Hanaa Saleh

Colorimetric determination of β-blockers in pharmaceutical formulations

Abstract A simple, accurate, precise and sensitive colorimetric method for the determination of some β-blockers as atenolol (Ateno), metoprolol (Metop), sotalol (Sot) and nadolol (Nad) is described. This method is based on the formation of charge transfer complex with 4-chloro-7-nitro-2,1,3-benzoxadiazole (NBD–Cl) in methanolic–aqueous (for Ateno and Metop) or acetone–aqueous (for Sot and Nad) medium [30% (v/v)]. The orange color products are measured at 485, 470, 465 and 462 nm for Ateno, Metop, Sot and Nad, respectively. The optimization of various experimental conditions is described. Beers law is obeyed in the range 0.4–60 μg ml−1 while that obtained applying Ringbom is 0.8–56 μg ml−1. The molar absorptivity, Sandell sensitivity, detection and quantification limits are calculated. The results obtained showed good recoveries of 99.5±1.1, 100.3±1.2, 100.5±1.0 and 99.3±1.1% with relative standard deviations of 0.74, 0.98, 1.15 and 0.87% for Ateno, Metop, Sot and Nad, respectively. Applications of the proposed method to representative pharmaceutical formulations are successfully presented.

Quantitative HPLC analysis of mebeverine, mesalazine, sulphasalazine and dispersible aspirin stored in a Venalink monitored dosage system with co-prescribed medicines.

An HPLC method for the quantitative analysis of mebeverine HCl, 5-aminosalicylic acid (5-ASA), sulphasalazine and dispersible aspirin has been developed and then applied to these specific medicines when stored, with other medications, in Venalink blister packs (monitored dosage system) for periods of up to 35 days. Chromatographic separation was achieved on a reversed-phase C(12) column with an isocratic mixture of methanol, water and acetic acid as the mobile phase. The method was validated regarding: accuracy, precision, detection limits, quantification limits, specificity and robustness.

DEVELOPMENT AND VALIDATION OF RAPID STABILITY INDICATING HPLC-DETERMINATIONS OF ANTIEPILEPTIC DRUGS PHENOBARBITAL IN SUPPOSITORIES AND PHENYTOIN IN CAPSULES AS WELL AS IN URINE SAMPLE

Two simple, rapid, accurate, and stability indicating HPLC methods are described for quantitation of Phenobarbital and Phenytoin in bulk powders, dosage forms, or urine. Chromatographic quantitation of Phenobarbital was developed on Chromolith® Performance RP-18e column, using isocratic binary mobile phase of MeOH and H2O (38: 62, V/V) at flow rate of 3 mLmin−1. Determination of Phenytoin was achieved using a conventional RP C-18, applying isocratic binary mobile phase of ACN and H2O (25: 75, V/V) at flow rate of 1 mL min−1. The elution times of Phenobarbital and Phenytoin are 1.397 ± 0.039 and 5.604 ± 0.013 min, respectively. Each method was validated for system suitability, linearity, precision, limits of detection and quantitation, specificity, stability, and robustness. Stability tests were done through exposure of the analyte solutions to four different stress conditions: reflux with 1 N HCl, reflux with 1 N NaOH, reflux with 30% H2O2, and exposure to UV radiation. Limits of detection and quantitation were 0.125 and 0.250 µgmL−1 as well as 0.250 and 0.500 µgmL−1 for Phenobarbital and Phenytoin, respectively. Due to the short separation time of Phenobarbital, the method was applied for dissolution study in presence of beta-cyclodextrin. The proposed methods can be used for routine samples or stability studies.

Performance Comparison Between Monolithic, Core-Shell, and Totally Porous Particulate Columns for Application in Greener and Faster Chromatography

Background: The introduction of monolithic rods and core-shell particles as new morphologies of packing materials different from the conventional totally porous particles resulted in a leap forward for performance in LC. Meanwhile, environmental safety has become increasingly important in many areas, especially in industry and research laboratories. Objective: This study compared the efficiencies of commercially available columns of different lengths and diameters when greener chromatographic conditions were utilized. The main purpose of this study is to help practitioners select the most appropriate stationary phase for faster and greener analysis. Methods: The three types of stationary phases were compared in terms of separation efficiency, number of theoretical plates, peak shape, selectivity, resolution, analysis time, mobile phase consideration, and permeability using six drug molecules. Results: Results indicated that core-shell and monolithic stationary phases had superiority over the conventional totally porous particles in terms of efficiency and speed of analysis. Monolithic rods had lower column backpressure and higher permeability, so they are more suitable for higher mobile phase flow rates and viscosities. However, core-shell particles provided enhanced peak shapes and number of theoretical plates. Conclusions: The choice will depend on the main purpose of analysis and the composition of the mobile phase. Compromise must be made to obtain the best trade-off between separation efficiency and analysis speed. Highlights: This study is the first to consider green chromatography concepts for the selection of the best stationary phase of new morphologies.

Validated, Ultra High Efficiency RP-HPLC and Stability Indicating Method for Determination of Tranylcypromines Sulphate in Bulk and in Tablet Dosage Forms

at 30 ° C, using simple isocratic mobile phase of acetonitrile - orthophosphoric acid 0.1 % (10: 90, v/v). The flow rate was 1.0 mL/min and the detection was performed at 220 nm. The retention time of the drug was 2 min while for the reported method was 6.7 min. The method was validated according to International Conference on Harmonization (ICH) guidelines. Tranylcypromine was subjected to the stress conditions of hydrolytic acidic, basic, oxidative, and photolytic degradation. The assay was linear over the concentration range of 3-150 µg mL -1 and the correlation coefficient was 1. The RSD% of inter and intraday precision was less than 1 %. The % recoveries were found to be 100.58 % proved that the proposed method is sufficiently accurate and precise. The method distinctly separates the drug from its degradation products within 2 min and total run time of 8 min.