Flow-injection chemiluminometric analysis of some benzamides by their sensitizing effect on the cerium-sulphite reaction.

A simple, highly sensitive chemiluminescent method using flow injection is described for the determination of three substituted benzamides, namely: sulpiride, sultopride and tiapride. The method is based on the sensitizing effect of these drugs on the chemiluminometric oxidation of sulphite by cerium(IV). The different experimental parameters affecting the chemiluminescence intensity were carefully studied and incorporated into the procedure. The method permits the determination of 0.05-2.5 mug ml(-1) sulpiride, 0.01-2.5 mug ml(-1) sultopride hydrochloride and 0.01-1.5 mug ml(-1) tiapride hydrochloride with minimum detectability of 0.01 mug ml(-1). The method was applied to the determination of these benzamides in pharmaceutical preparations and biological fluids.

Complexometric-spectrophotometric assay of tetracyclines in drug formulations.

An accurate, rapid and very simple spectrophotometric method for the assay of tetracyclines (tetracycline.HCl, chlorotetracycline.HCl, demeclocycline, oxytetracycline.HCl and doxycycline) has been developed. The method is based on the complexation of iron(III) with tetracyclines in 0.001M sulphuric acid. It has been successfully applied to the assay of tetracyclines in drug formulations, and the interferences of excipients have been examined. The results have been statistically compared with those obtained by two standard methods and found to be very satisfactory.