Reliability‐targeted HPLC–UV method validation—A protocol enrichment perspective

Method validation is important in analytical chemistry to obtain the reliability of an analytical method. Guidelines provided by the regulatory bodies can be used as a general framework to assess the validity of a method. Since these guidelines do not focus on the reliability of analytical results exclusively, this study was aimed to combine a few recently evolved strategies that may render analytical method validation more reliable and trustworthy. In this research, the analytical error function was determined by appropriate polynomial regression statistics that determine the range of analyte concentration that may lead to more accurate measurements by producing the least possible total error in the assay and can be regarded as a reliable weighting method. The reliability of the analytical results over a particular concentration range has been proposed by a Bayesian probability study. In order to ensure the applicability of this approach, it was applied for the validation of an HPLC–UV assay method dedicated to the quantification of cefepime and tazobactam in human plasma. A comparison between the newer approach and the usual method validation revealed that the application of analytical error function and Bayesian analysis at the end of the validation process can produce significant improvements in the analytical results.     

Validation requirements for chemical methods in quantitative analysis – horses for courses?

 Although the validation process necessary to ensure that an analytical method is fit for purpose is universal, the emphasis placed on different aspects of that process will vary according to the end use for which the analytical procedure is designed. It therefore becomes difficult to produce a standard method validation protocol which will be totally applicable to all analytical methods. It is probable that far more than 30% of the methods in routine laboratory use have not been validated to an appropriate level to suit the problem at hand. This situation needs to change and a practical assessment of the degree to which a method requires to be validated is the first step to a reliable and cost effective analytical industry. Received: 22 September 1997 · Accepted: 28 November 1997     

Intra-laboratory assessment of method accuracy (trueness and precision) by using validation standards

Assessment of accuracy of analytical methods is a fundamental stage in method validation. The use of validation standards enables the assessment of both trueness and precision of analytical methods at the same time. Procedures of intra-laboratory testing of method accuracy using validation standards are outlined and discussed.     

Immunoaffinity extraction in veterinary residue analysis--a regulatory viewpoint.

The utility of immunoaffinity chromatography (IAC) for the purification of veterinary drug residues from extracts of foods of animal origin is widely acknowledged. However owing to the unique nature of the specific antibody reagent used when synthesising an immunosorbent, certain reassurances are needed before an IAC process can be considered an acceptable stage in a routine analytical method. European Community legislation requires applicants for Maximum Residue Limits or national Marketing Authorization for veterinary medicinal products, used in food producing animals, to provide a routine analytical method in accordance with Volume VI of the Rules Governing Medicinal Products in the European Community. In order to ensure the continued supply of immunosorbent material, applicants wishing to use IAC sample clean-up procedures should consider generating the following data: a standard operating procedure (SOP) for antibody production (or cell-line maintenance in the case of monoclonal antibodies), a specifications document of antibody characterisation, an SOP for immunosorbent synthesis, validation of immunosorbent operating conditions and an assessment of its performance criteria. This paper aims to introduce analysts to the technique of IAC and to suggest how those areas of concern highlighted above may be addressed.     

Validation of analytical methods involved in dissolution assays: Acceptance limits and decision methodologies

Dissolution tests are key elements to ensure continuing product quality and performance. The ultimate goal of these tests is to assure consistent product quality within a defined set of specification criteria. Validation of an analytical method aimed at assessing the dissolution profile of products or at verifying pharmacopoeias compliance should demonstrate that this analytical method is able to correctly declare two dissolution profiles as similar or drug products as compliant with respect to their specifications. It is essential to ensure that these analytical methods are fit for their purpose. Method validation is aimed at providing this guarantee. However, even in the ICHQ2 guideline there is no information explaining how to decide whether the method under validation is valid for its final purpose or not. Are the entire validation criterion needed to ensure that a Quality Control (QC) analytical method for dissolution test is valid? What acceptance limits should be set on these criteria? How to decide about method's validity? These are the questions that this work aims at answering. Focus is made to comply with the current implementation of the Quality by Design (QbD) principles in the pharmaceutical industry in order to allow to correctly defining the Analytical Target Profile (ATP) of analytical methods involved in dissolution tests. Analytical method validation is then the natural demonstration that the developed methods are fit for their intended purpose and is not any more the inconsiderate checklist validation approach still generally performed to complete the filing required to obtain product marketing authorization.     

White analytical chemistry-driven stability-indicating concomitant chromatographic estimation of thiocolchicoside and aceclofenac using response surface analysis and red,green, and blue model

White analytical chemistry is a novel concept for the assessment of analytical methods on basis of its validation efficiency, greenness power, and economical efficiency. White analytical chemistry-driven stability indicating chromatographic method has been developed for the concomitant analysis of thiocolchicoside and aceclofenac. The proposed chromatographic method has been developed using a safe and environmental-friendly organic solvents for the concomitant stability study of thiocolchicoside and aceclofenac. The analytical risk assessment was carried out for the identification of high-risk analytical risk factors and analytical method performance attributes. The mixture design was applied for the design of experiments-based response surface modeling of high-risk analytical risk factors and analytical method performance attributes. The degradation products were isolated and characterized using infrared, nuclear magnetic resonance, and mass spectral data. The proposed method was compared for its validation efficiency, greenness power, and cost-efficiency with published chromatographic methods using the red, green, and blue models. The white score of the proposed and reported method was calculated by averaging the red, green, and blue scores of the methods. The proposed method was found to be robust, green, and economical for the concomitant stability study of thiocolchicoside and aceclofenac.     

Automation and validation of HPLC-systems

Summary The automation of chromatographic systems is of increasing interest to industry and research laboratories in routine applications. Besides potentially saving time or making better use of available instrumentation, automation also improves the quality of results by producing more precise and more reproducible HPLC data. The need for the validation of methods and qualification of instruments is increasingly recognised in order to ensure compliance with legal requirements (e.g. in the pharmaceutical industry) and to ensure the reliability of analytical results. Possibilities and requirements for automated HPLC systems are elaborated. Emphasis is placed on defining the goals of validation and on discussing different aspects of the validation of LC methods, system suitability tests, ruggedness of methods and the transfer of LC methods from laboratory to laboratory. Adequate strategies of HPLC method development provide very useful information on the validation and ruggedness of LC methods.     

Recent Trends in Validation of Bioanalytical Methods

Abstract

The assessment of the quality levels of pharmaceutical formulations is done through various validation parameters. Validation of these analytical test procedures is the process by which it is established that the test methods meet the requirements for the intended analytical application. The validation criterion also applies to bioanalytical methods used for non‐human pharmacology/toxicology studies and preclinical studies. Bioanalytical method validation includes all the procedures, which demonstrate that a particular method used for quantitative measurement of analytes in a given biological matrix, such as blood, plasma, serum, or urine, is reliable and reproducible for the intended use.     

Equipment qualification and its application to conductivity measuring systems

It is only possible to obtain analytical results that are suitable for their intended purpose if the equipment used is capable of producing measurements of the required quality. To ensure that this requirement is met, analysts should define the performance criteria required from the instruments, ensure that only suitable instruments are selected for analytical measurements, and confirm that these instruments continue to meet these criteria for their entire operational life. This process should be conducted on a formal, documented basis, known as equipment qualification. In addition to describing the key elements of equipment qualification for all analytical instruments, this paper gives specific guidance on its application to conductivity systems that has never previously appeared in the literature. The benefits of performing equipment qualification are highlighted and guidance is given on the selection of control standards and why the equipment vendor performing stages of equipment qualification can be of benefit to the user. The relationship between equipment qualification and method validation is discussed, including how these activities play a major role in determining the quality control measures that should be applied to routine analysis.     

Method ruggedness studies incorporating a risk based approach: a tutorial

This tutorial explains how well thought-out application of design and analysis methodology, combined with risk assessment, leads to improved assessment of method ruggedness. The authors define analytical method ruggedness as an experimental evaluation of noise factors such as analyst, instrument or stationary phase batch. Ruggedness testing is usually performed upon transfer of a method to another laboratory, however, it can also be employed during method development when an assessment of the method's inherent variability is required. The use of a ruggedness study provides a more rigorous method for assessing method precision than a simple comparative intermediate precision study which is typically performed as part of method validation. Prior to designing a ruggedness study, factors that are likely to have a significant effect on the performance of the method should be identified (via a risk assessment) and controlled where appropriate. Noise factors that are not controlled are considered for inclusion in the study. The purpose of the study should be to challenge the method and identify whether any noise factors significantly affect the method's precision. The results from the study are firstly used to identify any special cause variability due to specific attributable circumstances. Secondly, common cause variability is apportioned to determine which factors are responsible for most of the variability. The total common cause variability can then be used to assess whether the method's precision requirements are achievable. The approach used to design and analyse method ruggedness studies will be covered in this tutorial using a real example.     

化学分析方法验证和确认的应用研究

分析方法的验证/确认是实验室引进新方法时必做的工作,也是实验室技术工作的重点和难点之一。对实验室采用分析方法的验证和确认工作进行归纳总结,详述了分析方法选择性、测量范围、线性范围、检出限和定量限、精密度、准确度的验证/确认方法及结果判定方式。适用于实验室引进的标准方法(包括标准变更)和非标准方法(实验室设计/制定的方法、超出预定范围使用的标准方法、扩充和修改过的标准方法)的验证和确认。     

Analytical Method Performance Evaluation (AMPE)--a software tool for analytical method validation

A Windows-based software tool [Analytical Method Performance Evaluation (AMPE)] was developed to support the validation of analytical methods. The software implements standard statistical approaches commonly adopted in validation studies to estimate analytical method performance (limits of detection and quantitation, accuracy, specificity, working range, and linearity of responses) according to ISO 5725. In addition, AMPE proposes the application of innovative and unique approaches for the assessment of analytical method performance. Specifically, AMPE proposes the use of difference-based indexes to quantify the agreement between measurements and reference values, the use of pattern indexes to quantify methods bias with respect to specific external variables, and the application of fuzzy logic to aggregate into synthetic indicators the information collected independently via the different performance statistics traditionally estimated in validation studies. Aggregated measures are particularly useful for methods comparison, when more than one method is available for a specific analysis and it may be of interest to identify the best performing one taking into account, simultaneously, the information available from different performance statistics. Illustrative examples of the type of outputs expected from AMPE-based validation sessions are given. The extensive data handling capabilities and the wide range of statistics supplied in the software package makes AMPE suitable for specific needs that may arise in different validation studies. The installation package, complete with a fully documented help file, is distributed free of charge to interested users along with input files exemplary of the type of entry data required to run validation data analyses.     

Human being as a part of measuring system influencing measurement results

The role of human being as a part of a measuring system in a chemical analytical laboratory is discussed. It is argued that a measuring system in chemical analysis includes not only measuring instruments and other devices, reagents and supplies, but also a sampling inspector and/or analyst performing a number of important operations. Without this human contribution, a measurement cannot be carried out. Human errors, therefore, influence the measurement result, i.e., the measurand estimate and the associated uncertainty. Consequently, chemical analytical and metrological communities should devote more attention to the topic of human errors, in particular at the design and development of a chemical analytical/test method and measurement procedure. Also, mapping human errors ought to be included in the program of validation of the measurement procedure (method). Teaching specialists in analytical chemistry and students how to reduce human errors in a chemical analytical laboratory and how to take into account the error residual risk, is important. Human errors and their metrological implications are suggested for consideration in future editions of the relevant documents, such as the International Vocabulary of Metrology (VIM) and the Guide to the Expression of Uncertainty in Measurement (GUM).     

Increasing the reliability of the identification by high-performance liquid chromatography by means of selective and/or sensitive detection

An approach for quantitative assessment of the reliability of identification at high-performance liquid chromatography is proposed. The quantitative assessment of identification is useful for determination of selectivity at validation of the analytical methods. Chromatograms and spectra of the analytes are presented as maps in which characteristics as retention times, detector's signals, maxima and minima and another characteristics of spectra are used for identification. A formula for quantitative determination of the contribution of these characteristics on the reliability of identification is given. Using the more selective diode array detector than the convenient UV detector increases the reliability by several orders. A similar result was obtained when the UV detector was replaced with the more sensitive and selective fluorescence detector. Despite of the small contribution of the separation to the reliability its influence is very important for distinguishing of isomers because their spectra are identical.     

Automated ion-selective measurement of lithium in serum. A practical approach to result-level verification in a two-way method validation

 The Quality Assurance Department of Medix Diacor Labservice evaluated a two-way method validation procedure for serum lithium quantification in therapeutic drug monitoring In the process of a company fusion and rationalization of two considerably large production lines, three independent ion-selective electrode (ISE) methods were surveyed, among many others. While tailoring the new medical laboratory production, subcontracting from a collaborating company was discontinued. Likewise, modernization of the ISE instrumentation was unavoidable to increase throughput and effectiveness. It was important that the new result levels should be comparable both with the former subcontractor's levels and with the levels reported from the previously existing instrumentation. The aim of this study was to evaluate the most crucial performance characteristics of a novel lithium method in comparison to the two ISE test methods being withdrawn. The standardized lithium test method was inspected in terms of linear measurement range, analytical variation, bias, past and on-going proficiency testing, in addition to method comparison, to achieve the desired analytical goals. Fulfilling the accreditation requirements in terms of the introduced method validation parameters is discussed. Received: 19 April 2000 / Accepted: 26 July 2000     

Speciation analysis of chromium in drinking water samples by ion-pair reversed-phase HPLC–ICP-MS: validation of the analytical method and evaluation of the uncertainty budget

The approach presented in this article refers to the modification of a method for the detection and quantitative determination of chromium species in water by high-performance liquid chromatography inductively coupled plasma mass spectrometry. The main aim of this work was to establish a detailed validation of the analytical procedure and an estimation of the budget of measurement uncertainty which was helpful in recognizing the critical points of the presented method. As a result of the method validation experiment, the obtained limit of quantification, repeatability and intermediate precision were satisfied for the quantification Cr(III) and Cr(VI) in water matrices. The trueness of the method was verified via an estimation of the recovery of the spiked real samples. The recovery rate of both determined analytes was found to be between 93 and 115 %. Considering that the validation of the method and the evaluation of measurement uncertainty are crucial for quantitative analysis, the above-mentioned assessment of the uncertainty budget was performed in two different ways: a modelling approach and a single-laboratory validation approach. The measurement uncertainties of the results were found to be 4.4 and 7.8 % for Cr(III), 4.2 and 7.9 % for Cr(VI) using the classical concept and method validation data, respectively. This paper is the first publication to presenting all the steps needed to evaluate the measurement uncertainty for the speciation analysis of chromium species. In summary, the obtained results demonstrate that the method can be applied effectively for its intended use.     

Validation of analytical methods based on accuracy profiles

Validation is a very living field in analytical chemistry as illustrated by the numerous publications addressing this topic. But, there is some ambiguity in this concept and the abundant vocabulary often does not help the analytical chemist. This paper presents a new method based on the fitness-for-purpose approach of the validation. It consists in building a graphical decision-making tool, called the accuracy profile. Using measurements collected under reproducibility or intermediate precision condition, it allows computing an interval where a known proportion of future measurements will be located. When comparing this interval to an acceptability interval defined by the result end-user it is possible to simply decide whether a method is valid or not. The fundamentals of this method are presented starting from an accepted definition of validation. An example of application illustrates how validation can be experimentally organized and conclusion made.     

A validation concept for purity determination and assay in the pharmaceutical industry using measurement uncertainty and statistical process control

 The analytical chemists in process development in the pharmaceutical industry have to solve the difficult problem of producing high quality methods for purity determination and assay within a short time without a clear definition of the substance to be analyzed. Therefore the quality management is very difficult. The ideal situation would be that every method is validated before use. This is not possible because this would delay the development process. A process-type quality development approach with an estimation type fast validation (measurement uncertainty) is therefore suggested. The quality management process consists of the estimation of measurement uncertainty for early project status. Statistical process control (SPC) is started directly after measurement uncertainty estimation and a classical validation for the end of the project. By this approach a process is defined that allows a fast and cost-efficient way of supporting the development process with the appropriate quality at the end of the process and provides the transparency needed in the development process. The procedure presented tries to solve the problem of the parallelism between the two development processes (chemical and analytical development) by speeding up the analytical development process initially. Received: 25 March 1997 · Accepted: 17 May 1997     

Comparison of quantitative methods for analysis of polyphasic pharmaceuticals

Adequate very sensitive quantification methods are needed for the development and are also now required for the monitoring of undesirable solid form(s) as routine tests. The pre-requisite for quantitation are selectivity, sensitivity and most important the purity of standards and their proper storage, what is a challenge for metastable forms. Several analytical techniques are available such as X-ray diffraction, spectroscopy, thermal analysis and microcalorimetry. The different steps of the validation of the analytical methods and problems to be solved are discussed. Examples illustrate the different techniques and compare their possible advantages and limits. The relative standard deviation of measurements should allow for checking the homogenization procedure of mixtures for calibration. The validation should be carried out following ICH guidelines for validation of analytical methods. Comparison of different techniques in adequate concentration range add confidence in the analytical results.