Triamcinolone acetonide concentration after filtration of the solvent agent.

Purpose: To determine the amount of triamcinolone acetonide and the preservative benzyl alcohol after filtration.

Design: Laboratory investigation.

Methods: The probes were prepared by two different hospital pharmacies. The probes of the first pharmacy included 20 probes with 25-mg triamcinolone acetonide, unfiltered (n = 5 probes) or filtered (n = 5), or with 4-mg triamcinolone acetonide, filtered (n = 5) or unfiltered (n = 5). The probes for the second pharmacy were filtered (n = 3) probes of 25-mg triamcinolone acetonide.

Results: For the probes of the first pharmacy, triamcinolone acetonide dosages were 2.4 +/- 0.8 mg, 3.1 +/- 0.6 mg, 12.8 +/- 0.7 mg, and 23.4 +/- 2.3 mg, respectively, for the filtered 4-mg probes, unfiltered 4-mg probes, filtered 25-mg probes, and unfiltered 25-mg probes, respectively. For the second pharmacy, mean triamcinolone acetonide dosage was 23.8 +/- 0.6 mg for the 25-mg filtered probes and contained benzyl alcohol in a mean concentration of 0.0013 +/- 0.0001 mg/0.1 ml.

Conclusions: Depending on the method employed and the pharmacy, preparation of triamcinolone acetonide including filtration of the solvent agent leads to a marked inter-pharmacy variation and a relatively low intra-pharmacy variation in the reduction of triamcinolone acetonide dosage.