Influence of some parameters on the approximation of European Pharmacopoeia and ISO Standard 4802: reasons for harmonisation - A collaborative study of ICG/TC2, 'Chemical Durability, and Analysis'

The most, widely used Standards to test the inner surface of glass containe rs for pharmaceutical use, European Pharmacopoeia and ISO 4802, may differ significantly, in the results because of relevant differences in the proced ures. In this study the rinsing procedures, effect of prolonging the coolin g time to 95 degrees C, as prescribed by EN norms on safe operation practic e and the combination of the two factors were investigated. Nine laboratori es participated ill the collaborative study the resulting extract solutions were analysed both by titration and flame photometry. Results were evaluat ed by two way ANOVA with the aim of estimating three sources of variation: between procedures, between laboratories and random variation due to experi mental error: For soda-lime-silica glass there is evidence that the differe nt procedures irfluence the hydrolytic resistance of the inner surface of g lass containers, whichever method is used. Differences between laboratories were, however; much greater and results vary more due to which laboratory conducted the measurement rather than which procedure is employed. For boro silicate glass variations between procedures were found not to be significa nt. It is strongly, recommended that ISO and EP shall adopt measures to min imise those factors that proved to exert great influence on reproducibility of results.