SEQUENTIAL INJECTION-ANALYSIS TECHNIQUE FOR THE CONCENTRATION, STOICHIOMETRY AND FORMATION CONSTANT STUDIES OF PROMETHAZINE HYDROCHLORIDE COMPLEXED WITH PALLADIUM(II) IN HYDROCHLORIC-ACID

The sequential injection analysis (SIA) technique was successfully app lied to the determination of promethazine hydrochloride in drug formul ations, The chemical system is based on the complexation reaction of p romethazine hydrochloride with Pd-II in 8.0 X 10(-4) mol dm(-3) HCl an d measurement of the absorbance at 504 nm, Promethazine was determined in the range 50-400 ppm using 1.0 x 10(-3) mol dm(-3) Pd-II with an a spiration volume of 147.5 mu l. The SIA technique was utilized for the determination of the concentration, stoichiometry and formation const ant of the complexation reaction, The technique was found to be superi or to flow injection analysis, The SIA method was statistically compar ed with the official British Pharmacopoeia method and showed comparabl e accuracy, but with the advantages of selectivity, simplicity, speed and amounts of reagents consumed.