Sesardic D, Winsnes R, Rigsby P, Gaines-Das R
NIBSC, South Mimms, Potters Bar, Hertfordshire ENG6 3QG, UK.
Pharmeuropa Spec Issue Biol. 2001 Aug;2001(1):45-72.
The aim of the present collaborative study was to calibrate two candidate replacement standards for tetanus vaccine for human use in the terms of the Second International Standard (IS) for Tetanus Toxoid, Adsorbed (TEXA-2) using challenge potency assays in guinea pigs and mice and to establish the 3rd IS and the Ph. Eur. BRP batch 2. Two test preparations (coded B and C) were included as candidate replacement for TEXA-2 and Ph. Eur. BRP batch 1 (EBRP-1). This project was run as a joint WHO/Ph. Eur. study. Twenty-seven laboratories representing nineteen countries participated in the study. Twenty-three laboratories performed assays in mice (11 laboratories performed lethal, 11 paralysis, and one serology assays) and fourteen laboratories performed assays in guinea pigs (10 laboratories performed lethal and 4 paralysis assays). Estimates of potency, expressed in ampoule of TEXA-2 per ampoule of candidate replacement standards were two-fold higher in mice than in guinea pigs. However, using the assumed relationship between TEXA-1 and TEXA-2 in mice and guinea pigs (Lyng and Nyerges, 1984), potency estimates for candidate replacement standards (sample coded B and C), in terms of TEXA-1, gives estimates which are similar in both animal models. Stability was assessed within the collaborative study for candidate standard B. On the basis of this collaborative study, the ECBS of WHO has established the candidate material coded B as the Third IS for Tetanus Toxoid, Adsorbed, with an assigned unitage of 469 IU/ampoule, based on its calibration by guinea pig challenge assays (WHO report BS/00.1932). Further studies were organised to assess which of the two candidate standards is most suitable as replacement for EBRP-1. Manufacturers were asked to include candidate B and candidate C in their routine quality control potency assays of tetanus vaccines in order to assess the impact of the use of either preparation on their calibration results. The features and results of this additional phase are described at the end of this report in a separate section entitled "Choice of replacement batch for EBRP-1". Based on these results, at the session in March 2001, the Ph. Eur. Commission adopted candidate B as the Tetanus vaccine (adsorbed) Ph. Eur. BRP Batch 2 with assigned potencies of 469 IU/ampoule for the guinea pig assays and 496 IU/ampoule for the mouse assays.
本合作研究的目的是，通过在豚鼠和小鼠身上进行效价测定，以吸附破伤风类毒素第二国际标准（IS）（TEXA - 2）为参照，校准两种供人类使用的破伤风疫苗候选替代标准品，并建立第3个国际标准品和欧洲药典参比制剂批次2。两种试验制剂（编号为B和C）作为TEXA - 2和欧洲药典参比制剂批次1（EBRP - 1）的候选替代品。该项目作为世界卫生组织/欧洲药典联合研究开展。来自19个国家的27个实验室参与了该研究。23个实验室在小鼠身上进行了测定（11个实验室进行致死试验，11个实验室进行麻痹试验，1个实验室进行血清学试验），14个实验室在豚鼠身上进行了测定（10个实验室进行致死试验，4个实验室进行麻痹试验）。以每安瓿候选替代标准品相当于多少安瓿TEXA - 2表示的效价估计值，在小鼠身上比在豚鼠身上高两倍。然而，利用小鼠和豚鼠身上TEXA - 1与TEXA - 2之间的假定关系（Lyng和Nyerges，1984年），以TEXA - 1为参照的候选替代标准品（样品编号为B和C）的效价估计值，在两种动物模型中相似。在合作研究中对候选标准品B的稳定性进行了评估。基于该合作研究，世界卫生组织生物标准化专家委员会已将编号为B的候选材料确立为吸附破伤风类毒素第3个国际标准品，根据豚鼠攻毒试验校准，其指定效价为469 IU/安瓿（世界卫生组织报告BS/00.1932）。组织了进一步研究，以评估两种候选标准品中哪一种最适合替代EBRP - 1。要求生产商在其破伤风疫苗的常规质量控制效价测定中纳入候选B和候选C，以便评估使用任何一种制剂对其校准结果的影响。本报告结尾在题为“EBRP - 1替代批次的选择”的单独章节中描述了这一附加阶段的特点和结果。基于这些结果，在2001年3月的会议上，欧洲药典委员会采用候选B作为欧洲药典吸附破伤风疫苗参比制剂批次2，豚鼠试验的指定效价为469 IU/安瓿，小鼠试验的指定效价为496 IU/安瓿。
