Quality evaluation of simvastatin compounded capsules

Abstract

Simvastatin is commercially available as tablets and compounded capsules in Brazil. Very few reports regarding these capsules' quality, and consequently their efficacy, are available. The pharmaceutical quality of 30 batches of 20 mg simvastatin capsules from the market was evaluated by weight determination, content uniformity, disintegration (Brazilian Pharmacopeia), assay and dissolution test (USP32 tablet monograph). A HPLC method was developed for assay, content uniformity and dissolution test, and specifications were also established. Out of the 30 batches evaluated, 29 showed capsule disintegration within 45 min and individual weight variation was within ±10% or ±7.5% relative to average weight, for < or > 300 mg, respectively. Only 27 batches met dissolution test criteria with values >80% of the labeled amount in 45 min; 21 batches showed simvastatin content between 90.0-110.0% of the labeled amount and 19 batches had at least 9 out of 10 capsules with content uniformity values between 85.0-115.0% of the labeled amount with RSD<6.0%. Only 14 of all (30) batches fully met pharmacopeial quality standards. The establishment of test conditions and specification parameters for simvastatin capsules showed that there are relevant pharmacopeial quality differences between batches compounded by different pharmacies. For 53.33% of the tested products hypercholesterolemic treatment efficacy may be compromised.