A flow analysis system integrating an optoelectronic detector for the quantitative determination of active ingredients in pharmaceutical formulations

Abstract

A simple, compact and low-cost optoelectronic detector was developed for complete turbidimetric measurements under continuous flow injection analysis. The device was fabricated by integrating white snow light-emitting diodes as a light source with solar cells as a detector (WLEDs-SCs) of attenuated light that is passed through the analyte. The device is made from ten of WLEDs and three solar cells only without any filters, lenses and fibers. The device operates according to the turbidimetric principle which measures the attenuated light at 180° of the incident light. The developed detector was adapted under flow injection analysis conditions and its real analytical utility has been successfully confirmed by validation and the development of a turbidimetric method for the quantitative determination of Cyproheptadine hydrochloride (CPH) in pure and pharmaceutical formulations. The proposed method is based on forming a turbid, yellow ion-pair association complex in a closed flow system as a result of a reaction between the drug and potassium chromate which was used as a precipitation reagent. Under optimized conditions, the analysis system offers linear range 2.2–160 µg ml−1 with a limit of detection at 0.6 µg ml−1, limit of quantification 1.8 µg ml−1 and correlation coefficient of 0.9986. The intra-day and inter-day precision for two serial estimations of 30 and 60 µg ml−1 of CPH exhibited a relative standard deviation of 0.94%, 0.29 and 0.68%, 0.21% respectively. While the accuracy of the proposed method has expressed as a recovery percentage (Rec %) and error % which were between 100.45–100.67 and 0.45% to 0.67% respectively. The proposed method has been successfully applied for the CPH determination in pharmaceutical preparations with high throughput tests (60 injections per hour) with no interference effect of the common excipients.