Quality Assessment of Various Brands of Lisinopril Tablets sold in Uyo Metropolis using UV Spectrophotometry

Abstract

Lisinopril is an angiotensin-converting enzyme inhibitor (ACEI) used for the management of hypertension. The danger of use of substandard and/or fake lisinopril tablets for management of hypertension cannot be over-emphasised. It will lead to negative treatment outcomes. This necessitates the quality assessment of the different brands of lisinopril marketed and the provision of simple and cost-effective method of assay that will encourage regular and quick sampling. Ten brands of lisinopril tablets were qualitatively assessed for uniformity of weight, friability, hardness, disintegration and dissolution rate using standard physical methods. Quantitative assay was carried out using spectrophotometric method. The spectrophotometric measurement was done at a wavelength of 340nm. Seven brands met the official requirements for uniformity of weight; eight passed the friability test and the hardness tests. All the brands tested passed the disintegration test while only four brands passed the dissolution test. The calibration curve for reference lisinopril in methanol was linear over a concentration range of 0.00-0.1?g/ml. The variation of absorbance with concentration showed correlation with coefficient of correlation (r) of 0.994 and coefficient of determination (r2) of value 0.985. Seven brands passed the British Pharmacopoeia (BP) requirement for percentage drug content of lisinopril (92.5-105.0%). The assay method used in this study is reliable, simple and cost-effective and can be routinely used to assay lisinopril tablets.