technical_guide_for_the_elaboration_of_monographs_7th_edition_20151

II.5.7. II.5.8.

II.5.8.1. Thin-layer chromatography (TLC) (2.2.27.) .............................................................................................................. 27 II.5.8.2. Liquid chromatography (LC) (2.2.29.) ...................................................................................................................... 28 II.5.8.3. Gas-liquid chromatography (GC) (2.2.28.) ................................................................................................................ 33 II.5.8.4. Capillary electrophoresis (CE) (2.2.31.) .................................................................................................................... 33

Absorption spectrophotometry (ultraviolet and visible) (2.2.25.) ........................................................... 22 Related substances .................................................................................................................................. 23

II.5.9. Readily carbonisable substances ............................................................................................................ 34 II.5.10. Foreign anions and/or cations ................................................................................................................ 35 II.5.11. Heavy metals – Elemental Impurities ..................................................................................................... 35 II.5.12. Loss on drying (2.2.32.) .......................................................................................................................... 36 II.5.13. Thermogravimetry (2.2.34.) .................................................................................................................... 36 II.5.14. Semi-micro determination of water (2.5.12.) – (volumetric Karl Fischer) .............................................. 37 II.5.15. Micro determination of water (2.5.32.) – (coulometric Karl Fischer) .................................................... 37 II.5.16. Gas chromatographic determination of water ........................................................................................ 37 II.5.17. Determination of water by distillation (2.2.13.) ...................................................................................... 38 II.5.18. Sulfated ash (2.4.14.) .............................................................................................................................. 38 II.5.19. Residue on evaporation .......................................................................................................................... 38 II.5.20. Residual solvents (2.4.24.) ...................................................................................................................... 38 II.5.21. Bacterial endotoxins ............................................................................................................................... 38 II.6. ASSAY ............................................................................................................................................................ 39 II.6.1. Ultraviolet and visible spectrophotometry (2.2.25.) ............................................................................... 40

II.6.1.1. Direct measurement ................................................................................................................................................... 40 II.6.1.2. Measurement after a colour reaction.......................................................................................................................... 40

II.6.2. Volumetric analysis................................................................................................................................. 40 II.6.3. Chromatography ..................................................................................................................................... 41 II.6.4. Determination of nitrogen by sulfuric acid digestion (2.5.9.) ................................................................. 41 II.7. STORAGE ...................................................................................................................................................... 41 II.8. LABELLING .................................................................................................................................................. 42 II.9. IMPURITIES .................................................................................................................................................. 42 II.10. FUNCTIONALITY-RELATED CHARACTERISTICS ................................................................................ 43 III.

ANALYTICAL VALIDATION ........................................................................................................................ 44

III.1. DEFINITIONS AND TERMINOLOGY ......................................................................................................... 44 III.1.1. Introduction ............................................................................................................................................ 44 III.1.2. Types of analytical procedures to be validated ....................................................................................... 44 III.1.3. Validation characteristics and requirements .......................................................................................... 45 III.1.4. Glossary .................................................................................................................................................. 46 III.2. METHODOLOGY .......................................................................................................................................... 47 III.2.1. Introduction ............................................................................................................................................ 47 III.2.2. Specificity ............................................................................................................................................... 48

III.2.2.1. Identification ............................................................................................................................................................ 48 III.2.2.2. Assays and impurity tests ......................................................................................................................................... 49

III.2.3. III.2.4. III.2.5.

III.2.5.1. Assay ........................................................................................................................................................................ 51 III.2.5.2. Impurities (quantification) ........................................................................................................................................ 51 III.2.5.3. Recommended data .................................................................................................................................................. 51 III.2.6.1. Repeatability ............................................................................................................................................................ 52 III.2.6.2. Intermediate precision .............................................................................................................................................. 52 III.2.6.3. Reproducibility ......................................................................................................................................................... 52 III.2.6.4. Recommended data .................................................................................................................................................. 52 III.2.7.1. Based on visual evaluation ....................................................................................................................................... 52 III.2.7.2. Based on signal-to-noise ratio .................................................................................................................................. 52 III.2.7.3. Based on the standard deviation of the response and the slope ................................................................................ 53 III.2.7.4. Recommended data .................................................................................................................................................. 53 III.2.8.1. Based on visual evaluation ....................................................................................................................................... 53 III.2.8.2. Based on signal-to-noise ratio .................................................................................................................................. 53 III.2.8.3. Based on the standard deviation of the response and the slope ................................................................................ 54

Linearity ................................................................................................................................................. 49 Range ...................................................................................................................................................... 50 Accuracy ................................................................................................................................................. 51

III.2.6. Precision ................................................................................................................................................. 51

III.2.7. Detection limit ........................................................................................................................................ 52

III.2.8. Quantitation limit.................................................................................................................................... 53

III.2.8.4. Recommended data .................................................................................................................................................. 54

III.2.9. Robustness .............................................................................................................................................. 54 III.2.10. System suitability testing ......................................................................................................................... 55 III.3. SPECIFIC APPLICATION TO METHODS USED IN THE PH. EUR. ......................................................... 55 III.3.1. Optical rotation (2.2.7.) .......................................................................................................................... 55

III.3.1.1. Introduction .............................................................................................................................................................. 55 III.3.1.2. Identification ............................................................................................................................................................ 55 III.3.1.3. Tests ......................................................................................................................................................................... 55 III.3.2.1. Identification ............................................................................................................................................................ 56 III.3.2.2. Limit test .................................................................................................................................................................. 56 III.3.2.3. Assay ........................................................................................................................................................................ 56 III.3.3.1. Appearance of solution (2.2.1. and 2.2.2.) ............................................................................................................... 57 III.3.3.2. Acidity or alkalinity ................................................................................................................................................. 57 III.3.3.3. Limit tests for anions/cations (2.4.) .......................................................................................................................... 57 III.3.4.1. Specificity ................................................................................................................................................................ 58 III.3.4.2. Calibration ................................................................................................................................................................ 58 III.3.4.3. Matrix effects ........................................................................................................................................................... 59 III.3.4.4. Detection and quantification limit (based on the standard deviation of the blank) ................................................... 59 III.3.5.1. Thin-layer chromatography (2.2.27.) ....................................................................................................................... 59 III.3.5.2. Liquid chromatography (2.2.29.).............................................................................................................................. 60 III.3.5.3. Gas chromatography (2.2.28.) .................................................................................................................................. 62

III.3.2. Ultraviolet spectrophotometry (2.2.25.).................................................................................................. 56

III.3.3. Non-instrumental limit tests .................................................................................................................... 57

III.3.4. Atomic absorption spectrometry (2.2.23.)............................................................................................... 58

III.3.5. Separation techniques ............................................................................................................................. 59

III.3.6.

III.3.7. III.3.8. Semi-micro determination of water (2.5.12.) .......................................................................................... 63 Volumetric titrations (2.5.11. - 2.2.19. - 2.2.20.) .................................................................................... 64 Peptide identification by nuclear magnetic resonance spectrometry (2.2.64.) ....................................... 66

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I. INTRODUCTION

I.1. PURPOSE OF THE GUIDE This document is a guide for the authors of monographs and also a means of communicating the principles for the elaboration of monographs to the users of the European Pharmacopoeia (Ph. Eur.), especially industry, licensing authorities and official medicines control laboratories. Since the principles applied and guidance given for the elaboration of monographs should be the same as those applied by licensing authorities, the Technical Guide may also serve as a guideline in the elaboration of specifications intended for inclusion in licensing applications.

It is necessary to bear in mind that a monograph will be a mandatory standard and must be applicable in licensing procedures in all Member States of the Convention on the Elaboration of a European Pharmacopoeia.

I.2. TEST PROCEDURES The methods chosen for the identification tests, purity tests and assay(s) constituting the bulk of a pharmacopoeial monograph are preferably those already described and utilised in the Ph. Eur.. In this context, the author of a monograph is referred not only to the General Methods of the Ph. Eur.. but also to published monographs on similar materials. The above considerations aim at ensuring a reasonable degree of harmonisation within the Ph. Eur. and they only apply in cases where the methods are found to be adequate for the specific purposes. However, due attention is also to be paid to the development of new methods that offer significant improvements in terms of sensitivity, precision, accuracy or discriminating power (selectivity).

Methods included in monographs must be validated as described in the chapter on analytical validation and other relevant specific chapters of this guide. Validation reports are provided to the EDQM but are not published or otherwise provided to users.

The test procedures included in a monograph should be verified in 2 or more laboratories and the laboratory reports on this verification should be provided to the EDQM to ensure future traceability.

The instructions describing any method of analysis cover all factors that can influence the results and that are deemed essential to enable an experienced analyst working according to acknowledged laboratory practices, yet without necessarily having any prior knowledge of the investigation in question, to perform the analysis. Variations in the description of similar methods are to be avoided.

If an analytical procedure is expected to be used generally or if it requires a lengthy description and is used more than once, it may be proposed for inclusion in the general chapters of the Ph. Eur., to be referred to in the individual monographs. The methods are prescribed on the scale conventionally applied in the Ph. Eur. except in cases where for reasons of availability of the material to be analysed, or because of its toxicity or its cost, work on a small scale would be advantageous.

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I.3. EQUIPMENT If the equipment utilised for a method of analysis is not generally available in the States party to the European Pharmacopoeia Convention, it must be possible to have it constructed according to its description in the Ph. Eur.

I.4. QUANTITIES In prescribing the quantities, i.e. masses and volumes, of substances, reagents, and solvents to be taken for identifications, tests and assays, it is the practice of the Ph. Eur. to indicate the accuracy with which they are to be measured (see General Notices). It is therefore necessary to take this aspect into consideration when drafting pharmacopoeial texts.

As guidance to minimise errors in the preparation of analytical solutions, Table 1, giving estimations of the relative uncertainty, is to be consulted.

In order to avoid either the use of extremely low amounts or an unnecessarily large expenditure of solvents, a dilution series will often have to be prescribed for the preparation of dilute solutions used particularly for spectrophotometric measurement. In this context not all combinations of (usually 2 or 3) dilution steps will contribute equally to the random error of the dilution procedure. If critical for the purpose, the optimal dilution is prescribed in consideration of the relative errors (capacity tolerance divided by nominal volume) associated with the various sizes of volumetric pipettes and volumetric flasks commonly used for these operations (taking the usual formula: square root of the sum of the squares of individual relative errors, to estimate the relative dilution error).

Tables giving the optimal number and nature of dilution steps needed to achieve a given dilution ratio, based upon given specifications for the capacity tolerances of volumetric glassware, are available in the literature. For guidance see Table 2 (it is to be noted that these factors do not include reading errors).