High performance thin layer chromatographic determination of nifedipine in human serum after liquid-liquid extraction

a method using hptlc for quantitation of nifedipine in serum was developed and validated. it includes a liquid-liquid extraction, and carbamazepine as internal standard. chloroform: ethyl acetate: cyclohexane (19:2:2, v/v/v) was the mobile phase. the method showed good relationship (r = 0.996) (2.00 to 25.00 ng/band, corresponding to 0.02 and 0.25 ng/μl in serum). the % rsd of intra-assay and inter-assay, were between 0.57 and 3.56 and 1.16 to 3.60, respectively. lod and loq were 0.72 and 0.86 ng/band, respectively. the recovery values were between 93 and 102%. rf for nifedipine and carbamazepine were 0.31 and 0.10, respectively.