Development and validation of a stability-indicating HPTLC method ...

Dinesh Kumar Jain et al., Int J Pharm Biomed Sci 2011, 2(2), 55-6059Table 3Assay result of marketed formulationS. No. Actual concentration (mg) Concentration found (mg) % ContentLOR PCM LOR PCM LOR PCM1 300 400 302.43±4.22 400.31±1.64 101.02±1.34 100.08±1.92Table 4Forced degradation studiesSample exposure conditions LOR PCMNumber of degradation products % Recovery (n=3) Number of degradation products % Recovery (n=3)(R f value)(R f value)1 M HCl,8h, RT 3 (0.28,0.72, 0.88) 89.23 ±2.17 2 (0.75,0.88) 96.02 ±3.541 M NaOH, 8h, RT 4 (0.01,0.04, 0.72,0.88) 79.0 ±2.94 1(0.4) 76.05 ±1.3710%,H 2 O 2 , 8h, RT 2 (0.71,0.87) 74.34 ±7.15 2(0.40,0.64) 75.14 ±0.82Sunlight, 8h 1(0.76) 45.2 ±1.91 1 (0.79) 13.53 ±1.31Heat, 3h, 55°C 2 (0.31,0.75) 99.67 ±2.43 2 (0.76,0.96) 93.75 ±0.84a) b)Fig.4. HPTLC chromatogram obtained from forced degradation studies (a) acid degradation (1 M HCl, 8h, RT) showing 3 degradants at R f values 0.28, 0.72,0.88 for LOR and 2 degradants at R f values 0.75, 0.88 for PCM and (b) base degradation (1 M NaOH, 8h, RT) showing 4 degradants at R f values 0.01, 0.04,0.72, 0.88 for LOR and 1 degradant at R f value 0.4 for PCMseparation was obtained at 290 nm (Fig.2). The systemsuitability test parameters are shown in Table 1.In the development of HPTLC method, the mixture ofchloroform:methanol:ethyl acetate:ammonia (20:15:55:10, %v/v/v/v) was selected as a mobile phase as it could resolveLOR and PCM spots with a better peak shape and offered anoptimum separation at R f 0.23 ± 0.01 and 0.60 ± 0.02 (n=6)for LOR and PCM respectively (Fig.3a).Linear correlation was obtained in the range of 2-10μg/mL and 5-100 μg/mL for the HPLC method and 300-550ng/band and 100-500 ng/band for HPTLC method for LORand PCM, respectively. The average linear regressionequation was represented as Y = 10.348X + 1226.7 for LOR,and Y = 4.665X + 137.04 for PCM, where X is theconcentration of drug and Y is the peak area. The overlayspectra of LOR, PCM are shown in Fig.3b. The repeatabilityof the method was checked by spotting 4 μL of a combinedstandard solution six times on the plate (n= 6); the RSD forthe peak area was found to be 0.72 and 1.2 for LOR andPCM using HPLC and 1.24 and 1.02 for LOR and PCM forHPTLC. The intra-day and inter-day The RSD values werefound to be