In vitro quality evaluation of brands of promethazine tablets marketed in Edo State, Nigeria

The increasing number of multisource pharmaceuticals has necessitated the need for continuous quality assessment of products available for atients’ consumption. Promethazine is an anti-histamine used in cases of nausea, vomiting, motion sickness etc. The study was to examine the in vitro quality parameters for ten brands of promethazine hydrochloride tablets sold in retail pharmacies in Edo State, Nigeria. The parameters determined were identification, weight variation, friability, hardness, disintegration, dissolution rate and assay. All samples were evaluated for conformity with British Pharmacopoeia (BP) 2017 standards. Results obtained showed tablet weight ranging from 0.08 g ± 1.77 % to 0.255 g ± 3.557 %, hardness from 4.36 ± 0.58 to 8.33 ± 3.21 kg/cm2, friability of < 1 %, disintegration time of 2.47 ± 0.90 to 69.66 ± 7.23 min and assay of 61.32 ± 2.04 to 183.19 ± 0.11%. The ten batches but one released more than 80 % of their drug content within 30 min. Analysis of similarity factor revealed other samples but PR-7 can be interchangeable with PR-1 based on dissolution profile. The results showed that not all samples examined passed all the pharmacopoeia tests for satisfactory quality. Thus, they all cannot be used interchangeably in clinical practice. Keywords: Promethazine; Quality Control; Dissolution; Pharmacopoeial specifications