An HPTLC densitometric method for simultaneous quantification of sorafenib tosylate and chrysin: Analytical method development, validation and applications

•Combination therapeutic strategy is a cornerstone of cancer therapy.•Sorafenib (SFN) and chrysin (CHR) demonstrate definitive synergistic potential.•Robust HPTLC method for simultaneous analysis of SFN & CHR in routine samples, plasma and SLNs.•Selection of apt solvent system and wavelength maxima for both molecules.•Validation of developed liquid chromatographic method as per ICH Q2R1 guidelines. Since decades, the plant bioactives have shown tremendous promise in the therapeutic management of cancer. Lately, many synthetic drugs and natural bioactive molecules have been used in combination for potential synergism in cancer therapeutics. Sorafenib (SFN) and chrysin (CHR) form one of such promising combinations with definitive synergistic potential in cancer therapy. This has, however, given rise to analytical challenges, as it becomes quite difficult to identify and quantify two or more active moieties simultaneously in the presence of each other. Herein, we report the development and validation of an HPTLC densitometric method for analysis of SFN and CHR, in combination, followed by studying the effect of biological matrix (i.e., plasma), on the assay of both the molecules. Solvent system, comprising of toluene: n-hexane: isopropyl alcohol (7:2:1), was employed for chromatographic separation with Rf values of 0.3 and 0.5, for SFN and CHR, respectively. Validation studies established linearity for the concentrations ranging from 20 to 800 ng/band for each of the molecules, along with high degree of accuracy, precision (intra- and inter-day), ruggedness, robustness, and sensitivity of the liquid chromatographic method. Specificity studies using plasma as the biological matrix, exhibited well-resolved peaks of both the molecules, coupled with high recovery values too. The aforesaid method was finally applied to the estimation of real plasma levels in Wistar rats, following co-administration of SFN and CHR as a suspension. In a nutshell, the validated analytical method can be productively applied for simultaneous estimation of SFN and CHR, for routine analysis, in drug formulations and in biological matrices like plasma.