Magda M. El-Henawee

Determination of certain antihistamines through ternary complex formation

Abstract Antihistamines, namely terfenadine and chlorphenoxamine hydrochloride, react with cobalt and toxiocyanate ions to give ternary complexes. These complexes are readily extractable in benzene to give a blue colour with maximum absorption at 625nm. which can be used for Quantitative spectrophotometric analysis. The mean recoveries for authentic samples of terfenadine and chlorphenoxamine hydrochloride were 99.9 ± 0.3 S.E. and 99.9 ± 0.3 respectively (P = 0.05). Alternatively, determination of cobalt content of the benzene extract via atomic absorption spectroscopy provides an indirect method for the determination of these antihistamines. The mean recoveries were 99.33 ± 0.3 and 99.19 ± 0.3 respectively. Both methods were applied to the analysis of pharmaceutical preparations, the results obtained agreed well with those obtained by official methods.

COMPARISON BETWEEN CALIXARENE AND CONVENTIONAL HPLC-STATIONARY PHASES CONCERNING WITH SEPARATION OF ANTIHYPERTENSIVE DRUGS

In this article, the effect of changes in different process variables such as pH, buffer type and concentration, column temperature, injection volume, as well as type and contents of organic modifier on retention behavior of seven antihypertensive drugs from two different categories (Angiotensin II receptor blockers and Diuretics) was investigated. Conventional RP-C18 column (Intersil® ODS-3) and calixarene column (Caltrex BIII®) were used as stationary phases. Calixarene-based stationary phases differ from the conventional RP-C18 in that they are as cyclodextrins in having cavities. The results showed that the examined conditions had different effects on the analytes retention on both columns, for example the elution order had changed and resolution between different analytes took variable behaviors. This can be attributed to the different chemical structures of both stationary phases used. The obtained results indicate that the used stationary phases behave as reversed phases packing and the hydrophobic interaction is main factor having a role in the retention of antihypertensive drugs. The chemical structure and properties of the analytes were found to have an effective role in their separation.

Colorimetric method for the simultaneous determination of chlorphenoxamine hydrochloride and anhydrous caffeine in pure and dosage forms with rose bengal

A rapid, simple and sensitive colorimetric method for the simultaneous determination of chlorphenoxamine HCl and anhydrous caffeine was developed, based on charge-transfer complex formation of the drugs with rose bengal in basic media of pH 9.0. The chlorphenoxamine HCl (I) complex was measured at 588 nm whereas anhydrous caffeine (II) was measured at 551 nm. The optimal experimental parameters for colour production were studied. Beers law was obeyed in the concentration ranges 2–40 and 2–34 μg ml−1 for I and II, respectively. The Ringbom optimum concentration ranges were 3–36 and 3–30 μg ml−1 for I and II, respectively. The results obtained showed good recoveries of 100.2 ± 1.5 and 99.7 ± 1.3% with relative standard deviations of 0.37 and 0.47% for I and II, respectively. Applications of the method to representative pharmaceutical dosage forms are presented and the validity assessed by applying the standard addition technique.

U. V. Derivative Spectrophotometric Determination of Chlorphenoxamine Hydrochloride in Combination with Unhydrous Caffeine

Abstract A rapid spectrophotometric method for the analysis of chlorphenoxamine hydrochloride in combination with unhydrous caffeine was described. The method is based on the determination of chlorphenoxamine hydrochloride by at 225 and 232 nm while unhydrous caffeine recorde zero at the same wave lengths. Unhydrous caffeine determined by at 256 and 283 nm which corresponding to zero reading for chlorphenoxamine hydrochloride.

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.