Extraction and determination of cyproheptadine in human urine by DLLME-HPLC method

Novel dispersive liquid-liquid microextraction [DLLME], coupled with high performance liquid chromatography with photodiode array detection [HPLC-DAD] has been applied for the extraction and determination of cyproheptadine [CPH], an antihistamine, in human urine samples. In this method, 0.6 mL of acetonitrile [disperser solvent] containing 30 micro L of carbon tetrachloride [extraction solvent] was rapidly injected by a syringe into 5 mL urine sample. After centrifugation, the sedimented phase containing enriched analyte was dissolved in acetonitrile and an aliquot of this solution injected into the HPLC system for analysis. Development of DLLME procedure includes optimization of some important parameters such as kind and volume of extraction and disperser solvent, pH and salt addition. The proposed method has good linearity in the range of 0.02-4.5 micro g mL[-1] and low detection limit [13.1 ng mL[-1]]. The repeatability of the method, expressed as relative standard deviation was 4.9% [n = 3]. This method has also been applied to the analysis of real urine samples with satisfactory relative recoveries in the range of 91.6-101.0%

rapid, simple, liquid chromatographic-electrospray ionization, ion trap mass spectrometry method for the determination of finasteride in human plasma and its application to pharmacokinetic study

A fast, accurate, sensitive, selective and reliable method using reversed-phase high performance liquid chromatography coupled to electrospray ionization ion trap mass spectrometry was developed and validated for the determination of finasteride in human plasma. After protein precipitation with perchloric acid, satisfactory separation was achieved on a Zorbax Eclipse[registered] C[8] analytical column using a mobile phase consisted of acetonitrile, 2 mM ammonium formate buffer [58:42, pH adjusted at 2.5 using formic acid]; the flow rate was 0.25 mLmin[-1] and the column oven was set to 50°C. Tamoxifen citrate was used as internal standard. This method involved the use of [M + H][+] ions of ?nasteride and IS at m/z 373 and 372 respectively with the selected ion monitoring [SIM] mode. The calibration curve was linear over the range of 0.1-60 ng mL[-1]. The limit of quantification for finasteride in plasma was 0.1 ng mL[-1]. The intra-day and inter-day repeatability [precision] were 2.68-13.87% and 2.14-14.69% respectively. Intra-day and inter-day accuracy were 98-101.57% and 99.7-110%. The assay method has been successfully used to estimate the pharmacokinetics of finasteride after oral administration of a 5 mg tablet of finasteride in 12 healthy volunteers