Journal of Pharmaceutical Research International

Aim: Herb-drug interaction is a growing concern due to the increasing consumption of herbal medicines among populations globally. Assessment of potential interaction of herbs with concomitantly administered drugs is thus very necessary to ensure patient safety. The aim of this study was to determine the effect of Ciklavit^® on the in vitro release profile of proguanil tablets as indicator of potential in vivo herb-drug interaction.

Methodology: Physicochemical characteristics of proguanil tablets namely hardness, friability, weight uniformity, disintegration and chemical assay were evaluated as described in official compendia. In vitrodissolution of proguanil tablets was studied alone and with Ciklavit^® in three different dissolution media with pH 1.2, 4.5 and 6.8 respectively using USP dissolution apparatus II at 75 rpm. Analysis of proguanil was done using High Performance Liquid Chromatography coupled with a UV detector. Dissolution data was analyzed and percentage proguanil released in all dissolution media determined; dissolution profiles were compared using a model dependent approach – dissolution efficiency.

Results: Ciklavit® caused 51.6, 61.0 and 57.1% inhibition of proguanil release in vitro at gastro-enteric simulated pH 1.2, 4.5 and 6.8 respectively; this inhibition was statistically significant (P < .001). Release profiles for proguanil alone and proguanil with Ciklavit® showed difference in dissolution efficiency of 56.2%, 64.8% and 59.2% at pH 1.2, 4.5 and 6.8 respectively.

Conclusion: Ciklavit^® significantly decreased the dissolution of proguanil tablets at all simulated gastro-enteric pH studied. Further studies are needed to assess herb-drug interaction in vivo.