Development and Certification of Calcium Chloride Casein Reference Standard

Abstract

In accordance with the requirements of the State Pharmacopoeia of the Russian Federation, 14th edition, Clostridium novyi 198 test strain is used to determine growth promoting properties of thioglycollate medium when testing sterility of immunobiological medicinal products. The preservation of C. novyi 198 as spores requires a special liquid medium containing insoluble calcium chloride casein (CChC). At present, there is no reference standard available on the Russian market for the quality control of CChC used as a component of the media for preservation of C. novyi 198.The aim of the study was to develop and certify the first batch of calcium chloride casein industry reference standard (IRS) for the quality control of CChC batches and liquid media containing CChC which is used to preserve C. novyi 198 as spores.Materials and methods: thermally denatured CChC which was chemically synthesized from industrial CChC was used as candidate material. The quality control was performed using the test procedures described in procedural guidelines MUK 4.2.2316-08. C. novyi 198 spores were obtained as described in the «Sterility testing» section of MUK 4.2.2316-08 (preparation, inoculation and incubation in the medium containing calcium chloride casein IRS).Results: a list of quality parameters was developed for calcium chloride casein IRS: «Spore formation» (certifiable parameter), «Appearance», «Loss on drying», «Clarity of medium». The first batch of the candidate calcium chloride casein IRS was certified. The value of the «Spore formation» certifiable parameter was found to be (32.6 ± 7.3) %, the IRS shelf life was 5 years when stored in a dry place protected from light at a temperature of 15 to 25 °C. A documentation package for the IRS 4228-444-2018 was prepared and approved. The liquid medium containing CChC reference material (0.3 g/10 mL) allows for preservation of the biological properties of the C. novyi 198 working culture for at least 12 months.Conclusions: the certification results demonstrate that the calcium chloride casein IRS meets the applicable requirements and can be used as reference material to control the quality of new CChC batches and to assess the suitability of liquid medium containing CChC for preservation purposes. The use of the calcium chloride casein IRS makes it possible to standardise and greatly simplify the procedure for preserving the stability of C. novyi 198, to increase the efficiency and reliability of immunobiologicals quality control in terms of Sterility, and to reduce costs when using a freeze-dried strain.