Ladan Tayebi - Academia.edu (original) (raw)

Uploads

Papers by Ladan Tayebi

Turkish Journal of Pharmaceutical Sciences, 2010

Pharmacokinetic parameters of sildenafil in Iranian volunteers were determined by using a simple,... more Pharmacokinetic parameters of sildenafil in Iranian volunteers were determined by using a simple, rapid and sensitive HPLC-UV method. The assay procedure involves extraction of sildenafil in basic pH with dichloromethane. After evaporation of dichloromethane under a steam of nitrogen; the residue was dissolved in 0.2 mL of mobile phase. The mobile phase consists of acetonitrile - KH2P04 (30 mM) (56:44, v/v). The column was RPC18 and flow rate was 1.0 mL/min. at ambient temperature (25°C). Peaks were monitored by UV detector set at 290 nm. Chlordiazepoxide was used as internal standard (IS). The peak areas of sildenafil/lS ratio versus drug concentrations relationship was linear (r>0.992). The extraction efficiency was 92%. The minimum quantifiable concentration was found to be 10 ng/mL. The method was used to determination of plasma concentrations. 2x50 mg of Viagra tablets were administered toll healthy male volunteers and sildenafil was determined in the plasma and pharmacokine...

Isosorbide dinitrate (ISDN) is an effective drug in treatment of angina pectoris. In this study a... more Isosorbide dinitrate (ISDN) is an effective drug in treatment of angina pectoris. In this study a new generation of electron capture detector (non-radioactive) with a short, non-polar and wide-bore column was used for analysis of ISDN in human serum. ISDN was extracted from serum by a mixture of ether and ethyl acetate and concentrated at room temperature. The method was linear between 5-50 ng/mL. Recovery and accuracy were 99-108% and greater than 90%, respectively, and inter-day precision was lower than 13%. Pharmacokinetic parameters were analyzed after oral administrations of Isocor 40 mg sustained release tablet in comparison with Isoket Retard 40. The statistical results obtained from comparison of C max , T max and AUC were reported to be bioequivalent. Further more, the method used was found to be sensitive and accurate in pharmacokinetic studies.

Pharmacokinetic parameters of sildenafll in Iranian volunteers were determined by using a simple,... more Pharmacokinetic parameters of sildenafll in Iranian volunteers were determined by using a simple, rapid and sensitive HPLC-UV method. The assay procedure involves extraction of sildenafll in basic pH with dichloromethane. After evaporation of dichloromethane under a steam of nitrogen; the residue was dissolved in 0.2 ml of mobile phase. The mobile phase consists of acetonitrile - KH2P04 (30 mM) (56:44, v/v). The column was RPC18 and flow rate was 1.0 mL/min. at ambient temperature (25°C). Peaks were monitored by UV detector set at 290 nm. Chlordiazepoxide was used as internal standard (IS). The peak areas of sildenafil/IS ratio versus drug concentrations relationship was linear (r>0.992). The extraction efficiency was 92%. The minimum quantifiable concentration was found to be 10 ng/mL. The method was used to determination of plasma concentrations. 2x50 mg of Viagra tablets were administered toll healthy male volunteers and sildenafll was determined in the plasma and pharmacokine...

Journal of pharmaceutical and biomedical analysis

We report a novel method for the simultaneous determination of omeprazole and their main metaboli... more We report a novel method for the simultaneous determination of omeprazole and their main metabolites (omeprazole sulphide, omeprazole sulphone and 5-hydroxy omeprazole) in human urine samples. For this purpose, two new capillary electrophoresis (CE) methods were developed for the simultaneous determination of target compounds, using initially diode-array for optical detection and electrospray ionization-mass spectrometry (ESI-MS) for metabolites identification and identity confirmation. A new metabolite (5-hydroxysulphide omeprazole) was identified by electrospray ionization multi-stage mass spectrometry (ESI-MS2) fragment which was then used to support the proposed chemical structure. Pharmacokinetic results using CE method were compared with those obtained when a HPLC method was used. Equivalent pharmacokinetics profiles resulted when any analytical methods were carried out.