Quality Control

• Definition The term quality control refers to the sum of all procedures undertaken to ensure the identity and purity of a particular pharmaceutical product. Such procedures may range from the performance of simple chemical experiments which determine the identity and screening for the presence of particular pharmaceutical substance to more complicated requirements of pharmacopoeial monographs
• The quality of a product may deviate from the standard required so carrying out analysis is important in order to determine the quality. Testing a pharmaceutical product involves chemical, physical, and some time microbiological evaluation or test. Counterfeit medicines; The WHO defines a counterfeit drug as a product that is with intent and illegally mislabelled with respect to its identity and/or source. Counterfeiting of medicinal products, active pharmaceutical ingredients or product labels are criminal offences, which may endanger patient health.
• Counterfeit products that contain no active ingredient and those that contain the wrong active ingredient or the correct active ingredient in the wrong amount can be detected by carrying out appropriate identification and quantitative tests. In situations where resources for accurate and precise quantitative testing are limited, for example in underdeveloped countries, basic tests, including semi–quantitative tests, may be sufficient to detect these types of counterfeit medicines. ► It may also be possible to identify products as being counterfeit by their general appearance (color, markings, etc.); particularly when the appearance differs from a genuine batch of the product.
• For this reason, laboratories that regularly undertake checks for counterfeit medicines maintain a stock of genuine reference products for comparison. Examination of the labelling should also be carried out to check the accuracy of the information presented. Labels of products made by counterfeit manufacturers may contain errors that are evident to an expert. ► The quality of the packaging materials and of the printing should also be inspected carefully and, if possible, compared to that of a genuine batch of the product.
  Analytical process ► It has been estimated that £ 10 billion is spent each year on analysis in the UK alone and such analytical processes can be found in various industries as those producing food, beverages, cosmetics, detergents, metals, paints, water, agrochemical, biotechnology products and pharmaceutical products. With such large amount of money being spent on analytical quality control, great spent must be placed on providing accurate and precise analysis
• Differentiation of analytical process ► Analytical process may be categorized into five groups based on the objective; ► Standard methods: This may be national standard procedures, or international guidelines ( e.g. American society for testing and material (ASTM), international organization for standardization (ISO), international union of pure and applied chemistry (IUPAC), etc.) and standards, or procedures described by legal regulations, ► Comparable laboratory procedures: quantitative analytical processes which vary in procedure from standard methods, but are verified as equivalence to using standard methods.
• Other quantitative analytical procedures which have various uses and objectives in the laboratory out side of governmentally regulated areas. These also include the latest analytical procedures for which standards have not yet been established ► Field methods: analytical processes which can be performed out side the laboratory. With the aid of objective measurement methods, field methods can bring quantitative or semi-quantitative results depending on previous handling of the sample and quality assurance procedures
  Quality of analytical process ► The appropriate analytical process for obtaining the answer to a specific question must not always be the scientifically “best” procedure. However, it is important that the results of an analysis, obtained through adherence to legal regulations, should if necessary be defensible in court, or in other word legally binding.
  Precision requirements of analytical procedures as related to analytical problem Question Is a substance present or not Quality required for analytical process Yes/no decision; a sufficiently sensitive orientation test is applicable. In which range of concentration is the substance present An orientation test indicating a corresponding gradation of concentration regions is applicabl Dose the concentration lie far below a verifiable threshold limit? A highly precise analytical results is not necessary; orientation test and field methods are applicable Has the threshold limit been exceeded? A highly accurate (meaning both precision and trueness) analytical result is required, i.e. only reference procedure and if available comparable laboratory procedures are applicable. In what concentration, ± confidence interval, is the substance in question present in the sample? A highly accurate (meaning both precision and trueness) analytical result is required. If the analytical result is legally binding, only standard methods or comparable laboratory procedures are an acceptable. Otherwise, other analytical procedures whose reliability has been proven are applicable.
  The objective of analytical work is the achievement of reliable analytical results of a defined quality. Quality characteristics of analytical process are therefore: Specificity; the ability of analytical process to register only the desired analyte, while other components or characteristics present in the sample (known as the matrix) do not influence the results. Sensitivity: the change in measured value per change in analyte. Accuracy: is the sense of both trueness (lack of systematic errors) and precision (measurement of differences between results, as obtained by repeated use of an established analytical process on the same sample). Imprecision is caused by random errors.
• Four phase modules of analytical quality assurances ► The chronology of quality assurance characteristics is reflected in a 4-phase model of analytical quality assurance using statistical method, as described below: ► Phase 1: the quality characteristics of a new analytical process in need of calibration are determined and if necessary the process is improved and documented. ► Phase 11: preparative quality control. An analytical process whose quality characteristics have already been documented is made operational for routine analysis. This includes achieving and maintaining sufficient analytical quality test before routine analysis begins.
  Phase 111: performance of all internal laboratory quality assurance measures of routine analysis, accompanied by ► Phase 1V: external laboratory quality assurance in the form of inter laboratory tests and external audits.
• Quality Assurance of pharmaceutical products It is important in many spheres to have reliable, ► interchangeable data on the recovery, identification and quantification of drugs. In the pharmaceutical industry, quality control and assessment (QC and QA) are required to monitor production and assess the quality, safety and efficacy of its products. In clinical analysis, QC and QA is vital to the quality and safety of patient care, to the diagnosis and control of therapy for the individual patient, and for research and public health purposes.
  For toxicologists and pathologists, QC and QA help to distinguish between therapeutic and overdose levels and to determine the cause of death. In law enforcement, it is used to provide information to link drugs offences, to identify drugs distribution networks and to provide evidence of possession or misuse for the courts. It is also essential for monitoring individuals on drug rehabilitation programmers
• Medicinal products should be safe and efficacious. Manufacturers of medicinal products are required by law to possess marketing authorizations from government regulatory agencies in countries in which their products are marketed and to manufacture their products in compliance with Good Pharmaceutical Manufacturing Practice (GMP) standards. These requirements involve conducting appropriate quality control tests to check that the product conforms to a specification that assures its safety and efficacy. ► Typical specifications include tests to verify the chemical composition and physical properties of the medicine and to ensure that the medicine is not contaminated by micro–organisms or other substances.
  Although medicinal products are subject to quality–control testing by the manufacturer, they may also have to be checked independently to: 1. determine or confirm their composition 2. assess their suitability for use 3. investigate defects 4. identify unknown medicinal products 5. identify contaminants 6. determine if the products have been adulterated 7. establish if the products are counterfeit.
• In most cases that involve checking of the quality of a medicinal product, it is preferable to use the test methods in the product specification defined in the manufacturer’s marketing authorization for the product. This is because the product specifications, including the test methods and acceptance criteria, have been assessed by the government regulatory agency as being valid and justified. Some manufacturers publish their analytical methods in the scientific literature. Consequently, it may be worthwhile to check the literature or maintain a library of published methods.
• Alternatively, in certain circumstances, manufacturers may provide the independent laboratory with the test methods, acceptance criteria and reference materials. ► If the laboratory does not have access to the authorized finished product specification, including the test methods and acceptance criteria, pharmacopoeial monographs can be used, where applicable ► In the absence of a pharmacopoeial monograph, alternative approaches are required to obtain as much information as possible about the quality of the medicinal product
• This requires the development of valid test methods to measure relevant quality parameters and the application of generally accepted criteria to assess the quality. However, if the laboratory uses different analytical techniques to those used by the manufacturer [e.g. a high performance liquid chromatographic (HPLC) technique instead of an ultraviolet (UV) spectrophotometric technique], the results may differ significantly from those obtained by the manufacturer, particularly if high levels of impurities are present
  Pharmacopoeial specification and methods ► Pharmacopoeias are good sources of the specifications and standards with which a wide range of commonly used drug substances, excipient, packaging materials and finished products must comply throughout their shelf–life. The principal pharmacopoeias are the European Pharmacopoeia , British Pharmacopoeia ► National pharmacopoeias of some countries, for example Japan, China and individual European countries, may provide specifications for pharmaceuticals that are available only in those countries. The International Pharmacopoeia published by the World Health Organization is intended for use by WHO member states who wish to establish pharmacopoeial requirements for pharmaceuticals used in their country