the contaminant OSCS but also to improve assurance of quality and purity of the drug product. Additional tests were also developed to monitor the heparin supply chain for other possible economically motivated additives or impurities. In 2009, a new USP monograph was put in place that includes 500MHz (1)H NMR, SAX-HPLC, %galactosamine in total hexosamine, and anticoagulation time assays with purified factor IIa or factor Xa. These tests represent orthogonal approaches for UFH identification, measurement of bioactivity, and for detection of process impurities or contaminants in UFH. The FDA has applied these analytical approaches to the study of UFH active pharmaceutical ingredients in the marketplace. Here, we describe results from a comprehensive survey of UFH collected from seven different sources after the 2009 monograph revision and compare these data with results obtained on other heparin samples collected during the 2007-2008 crisis.

Chromatographic Fingerprint Analysis of Pycnogenol® Dietary Supplements

The bark of maritime pine (Pinus pinaster Aiton) has been widely used as a remedy for various degenerative diseases. A standard high-performance liquid chromatographic (HPLC) procedure for Pycnogenol analysis is a method specified in the United States Pharmacopeia (USP) monograph, which requires measurement of peak areas and identification of four components of the extract: caffeic acid, catechin, ferulic acid, and taxifolin. In this study, a fingerprint analysis using an HPLC method based on the USP monograph has been developed to provide additional qualitative information for the analysis of Pycnogenol-containing dietary supplements (PDS). Twelve commercially available PDS samples were purchased and analyzed along with a standard Pycnogenol extract. Their chromatographic fingerprints were analyzed using principal component analysis. The results showed that two of the samples were not consistent with the standard reference Pycnogenol extract. One contained other active ingredients in addition to Pycnogenol, and the other may have resulted from a quality control issue in manufacturing.

Drug incompatibility chemistry

The chemical interactions that cause drug incompatibility in solutions, with emphasis on the acid-base and ionized-nonionized forms of organic, weak, electrolyte drugs, are examined. When the dilution or mixing of the salt or ionized forms of organic drugs results in precipitation, the most likely cause is formation of the nonionized drug forms. More than 90% of drugs are organic, weak electrolytes, especially those compounded, manufactured, or reconstituted as injections in predominantly ionized or salt forms. Acid-base reactions are the most common causes of drug incompatibility as precipitation of nonionized drug forms. Precipitation is likely when oppositely charged, organic drug ions that contain aromatic rings are combined in relatively strong concentrations. Salts of polyvalent anions and cations are generally less soluble than salts in which both ions are monovalent or in which one ion is monovalent and its opposite ion is polyvalent. The most clinically important potential precipitates among these ions are dibasic and monohydrogen calcium phosphate. Incompatibility of drug and nutrient injections is clinically hazardous. Knowledge of products' chemical facts, organic acid-base equilibria in relation to ionization and nonionization and aqueous solubility, and ranges of pH and ingredient strength from United States Pharmacopeia monographs and product labeling is the foundation of expertise in drug incompatibility. Precipitation in injectable drug solutions should be suspected, particularly when oppositely charged drug salts are mixed in relatively strong concentrations and when pH values of dilutions create more than 1% of nonionized drug forms.

Column selection for pharmaceutical analyses based on a column classification using four test parameters

This paper focuses on the usability of a previously developed column classification system, applied to pharmaceutical analyses. The separation of two drugs from their respective related substances was investigated on 65 new reversed-phase liquid chromatographic columns. The chromatographic procedure for fluoxetine hydrochloride was performed according to the method prescribed in the European Pharmacopoeia monograph while the separation of gemcitabine hydrochloride was carried out according to the United States Pharmacopeia monograph. It was shown that the column ranking system is a helpful tool in the selection of a suitable column.

Influence of Higher Rates of Agitation on Release Patterns of Immediate‐Release Drug Products

AbstractThe dissolution procedure serves as a quality control test to assure batch‐to‐batch uniformity and bioequivalence of a product once the bioavailability of the product has been established. It can also be used to detect manufacturing and/or process variations that could reduce product bioavailability. Dissolution testing must be conducted at an appropriate agitation rate. Tests conducted at high agitation rates may lose the ability to differentiate between good and bad products. Although the effect of high agitation rates has been known for some time, several immediate‐release drug products still have United States Pharmacopeia (USP) monograph dissolution procedures that require very high agitation rates. A systematic survey was conducted on marketed tablets of chloroquine phosphate, griseofulvin, hydroxychloroquine sulfate, isocar‐boxazide, primaquine phosphate, and sulfadiazine. Each of these products has a USP monograph requiring a dissolution test at a paddle speed of 100rpm. To study the influence of agitation rate on the dissolution rate of these products, dissolution studies were conducted at paddle speeds of 50, 75, and 100rpm with the USP apparatus 2 (paddle method). The dissolution rate increased with an increase in the agitation rate from 50 to 75rpm. However, no significant increase in the dissolution rate was noted with an increase in the agitation rate from 75 to 100rpm. The data support the position that the higher agitation rate of 100rpm is not necessary for a quality control procedure or a compendial standard for the products tested.

Rational Limits for Drug Impurities

The United States Pharmacopeia (USP) has developed policies on drug substance purity and organic volatile impurities. This paper will include the historical background and the scientific basis of these policies and will give several examples of how they are reflected in the tests that are included in USP monographs. Data on the types of analytical methods used in assessing the purity of compendial articles will also be presented.