Development and Validation of an HPLC Method for Simultaneous Determination of Miconazole Nitrate and Chlorhexidine Digluconate in Chitosan-Based Gel Formulations

Miconazole nitrate (MN) and chlorhexidine digluconate (CHX) are the commonly used antimicrobials for topical treatment of dermal infections. Combination of antimicrobials has been investigated to enhance the efficacy of the treatment. Gel formulations based on bioadhesive polymers are preferred for delivery of these drugs. Chitosan is a promising bioadhesive polymer due to its penetration enhancing, antimicrobial and tissue healing properties. Yet, most of the gel-based formulations present analytical challenges during testing the drug content. It was aimed to develop an HPLC method for simultaneous determination of MN and CHX in chitosan-based gel formulations. Different solvent combinations were investigated for extraction of drugs from the gels. HPLC conditions such as mobile phase, flow rate, run time, column temperature and wavelength were explored. The method was validated according to ICH guideline Q2(R1). MN and CHX were extracted in solvent composition same with the mobile phase. The method was employed on ACE-C8 column at 40°C by isocratic elution using the mobile phase consisting of methanol:phosphate (75:25 v/v) buffer (containing triethylamine). Flow rate was 1 mL/min. The drugs were detected at 254 nm (CHX) and 230 nm (MN). Linearity was obtained between 5 to 80 μg/mL for both drugs. LOD and LOQ obtained for CHX was 1.61 and 1.06, for MN: 4.87 and 3.21 µg/mL, respectively. A new validated HPLC method was developed for simultaneous determination of CHX and MN in chitosan-based gels, with 98 to 102% recovery, without any interference with the excipients.