Flow injection potentiometric determination of Chlorphenoxamine Hydrochloride

Novel RP-HPLC-DAD approach for simultaneous determination of chlorphenoxamine hydrochloride and caffeine with their related substances

Ensuring the quality control of active pharmaceutical ingredients is crucial for drug products being introduced into the market. Even for established drugs, it is necessary to maintain a cutting-edge impurity control system. To analyze caffeine and chlorphenoxamine hydrochloride in their binary mixture, as well as theophylline and chlorphenoxamine N-oxide as related substances, a reversed phase-high performance liquid chromatography combined with a diode array detector system was created. The chromatographic separation was conducted using a C18 X-select Waters® column. The mobile phase consisted of 20.0 mM potassium dihydrogen phosphate modified to pH 3 with o-phosphoric acid and methanol. A gradient elution program was adopted at a flow rate of 1.3 mL/min and detected at a wavelength of 222 nm. The present methodology demonstrates a concentration ranging from 2-60, 1-80, 0.5-20 to 0.4-20 µg/mL for chlorphenoxamine hydrochloride, caffeine, chlorphenoxamine N-Oxide and theophylline, respectively. Chlorphenoxamine N-Oxide, being an impurity of chlorphenoxamine was prepared by refluxing intact drug with 5% H2O2 for 24 h at 100 °C. One of the objectives of the analytical community is to promote the adoption of green analysis methods, which involve the development of environmentally friendly techniques. The levels of greenness and whiteness were evaluated using four specific tools: Eco-Scale System, GAPI, AGREE, and RGB tool. Furthermore, we have evaluated the greenness of the analytical method presented and compared its performance and greenness to that of the approach described in the literature. In this study, results from CPX and CAF analysis were compared to those obtained in a previous study. The result shows that there is no notable variation in precision and accuracy. The proposed method was validated in accordance with the requirements of ICH.

Dissolution testing and potentiometric determination of famciclovir in pure, dosage forms and biological fluids

The performance characteristics of two new plastic membrane ion selective electrodes (ISEs) used for the determination of famciclovir (Fcv) based on the ion associate of Fcv with phosphotungstic acid (PTA) or phosphomolybdic acid (PMA) are described. Different experimental conditions as type of plasticizer to be incorporated in the membrane, life span, effect of soaking, pH, temperature, and interferences were studied. Both electrodes showed similar performance under these conditions, exhibiting Nernstian slopes of S (Fcv-PTA)=58.60±0.84 mV/decade and S (Fcv-PMA)=58.77±0.68 mV/decade within a usable concentration range of 10⁻⁵-10⁻² [Fcv/M] at 298/K. Famciclovir was assayed potentiometrically in its pure solution, pharmaceutical preparations and biological fluids (urine and plasma) using proposed electrodes under batch and flow injection analysis (FIA) conditions with a recovery % ranging between 96.76% and 102.83% having RSD of 0.66%-1.81%. The electrodes were also successfully applied in the determination of the dissolution profile of Fcv tablets and the results came in agreement with the validated results of the HPLC method obtained from the quality control unit of the company producing the tablets.