A. Bouklouze

Critical analysis of several analytical method validation strategies in the framework of the fit for purpose concept.

Analytical method validation is a mandatory step at the end of the development in all analytical laboratories. It is a highly regulated step of the life cycle of a quantitative analytical method. However, even if some documents have been published there is a lack of clear guidance for the methodology to follow to adequately decide when a method can be considered as valid. This situation has led to the availability of several methodological approaches and it is therefore the responsibility of the analyst to choose the best one. The classical decision processes encountered during method validation evaluation are compared, namely the descriptive, difference and equivalence approaches. Furthermore a validation approach using accuracy profile computed by means of beta-expectation tolerance interval and total measurement error is also available. In the present paper all of these different validation approaches were applied to the validation of two analytical methods. The evaluation of the producer and consumer risks by Monte Carlo simulations were also made in order to compare the appropriateness of these various approaches. The classical methodologies give rise to inadequate and contradictory conclusions which do not allow them to answer adequately the objective of method validation, i.e. to give enough guarantees that each of the future results that will be generated by the method during routine use will be close enough to the true value. It is found that the validation methodology which gives the most guarantees with regards to the reliability or adequacy of the decision to consider a method as valid is the one based on the use of the accuracy profile.

Methodologies for the transfer of analytical methods: a review.

The transfer of a method from a laboratory to a production site is an important step in the development cycle of new pharmaceutical products. Method transfers are increasingly implemented due to the economical pressure coming from the rationalization of production sites, analytical subcontracting and fusion of pharmaceutical groups. However, no official guidance regarding study design, data analysis, or decision procedures is present neither in FDA documents nor in ICH documents for method transfers. The experiments performed in such a transfer and the methodology used to accept or reject it should be fitted for purpose. In order to provide to analysts a global view of the problematic of analytical method transfer, this paper reviews the documentation available in the scientific literature about the design of transfer studies and the required sample size. Special focus is also made on the statistical methodologies available for decision making with particular emphasis on risk management. Examples of transfer of pharmaceutical, bio-pharmaceutical and biological methods published in the literature are reviewed in order to illustrate the various possibilities among the strategies for methods transfer.

Determination of binary polymorphic mixtures of fluconazole using near infrared spectroscopy and X-ray powder diffraction: A comparative study based on the pre-validation stage results

The aim of the present study was to develop near infrared (NIR) and X-ray powder diffraction methods (XRPD) able to determine pure crystalline form II of fluconazole in a binary polymorphic mixtures containing forms II and III. In order to give a first performance estimation of both methods, these latters were pre-validated using accuracy profiles, a statistical approach based on β-expectation tolerance intervals. Both methods showed a good trueness, precision and accuracy and their β-expectation tolerance intervals were fully included within the acceptance limits. The comparative study was carried out using statistical analysis based on the work of Bland and Altman. A good agreement between the two methods was demonstrated indicating the interchangeability of NIR method with XRPD method.

Usefulness of capability indices in the framework of analytical methods validation

Analytical methods capability evaluation can be a useful methodology to assess the fitness of purpose of these methods for their future routine application. However, care on how to compute the capability indices have to be made. Indeed, the commonly used formulas to compute capability indices such as Cpk, will highly overestimate the true capability of the methods. Especially during methods validation or transfer, there are only few experiments performed and, using in these situations the commonly applied capability indices to declare a method as valid or as transferable to a receiving laboratory will conduct to inadequate decisions. In this work, an improved capability index, namely Cpk-tol and the corresponding estimator of proportion of non-conforming results (π(Cpk-tol)) have been proposed. Through Monte-Carlo simulations, they have been shown to greatly increase the estimation of analytical methods capability in particular in low sample size situations as encountered during methods validation or transfer. Additionally, the usefulness of this capability index has been illustrated through several case studies covering applications commonly encountered in the pharmaceutical industry. Finally a methodology to determine the optimal sample size required to validate analytical methods is also given using the proposed capability metric.

DO PLACEBO BASED VALIDATION STANDARDS MIMIC REAL BATCH PRODUCTS BEHAVIOUR? CASE STUDIES

Analytical methods validation is a mandatory step to evaluate the ability of developed methods to provide accurate results for their routine application. Validation usually involves validation standards or quality control samples that are prepared in placebo or reconstituted matrix made of a mixture of all the ingredients composing the drug product except the active substance or the analyte under investigation. However, one of the main concerns that can be made with this approach is that it may lack an important source of variability that come from the manufacturing process. The question that remains at the end of the validation step is about the transferability of the quantitative performance from validation standards to real authentic drug product samples. In this work, this topic is investigated through three case studies. Three analytical methods were validated using the commonly spiked placebo validation standards at several concentration levels as well as using samples coming from authentic batch samples (tablets and syrups). The results showed that, depending on the type of response function used as calibration curve, there were various degrees of differences in the results accuracy obtained with the two types of samples. Nonetheless the use of spiked placebo validation standards was showed to mimic relatively well the quantitative behaviour of the analytical methods with authentic batch samples. Adding these authentic batch samples into the validation design may help the analyst to select and confirm the most fit for purpose calibration curve and thus increase the accuracy and reliability of the results generated by the method in routine application.

Analytical Validation of Potentiometric Method for Cetirizinium Ion

Abstract Accuracy and reliability of the analytical results are crucial for ensuring quality, safety, and efficacy of pharmaceutical products. However, to ensure these criteria, analytical validation is required. In this matter, many official documents describing the criteria of validation are available. However, these concern mainly chromatography analysis and bio‐analytical methods of pharmaceutical products, but they do not propose any experimental protocol for direct potentiometric methods using ion‐selective electrodes applied in pharmaceutical analysis. In this work, we are proposing a validation strategy based on the normative and regulatory guidelines applied to a potentiometric method with a polymeric membrane selective to cetirizine dihydrochloride. The statistical analysis obtained from raw data is described for all steps of this protocol. Also this validated method was successfully applied to the determination of cetirizine in pharmaceutical preparations using direct potentiometry with a mean relative standard deviation of 0.57% and a mean recovery of 99.63%.

New Polymeric membrane electrode for azithromycin determination

Abstract A new polymeric membrane electrode has been developed for the determination of azithromycin. The electrode was constructed by incorporating the azithromycin‐tetraiodomercurate ion pair complex into a polyvinylchloride matrix plasticized by nitrobenzene. This sensor exhibited good linear response (−29.8 mV/decade) over the concentration range 1.0×10−2–7.0×10−6 M, using a mixed solution as supporting electrolyte containing phosphate buffer (pH=6.5; I=0.1 M) and acetonitrile (3∶1, v/v). The pH did not affect the electrode performances within the pH range 2–8. Interferences from species such as pharmaceutical excipients are negligible. In order to assess the performance and reliability of the analytical results, the proposed potentiometric method using this selective electrode to azithromycin has been validated. The validated method was successfully applied, using direct potentiometry, to the quantitation of azithromycin in pharmaceutical preparation (RSD=0.87%; mean recovery=99.5%) and in dissolution profile studies of tablets.

Quality of chloroquine tablets available in Africa

Abstract Malaria is the biggest killer of African children, yet it is cheaply preventable and curable with insecticides spraying, impregnated bednets and effective drugs. This study aimed to evaluate the quality of Chloroquine (CQ) tablets available in selected African countries. Twenty-six samples of antimalarial CQ tablet of 100, 150 and 250 mg were collected from 12 African countries and evaluated for their quality in the Drugs Quality Control Laboratory of Rabat, Morocco. The identification and dosage of active pharmaceutical ingredients in the tablets, dissolution rate, hardness and the friability of CQ tablets were performed according to the United States Pharmacopeia (USP) and European Pharmacopoeia (Eur.Ph.) recommended methods. The results showed that 7·7% of the sampled CQ tablets available in Burkina Faso were of low quality. Failure in dissolution profile was found in 50% of CQ tablets sampled from Benin, Burkina Faso, Comoros Union, Mali and Senegal. The findings showed poor quality of CQ tablets available in the African market. This problem may affect the efforts to control malaria in Africa. Efficient regulatory systems of drugs quality control should be implemented.

Flexibility and Applicability of β-expectation tolerance interval approach to assess the fitness of purpose of pharmaceutical analytical methods

An innovative versatile strategy using Total Error has been proposed to decide about the methods validity that controls the risk of accepting an unsuitable assay together with the ability to predict the reliability of future results. This strategy is based on the simultaneous combination of systematic (bias) and random (imprecision) error of analytical methods. Using validation standards, both types of error are combined through the use of a prediction interval or β-expectation tolerance interval. Finally, an accuracy profile is built by connecting, on one hand all the upper tolerance limits, and on the other hand all the lower tolerance limits. This profile combined with pre-specified acceptance limits allows the evaluation of the validity of any quantitative analytical method and thus their fitness for their intended purpose. In this work, the approach of accuracy profile was evaluated on several types of analytical methods encountered in the pharmaceutical industrial field and also covering different pharmaceutical matrices. The four studied examples depicted the flexibility and applicability of this approach for different matrices ranging from tablets to syrups, different techniques such as liquid chromatography, or UV spectrophotometry, and for different categories of assays commonly encountered in the pharmaceutical industry i.e. content assays, dissolution assays, and quantitative impurity assays. The accuracy profile approach assesses the fitness of purpose of these methods for their future routine application. It also allows the selection of the most suitable calibration curve, the adequate evaluation of a potential matrix effect and propose efficient solution and the correct definition of the limits of quantification of the studied analytical procedures.

Multivariate statistical process control in product quality review assessment – A case study

According to the Food and Drug Administration and the European Good Manufacturing Practices (GMP) guidelines, Annual Product Review (APR) is a mandatory requirement in GMP. It consists of evaluating a large collection of qualitative or quantitative data in order to verify the consistency of an existing process. According to the Code of Federal Regulation Part 11 (21 CFR 211.180), all finished products should be reviewed annually for the quality standards to determine the need of any change in specification or manufacturing of drug products. Conventional Statistical Process Control (SPC) evaluates the pharmaceutical production process by examining only the effect of a single factor at the time using a Shewharts chart. It neglects to take into account the interaction between the variables. In order to overcome this issue, Multivariate Statistical Process Control (MSPC) can be used. Our case study concerns an APR assessment, where 164 historical batches containing six active ingredients, manufactured in Morocco, were collected during one year. Each batch has been checked by assaying the six active ingredients by High Performance Liquid Chromatography according to European Pharmacopoeia monographs. The data matrix was evaluated both by SPC and MSPC. The SPC indicated that all batches are under control, while the MSPC, based on Principal Component Analysis (PCA), for the data being either autoscaled or robust scaled, showed four and seven batches, respectively, out of the Hotelling T2 95% ellipse. Also, an improvement of the capability of the process is observed without the most extreme batches. The MSPC can be used for monitoring subtle changes in the manufacturing process during an APR assessment.