Validated HPTLC Method for Simultaneous Estimation of Dihydroartemisinin and Piperaquine Phosphate in Pharmaceutical Dosage Form

Asimple, precise and accurate high performance thin layer chromatography (HPTLC) method has been developed for the simultaneous estimation of dihydroartemisinin and piperaquine phosphate in pharmaceutical dosage form. The separation was carried out on Merck TLC aluminum sheets with silica gel 60 F₂₅₄, (20 × 10 cm) of 250 μm thickness using chloroform–methanol–ammonia 25% (9.5 : 0.3 : 0.1, v/v) as the mobile phase. HPTLC separation of the two drugs followed by optical densitometry measurement of their spots at 345 nm for piperaquine phosphate before derivatization and 545 nm for dihydroartemisinin after derivatization was done. Derivatization was performed using a mixture of anisaldehyde–conc. sulphuric acid–methanol (1:1:10, v/v) followed by heating the plate at 100°C for 15 min. The drugs were satisfactorily resolved with R_F values 0.59 ± 0.02 and 0.40 ± 0.02 for dihydroartemisinin and piperaquine phosphate, respectively. Linearity of the method was investigated in the range of 200 – 700 ng/spot for dihydroartemisinin and 100 – 700 ng/spot for piperaquine phosphate. The intra-day and inter-day relative standard deviations for both components were less than 2.0% and the validation parameters were in compliance with ICH guidelines. Hence the method can be utilized for the routine quality control analysis of the above drugs.