RP-HPLC-based simultaneous quantification and stability assessment of doxycycline hyclate and aloe-emodin in lipid nanocarriers

Abstract

A novel simultaneous estimation and stability-indicating RP-HPLC method was developed and validated for the simultaneous quantification of doxycycline hyclate and aloe-emodin in blend and in novel nanostructured lipid carriers. The mobile phase comprised a phosphate buffer to methanol at ratios of 40:60 (v/v) and 70:30 (v/v), both at pH 8, for the separation of doxycycline hyclate and aloe-emodin, respectively. Detection was performed using a PDA-M20A photodiode array detector at a lambda of 268 nm (doxycycline hyclate) and 250 nm (aloe-emodin). The method was validated according to the instructions of ICH guidelines for precision, accuracy, linearity, specificity, limit of detection, and limit of quantitation. The developed method exhibited linearity in the concentration range of 5–30 µg/mL for both analytes. The limit of detection and limit of quantitation were estimated to be 0.0279 µg/mL and 0.0846 µg/mL for doxycycline hyclate and 0.0262 µg/mL and 0.0795 µg/mL for aloe-emodin, respectively. Accuracy, as estimated by percent recovery, ranged from 180.37% to 216.52% for doxycycline hyclate and from 180.17% to 214.59% for aloe-emodin, depicting high recovery values. Forced degradation studies under five distinct stress conditions depict the competency of the method. The present study explored the simultaneous measurement of aloe-emodin and doxycycline hyclate in the novel nanostructured lipid carriers based gel. The technique demonstrated excellent specificity, accuracy, and sensitivity, with distinct retention times and well-defined peaks for each drug and its degradation products.