Nagham S. Turkey - Department of Chemistry, College of Science, University of Baghdad, AL-Jadria, Baghdad, IRAQ
Ghadah Fadhel - Department of Chemistry, College of Science, University of Baghdad, AL-Jadria, Baghdad, IRAQ

In this work, a highly accurate and sensitive method with low cost analyzer NAG/ADF/(۳۰۰-۲) homemade instrument coupled under continuous flow injection (CFIA) analysis was used to determine  promethazine hydrochloride in pure and pharmaceutical drug tablets. This method is dependent on the reaction between promethazine hydrochloride and phosphomolybdic acid (PMA) in the presence of ammonium chloride to form a brownish-yellowish ion-pair complex as precipitate. The turbidity of the formed complex has measured at an angle of ۰-۱۸۰° through the attenuation of incident light by precipitating. The chemical and physical parameters have been studied and optimized to enhance the sensitivity for the developed method of the promethazine hydrochloride-PMA-NH۴Cl system. The calibration curve of the proposed method was linear over the range ۰.۵-۳۰ mmole.L-۱ for both cells (Cell no.۱ and Cell no.۲), the detection limit for cell A = ۲.۱۶۵۹ µg/sample and for cell B = ۰.۴۳۳۲ µg/sample from the visual evaluation of the lowest concentration at which the analyte can be reliably detected with the correlation coefficient (r) = ۰.۹۹۸۴, ۰.۹۹۹۷ for cell A and cell B, respectively. For promethazine-HCl concentrations (۵ and ۱۰ mmole.L-۱) for both cells (n=۸), the relative standard deviation percent (RSD%) was lower than ۰.۵%. The method has been successfully applied for the promethazine HCl determination in two pharmaceutical medicines. A comparison was made using the standard addition curve between the newly proposed method (NAG-ADF-۳۰۰-۲ analyzer) and the reference methods, mainly British Pharmacopoeia (B.P), turbidimetry, and UV- spectrophotometry (λmax =۲۴۹ nm) using paired t-test. It was noticed that there was no significant difference between the methods at ۹۵% confidence level. The statistical procedures have shown that a homemade NAG/ADF/(۳۰۰-۲) analyzer which contains two identical detections units ( cell A and cell B) is the best choice with an excellent prolonged detection, widespread application and extra sensitive.

Promethazine hydrochloride, Flow injection analysis, Attenuated detection, Precipitation reaction