Spectrophotometric studies of reactions between pseudo-ephedrine with different inorganic and organic reagents and its micro-determination in pure and in pharmaceutical preparations

Two simple, sensitive, cheep and reliable spectrophotometric methods are suggested for micro-determination of pseudoephedrine in its pure form and in pharmaceutical preparation (Sinofree Tablets). The first one depends on the drug reaction with inorganic sensitive reagent like molybdate anion in aqueous media via formation of ion-pair mechanism. The second one depends on the drug reaction with π-acceptor reagent like DDQ in non-aqueous media via formation of charge transfer complex. These reactions were studied under various conditions and the optimum parameters were selected. Under proper conditions the suggested procedures were successfully applied for micro-determination of pseudoephedrine in pure and in Sinofree Tablets without interference from excepients. The values of SD, RSD, recovery %, LOD, LOQ and Sandell sensitivity refer to the high accuracy and precession of the applied procedures. The results obtained were compared with the data obtained by an official method, referring to confidence and agreement with DDQ procedure results; but it referred to the more accuracy of the molybdate data. Therefore, the suggested procedures are now successfully being applied in routine analysis of this drug in its pharmaceutical formulation (Sinofree) in Saudi Arabian Pharmaceutical Company (SPIMACO) in Boridah El-Qaseem, Saudi Arabia instead of imported kits had been previously used.

The pseudoephedrine (Psed) reactions molybdate and DDQ reagents respectively were studied spectrophotometrically at optimum conditions of solvents, reactant concentration, temperature, time, λmax and pH. Application of the molar ratio method (MRM) on the Psed–molybdate ion-pair is given by,Figure optionsDownload as PowerPoint slideHighlights
► Inorganic and organic reagents are successfully applied for microdetermination of pseudoephedrine.
► Drug-molybdate and DDQ ion-pair and CT-complex, were studied spectrophotometrically.
► These methods are developed to displace kits in Saudi Arabian Pharmaceutical Company (SPIMACO).