The Ph. Eur. policy on Reference standards

Classification of reference standards • TYPE : • Chemical Reference Substances • Biological Reference Preparations • ESTABLISHMENT : • Primary standards • Secondary standards • PURPOSE : • QUALITATIVE (Id, system suitability) • QUANTITATIVE (Assay, external standard) © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

European Pharmacopoeia reference standards Chemical reference substance (CRS) A chemical compound or mixture of compounds which has been established for use as a standard in an identity test, a purity test and/or an assay as prescribed in a monograph. The standard is valid only for the specific test(s) for which it has been established © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

European Pharmacopoeia reference standards A European Pharmacopoeia reference standard is an integral and essential part of the monograph and as such is an official standard that is alone authoritative in case of doubt or dispute. © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Extent of analytical testing:according to the CRS use Identification => structure elucidation + compliance Peak ID, system suitability => structure elucidation + fitness for purpose External standard => structure elucidation + purity Assay: assignment based on interlaboratory study involving five laboratories: EDQM Laboratory + Official Laboratories and Experts; the manufacturer is normally invited to participate. © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Requirements for a candidate CRS Pharmaceutical Substance subject of a monograph: The CRS must comply with the requirements of the monograph, no special purity required. Impurity CRS (i.e. not subject of a monograph) Minimum content : qualitative use: 90%; quantitative use: 95% , otherwise value assigned © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

CRS for identification Compliance / structure elucidation : The EDQM laboratory carries out all tests of the monograph. The structure of the substance is elucidated by means of NMR, MS and FT-IR data as well as by comparison to literature data. © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Qualitative use System suitability Peak identification Quantitative use Limit test Quantitative test CRS used in the test for related substances © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

CRS used in the test for related substances In general an impurity is to be identified, i.e. located in the chromatogram or electropherogram: • when it has an individual limit and/or • when a correction factor must be applied © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Impurity CRS : qualitative use Individual impurity : preferred option but sometimes difficult to obtain • Mixtures of impurities • Batches containing one or more impurities • Spiked samples © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Info provided with a CRS Non-official information, intended to facilitate the use of the CRS can be found in the knowledge database (web site). © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Impurity CRS : quantitative use • Individual impurities, with an assigned value if necessary • Batch containing the impurity, with an assigned value © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Establishment of assay CRS:internal preliminary work • Elucidation of the structure of the candidate CRS • Verification of compliance with the monograph requirements • Additional tests, such as residual solvents, DSC purity, non-aqueous titration. © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Establishment of assay CRS:interlaboratory study • Protocol (method-specific approach) developed and checked in the EDQM laboratory • Samples out to the participants • Analysis of results • Report with proposed assigned value • Approval from the Group of Experts • Adoption by the Commission © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Example protocol: CRS for LC-assay Collaborative study: Loss on drying or det. of water (by KF / coulometry) Quantitative determination of the impurities by LC Residual solventsby head-space GC © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Establishment of assay CRS:Results acceptance criteria • Repeatability (water determination/ LOD) • Selectivity test (LC-GC) • Symmetry factor (LC-GC) • Repeatability (LC-GC) © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Estimation of the uncertainty of the assigned content Ph. Eur. Commission policy : the uncertainty of the value assigned as a result of an interlaboratory trial should be within a predetermined limit which is calculated in relation with the intended use . © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Content If the CRS is supplied as a powder to be weighed, the value assigned is the % (m/m) content on an «as is» basis. NO NEED TO DRY. Example: Benzathine benzylpenicillin CRS 2 © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Content If the CRS is supplied in a pre-dispensed form such as a freeze-dried substance to be reconstituted, the value assigned is the quantity per vial. Example: Calcitonin (salmon) CRS 5 © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Use of Ph. Eur. CRS • Ph. Eur. CRS are to be used in conjunction with the corresponding monograph(s). • Ph. Eur. CRS are to be used for the purpose for which they are intended. • Any different use is in the responsibility of the user. • Storage of opened containers is discouraged and is in any case the responsibility of the user. © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Monitoring programme Once established and adopted, the CRS undergoes periodic testing in order to ensure its continuous fitness for use. The periodicity of testing depends on the use of the CRS and the stability information available. The extent of testing depends on the use of the CRS. In general the focus is on the properties that may change during the life cycle of a CRS, i.e.: appearance, purity by HPLC or GC, DSC, water content. © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Reference standards database Availability Origin Assigned Value Batch Validity Statement Safety Data Sheets Info on reagents and columns Chromatograms Knowledge database © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

New Chapter of the European Pharmacopoeia5.12 Pharmaceutical Reference Standards Effective Jan 1st, 2007 ESTABLISHMENT USE PRESENTATION of pharmaceutical reference standards in general & European Pharmacopoeia reference standards in particular. © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

Impurity Reference StandardsNew opportunities / Development Areas The Challenge: The new Ph. Eur. policy on Impurities requires that most if not all the specified impurities be identified. Our Strategy: Develop new compounding/dispensing techniques Hyphenated techniques for establishment New rapid techniques for monitoring Keep no. of CRS/monograph as low as possible Keep price reasonable © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

They are official, primary standards They constitute an essential part of the monograph They are guaranteed only for the intended purpose The assay value is assigned “as is” Their continuous fitness for purpose is assured by a regular monitoring programme User interface => website The Ph. Eur. policy on reference standard is reflected in general chapter 5.12 Ph. Eur. CRS take home messages © AL IPA/EDQM/IDMA Symposium 2007, All rights reserved

The Ph. Eur. policy on Reference standards