<i>In vitro</i> evaluation of the quality control parameters of six brands of sustained release nifedipine tablets

Abstract

An in vitro evaluation of the quality control parameters of six brands of sustained release nifedipine tablets (coded NIF-A __ NIF-F) was conducted to ascertain their pharmacopoeia compliance. Their respective manufacture and expiry dates, product registration status, country of origin as well as label claim of potency were noted. Total drug contents of respective samples were determined with the high performance liquid chromatography (HPLC). Tablet weight, hardness, disintegration and friability were assessed using the British Pharmacopoeia methods. The dissolution profile was determined using USP Apparatus 2 at 50 rpm and 37±0.5˚C in 900 ml of phosphate buffer for 8 h. A 5 mL of sample was withdrawn at hourly intervals and analyzed using UV spectrophotometer at 275 nm. Results show that physical parameters of the respective brands of nifedipine tablets studied were within pharmacopeia acceptable limits. Total drug content for all the samples fell within the USP requirement of 90- 110 %. The dissolution requirements for nifedipine extended release tablets are specified in the United States Pharmacopoeia. The fraction of drug dissolved using the USP apparatus at 50 rpm is specified for nifedipne ER tablets as 10 – 30 % ( 2- 6 mg) release after 3 hrs; 40 – 65 % ( 8- 13 mg) after 6 hrs. Based on this condition, only brands B and C fulfilled the USP requirement for drug dissolution.

Keywords: In vitro, quality control, nifedipine, sustained release, tablet