PDA journal of pharmaceutical science and technology

Comprehensive determination of extractables from five different brands of stoppers used for injectable products.

PMID 20169859


Five commonly used stopper formulations were tested for extractables using three different vehicles (pH 3 citrate buffer with 20% w/v sulfobutylether-beta-cyclodextrin, pH 8 phosphate buffer and 50/50 v/v polyoxyethylated castor oil/dehydrated alcohol). The stoppers, made from butyl and halobutyl rubbers, coated and uncoated with proprietary films, were stored in contact with each vehicle for up to 6 months at 40 degrees C/75% relative humidity (RH) or for up to 24 months at 25 degrees C/60% RH. Samples were analyzed for the presence of extractables using inductively coupled plasma-atomic emission spectroscopy, ion chromatography, high-performance liquid chromatography, and gas chromatography. Extractables were observed at greater than 10 ppm for only one of the five stoppers that were tested. Based on these results, a standardized protocol for stopper extractable testing was developed. This protocol has been used to satisfy stopper extractable testing regulatory requirements for a number of different new injectable products.