SOLID-SURFACE ROOM-TEMPERATURE PHOSPHORIMETRY ANALYSIS OF YOHIMBINE HYDROCHLORIDE IN PHARMACEUTICAL FORMULATIONS

A new method of analysis for yohimbine hydrochloride pharmaceutical formulations is reported. The phosphorescence characteristics of yohimbine hydrochloride were studied at room temperature employing low background paper substrate. The use of phosphorescence enhancers such as sodium iodide, thallium(I) nitrate, and sodium dodecyl sulfate were optimized to obtain limits of detection at the nanogram level. The interference effects of active ingredients commonly encountered in yohimbine hydrochloride formulations were also evaluated. These included methyl testosterone, strychnine hydrochloride, and tocopherol acetate. The recovery of the method was tested in commercial formulations containing yohimbine hydrochloride and tocopherol acetate. The analyses were performed by both the calibration curve and the standard addition procedure. The recoveries obtained varied from 93.61 +/- 3.15% to 101.53 +/- 11%. The simplicity, the sensitivity, and the selectivity of the method, associated to the satisfactory recoveries obtained, show the potential of solid surface room temperature phosphorimetry for the analysis of yohimbine hydrochloride formulations.