Spectrophotometric determination of ethchlorvynol, methylpentynol carbamate and lynestrenol

ABSTRACT

A sensitive direct spectrophotometric procedure is described for the determination of two monoacetylenic compounds namely; ethchlorvynol and methylpentynol carbamate which are used as hypnotics and sedatives. The procedure is based on the direct spectrophotometric measurement of ethanolic solutions of the concerned compounds at 230 nm and 235 nm, respectively. The procedure is also applied for the determination of placidyl capsules [ethchlorvynol] and N-oblivon tablets [methylpentynol carbamate] with mean percentage accuracies; 100.7 +or- 0.65 and 97.3 +/- 1.18 respectively. The absence in literature of any more direct spectrophotometric procedures for the determination of lynoestrenol except in the vacuum U.V. Region which are apt to many interferences. However, a barely perceptible shoulder far from the vacuum U.V. region, almost centered at 242 nm is observed in the zero-order spectrum of lynoestrenol. This made use of in the determination of lynoestrenol applying the first-derivative technique with a mean percentage accuracy 98.03 +/- 1.114. The first- derivative technique is still retained the accuracy and precision when applied to tablets containing lynoestrenol with a mean percentage accuracy of 98.2 +/- 0.694, with a further significant advantage that no preliminary extraction of the tablets is needed