Self-sealing capacity of vial stoppers after multiple needle punctures

To evaluate the self-sealing capacity of vial stoppers in two common radiopharmaceuticals after more than 10 needle punctures.

Assessment of self-sealing capacity was performed according to the self-sealing capacity test described in United States Pharmacopeial Convention (USP) General Chapter <381>. Groups of 10 vials of technetium (Tc)-99m sulfur colloid and Tc-99m tetrofosmin were tested for maintenance of self-sealing capacity following 10 punctures with 22-, 20-, and 18-gauge needles. Each vial was sequentially retested after additional sets of 10 punctures until failure of self-sealing capacity or until a total of 100 punctures, whichever came first.

The median number of needle punctures with maintenance of self-sealing ability before failure for 22-, 20-, and 18-gauge needles was >100 (range all >100), >100 (all >100), and 60 (30-90), respectively, for sulfur colloid and >100 (all >100), >100 (50 to >100), and 50 (20-70), respectively, for tetrofosmin. Incidentally, coring particles were observed frequently in vials after many punctures with 18-gauge needles, but infrequently with 20-gauge and rarely with 22-gauge needles.

Vial stoppers in two radiopharmaceutical products demonstrated robust self-sealing capacity, substantially exceeding the USP standard of 10 punctures with a 21-gauge needle. Coring particles were frequently observed after many punctures when using larger-bore needles but rarely when using smaller-bore needles. Under conditions commonly used, failure of self-sealing capacity and generation of coring particles are not anticipated to be problems encountered when puncturing vial stoppers of these two products substantially more than 10 times.