Browsing by Author "Abdallah O.M."

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Determination of metoprolol and felodipine in binary mixture using chemometric-assisted spectrophotometric and high-performance liquid chromatographic-UV methods
(Science Publications, 2007) Salem H.; Abdallah O.M.; Analytical Chemistry Department; Faculty of Pharmacy; Minia University; Minia; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; Al-Azhar University; Cairo; Egypt; Analytical Chemistry Department; Faculty of Pharmacy; MSA University; Cairo; Egypt
Four methods were developed for simultaneous determination of metoprolol and felodipine without previous separation. In the first method both drugs were determined using first derivative UV spectrophotometry, with zero crossing measurement at 222 and 235 nm for metoprolol and felodipine, respectively. The second method depends on first derivative of the ratios spectra by measurements of the amplitudes at 250.1 nm for metoprolol and 224.3 nm for felodipine. Calibration graphs are established in the range of 20-150 ?g/ml and 10-60 ?g/ml for metoprolol and felodipine, respectively. The third method describes the use of multivariate spectrophotometric calibration for the simultaneous determination of the analyzed binary mixture where the resolution is accomplished by using partial least squares (PLS) regression analysis. Although the components show high degree of spectral overlap, they are simultaneously determined with high accuracy and without interference of pharmaceutical dosage form excipients. A comparison with the related multivariate method of classicial least squares (CLS) analysis is done showing less relative results due to severe spectral overlap of the studied drugs. In the fourth method (HPLC), a reversed-phase column and a mobile phase of methanol:water:acetonitrile (70:22:8 v/v/v/) at 0.9 ml/ min flow rate is used to separate both drugs and UV detection at 260 nm. Good linearities are obtained in concentration range of 0.15-15 ?g/ml for metoprolol and 0.03-5 ?g/ml for felodipine. All the proposed methods are extensively validated. They have the advantage of being economic and time saving. All the described methods can be readily utilized for the analysis of pharmaceutical formulations, the fourth method (HPLC) is successfully applied for the analysis of both drugs in human serum samples. The results obtained by adopting the proposed methods are statistically analyzed and compared with those obtained by reported methods. � 2007 Science Publications.
RP-HPLC determination of three anti-hyperlipidemic drugs in spiked human plasma and in dosage forms
(Hindawi Limited, 2011) Abdallah O.M.; Analytical Chemistry Department; Faculty of Pharmacy October; University for Modern Sciences and Arts (MSA); El- Wahat Road; Egypt
Sensitive, simple and accurate high performance liquid chromatographic (HPLC) methods for the determination of atorvastatin (AT), fluvastatin (FL) and pravastatin (PV) have been developed. The proposed methods involve the use of a 150 mmx4.6 mm Zorbax Extend-C18 column (5 ?m particle size) and different chromatographic conditions for the separation of the three statins. Linearity range was 5-40, 5-30 and 10-60 ?g mL-1 for AT, FL and PV respectively. The developed methods proved to be successful in the determination of all studied drugs in spiked human plasma samples.