Validated Stability Indicating HPTLC and UV-Spectrophotometric Techniques for the Determination of Avanafil

Aims: To develop methods with complete validation according to ICH guidelines and to be applied for the determination of avanafil in pure form and in pharmaceutical formulation in the presence of its degradation products.

Study Design: High performance thin layer chromatography (HPTLC) and different spectrophotometric methods (dual wavelength, first derivative, first derivative of ratio spectra and ratio difference are developed for simultaneous determination of avanafil in laboratory-prepared mixtures of avanafil with its degradation products and in pharmaceutical formulation.

Place and Duration of Study: Sample: Department of Analytical Chemistry, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo, Egypt, between May 2019 and September 2019.

Methodology: Two techniques have been developed for the determination of avanafil in the presence of its degradation products. The first was HPTLC where separation was performed on silica gel 60 F254 plates, with chloroform: toluene: methanol: conc. ammonia (6:5:3:0.1, by volume) as a developing system and UV detection at 230 nm. The second one was UV- spectrophotometry which included dual wavelength between 267 and 292 nm, first derivative determination of the drug at 261 nm, first derivative of ratio of peak amplitudes at 275.6, 305.4 and 329 nm and the ratio difference with the amplitude difference between (266 and 250 nm).

Results: HPTLC method was applied over the concentration range of 0.5-5. μg/spot, while spectrophotometric methods were linear over the concentration range 5-50 μg/mL for avanafil.

Conclusion: Novel, simple and accurate method for the determination of avanafil in laboratory-prepared mixtures of avanafil with its degradation products and in pharmaceutical formulation.