Quality evaluation and UV spectrophotometric assay of ten brands of amlodipine tablets marketed in Uyo, Nigeria

Abstract

Amlodipine is a calcium channel blocker that is widely used to treat hypertension, which is a chronic health condition characterized by persistent elevated pressure of blood in the arteries. Hypertension is a predisposing factor to stroke, kidney failure, heart diseases and vision loss. The large demand for amlodipine makes it a good candidate for fakers. Consumption of substandard and/or fake amlodipine tablets will have a negative impact on the management of hypertension. This justifies continuous monitoring of amlodipine preparations in the marketplace and the provision of simple and cost-effective assay method that could be routinely utilised for their assay. Ten different brands of amlodipine 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 240 nm. 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 and nine brands passed the dissolution test. The spectrophotometric assay showed that all the brands passed the United States Pharmacopoeia (USP) requirement for percentage drug content. The assay method used in this study is reliable, simple and cost- effective and can be routinely used to assay amlodipine tablets. Keywords: Amlodipine, qualitative, quantitative, assay, ultraviolet spectrophotometry