Development and Validation of a Rapid Chemometrics Assisted RP-HPLC with PDA Detection Method for the Simultaneous Estimation of Pyridoxine HCl and Doxylamine Succinate in Bulk and Pharmaceutical Dosage Form

Simple, rapid, precise, and accurate RP-HPLC method was developed and optimized with the help of chemometric tool for the simultaneous estimation of pyridoxine HCl and doxylamine succinate in bulk and pharmaceutical dosage form. Optimization was done by central composite design in response surface methodology. Based on the trial and error, percentage of organic phase (methanol) in mobile phase, flow rate, and molarity of the buffer were selected as factors. Resolution and retention time were used for the estimation of system response during the optimization procedure. The optimized condition was used and the separation was carried out on phenomenex C18 column (150 × 4.6？mm; i.d, 5？μ particle size) using the mobile phase containing 49.37% of methanol and 50.63% of phosphate buffer (45.14？mM) at a flow rate of 1？mL/min. Retention time was found to be 1.884 minutes for pyridoxine HCl and 3.959 minutes for doxylamine succinate. The calibration curves were found to be linear from 10 to 70？μg/mL and 10 to 90？μg/mL for pyridoxine HCl and doxylamine succinate with their correlation coefficient values 0.9995 and 0.9997. LOD and LOQ were found to be 23.5？ng/mL and 71.1？ng/mL for pyridoxine HCl and 99.9？ng/mL and 302.6？ng/mL for doxylamine succinate. 1. Introduction Pyridoxine hydrochloride (PYH) is chemically 3,4-pyridinediacetonitrile, 5-hydroxy-6-methyl, hydrochloride (Figure 1). It is a water-soluble vitamin, involved principally in amino acid, carbohydrate, and fat metabolism [1, 2]. Figure 1: Structure of PYH. Doxylamine succinate (DOX) is chemically N,N-dimethyl-2-[8-methyl-8-(2-pyridyl)？benzyloxy] ethylamine hydrogen succinate (Figure 2). It is an antihistaminic with antimuscarinic and pronounced sedative effect [1–3]. Figure 2: Structure of DOX. Literature survey exposed that there are few UV [1, 2, 4–7] and HPLC [2, 8–19] methods that were reported for these drugs individually and combined with other drugs. There is no article available in the literature regarding chemometrics approach used in the RP-HPLC method development for the simultaneous estimation of PYH and DOX. Developing and optimizing isocratic HPLC techniques [20] could be a sophisticated practice that needs synchronized fortitude of several factors. HPLC methods were optimized by time-consuming trial-and-error approach for the last several years, resulting only in an obvious optimum and information regarding the sensitivity of the factors on analytes separation and interaction between factors is not available. Hence, any one of the chemometric methods which includes the overlapping