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

Interaction of Surface Active Drug Promethazine Hydrochloride with Surfactants: Drug Release from Microemulsions

The interaction of surface-active drugs with surfactants, used in the simulation of artificial membranes by direct and reversed micelles, mainly determines the transport of drugs in the body and the complex process of the binding to receptors. Besides, the delivery of drugs into the body via microemulsions has been successfully used to reduce the first-pass metabolism. The structure of mixed reverse microemulsions based on the ionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and the cationic surface active drug promethazine hydrochloride (PMT) was studied spectroscopically in the infrared and UV-visible regions, as well as using electrical conductivity and dynamic light scattering. The release profile of PMT from AOT-based microemulsions was studied using cellulose dialysis bags. The introduction of PMT additive into the water pockets of reverse AOT micelles leads to: a) an increase in free water fraction and a decrease in bound water fraction; b) changing the chromatographic retention factors of the model compounds; c) insignificant influence on the values of the binding constant of optical probe o-nitroaniline with the head groups of AOT; d) quenching of water-induced percolation in electrical conductance of reverse AOT microemulsions; e) a slight decrease in the size of water droplets at the same values of the molar ratio of water/surfactant. The release of PMT from the aqueous system obeys Fick’s law of diffusion (n = 0.4852), and the release of PMT from microemulsions is based on non-Fickian or anomalous diffusion.