Assessment of the quality of simvastatin capsules from compounding pharmacies

OBJECTIVE: To validate a method for determining the simvastatin content of compounded capsules, using high performance liquid chromatography. METHODS: Eighteen samples of simvastatin 40 mg capsules from compounding pharmacies in the cities of Sao Paulo, Guarulhos, Sao Bernardo do Campo and Campinas, Southeastern Brazil, prescribed for fictitious patients were assessed. The analyses were based on the Brazilian Pharmacopoeia and on the high performance liquid chromatography method, optimized and validated in accordance with national and international standards for identification and quantification tests on compounded capsules. RESULTS: The mean weight of the capsules ranged from 70 mg to 316 mg; four samples presented weight variation outside of the specification. The simvastatin content in the capsules was within the specification in 11 samples. In six, the content ranged from 4% to 87% of the declared quantity, thereby not complying with the content requirements for the active agent. For one sample, no content or uniformity determinations were performed. In the content uniformity test, 15 samples presented indices of less than 85%, with relative standard deviations greater than 6%. Three pharmacies had met the specification in this test. In the dissolution test, eight samples presented unsatisfactory results in the first stage of the test, while the remainder presented inconclusive results. CONCLUSIONS: The method used was shown to be suitable for application to quality control, and it revealed the poor quality of the simvastatin capsules produced by some compounding pharmacies.