Quality assessment of five brands of loperamide hydrochloride marketed in Awka capital territory Nigeria

Loperamide hydrochloride (LH) is widely used for the symptomatic control of diarrhoea but there is concern with regards to the efficacy and safety of the diverse generic brands currently in use. Five brands (A, B, C, D and E) of LH were evaluated using uniformity of weight, disintegration time and dissolution time tests as well as HPLC assay.  The paddle method was used for the dissolution test, while the High-Performance Liquid Chromatography (HPLC) was used to determine the quantity of Loperamide hydrochloride in each capsule. 
Brands A, B, D and E passed the uniformity of weight test according USP specifications, whereas brand C failed. Brands A, B, D, and E disintegrated rapidly within 3–7 minutes, demonstrating efficient breakdown of the capsule shell. Brand C however, had a prolonged disintegration time of up to 32.5 minutes. The USP (United States Pharmacopeia) maximum disintegration time is 30 minutes for capsules. Brands A and D had the fastest and most complete dissolution, reaching nearly 100% at 45 minutes. Although brands B and E released the drug slowly, they still achieved acceptable levels. However, brand C exhibited the lowest drug release, reaching only 54 % after 45 minutes. The HPLC assay revealed brands A, B, D and E had percentage mean peak area that fell between 90-110 %, (USP allowed range) while brand C had 79.28 %. Hence brand C Loperamide also failed this test. 
Conclusion: Brand C Loperamide hydrochloride did not meet most of the USP specifications.