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Biomedical subjects

F A Mohamed

Publications and source records attributed to F A Mohamed.

At least 19 recordsLinked to original sources
PubMed2002

Differential scanning calorimetry to investigate the compatibility of ciprofloxacin hydrochloride with excipients.

The compatibility between ciprofloxacin hydrochloride (CFX) and some excipients was evaluated using differential scanning calorimetry (DSC). Physical mixture, coground mixture, compressed mixture and kneaded mixture were prepared to study the effect of sample manipulation. In addition, the samples of physical mixture were also accelerated at 55 degrees C for three weeks to obtain more reliable conclusions. Different types of excipients currently used in tablet or capsule formulations namely, calcium phosphate dibasic dihydrate (Emcompress), magnesium stearate lactose, sorbitol, mannitol, croscarmellose sodium (Ac-Di-Sol), sodium carboxymethyl starch (Primojel), microcrystalline cellulose (Avicel PH 101, Emcocil) were examined. The DSC scan of CFX displayed two endothermic peaks probably as a result of a fusion process followed by a decomposition process. CFX appeared to interact with sorbitol, mannitol, Ac-Di-Sol, Primojel, Avicel PH 101 and Emcocil.

Anti-Infective Agents↗
PubMed1991

Effects of some trace elements on platelet function in rats.

The present study portrays the effects of some elements, namely: iron, zinc, copper, magnesium and gold, on platelet count, PCV and platelet aggregation, 60 minutes following administration of the metal salts. Marked thrombocytopenia was encountered in rats treated with ferrous sulphate while the platelet count was significantly changed with the other elements tested. The PCV was significantly increased following treatment with ferrous sulphate and large dose of gold chloride, but was insignificantly altered with the other elements. As regards platelet aggregation, all metals tested, with the exception of magnesium caused significant inhibition of platelet aggregation was only significantly impaired following treatment with iron and gold, but was insignificantly altered following treatment with zinc and copper. On the other hand, treatment with magnesium resulted in enhancement of both ADP- and collagen-induced aggregation. The mechanisms underlying these effects are discussed.

Animals↗
PubMed1991

In vitro effects of trace elements on blood clotting and platelet function. A--Iron, copper, and gold.

The present in vitro study of the effects of iron on the blood coagulation mechanism in rats showed that addition of ferrous sulphate to pooled rat plasma resulted in inhibition of blood coagulation, as shown by prolongation of the clotting parameters tested, an effect which was dose-dependent. In vitro addition of ferrous sulphate to rat PRP in doses of 2-5 mg/ml significantly decreased platelet aggregation in response to ADP, while collagen-induced aggregation was significantly diminished in presence of the higher doses of ferrous sulphate (4-5 mg/ml). Also, preincubation of ferrous sulphate with thrombin or with pure fibrinogen indicated that iron could produce decrease of thrombin activity as well as impairment of fibrinogen clottability. In vitro addition of copper sulphate (300-1000 micrograms/ml) elicited an anticoagulant effect, though thrombin time was markedly shortened with all tested concentrations of copper sulphate. Addition of copper sulphate to PRP produced inhibition of platelet aggregation in response to PRP produced inhibition of platelet aggregation in response to ADP and to collagen. Preincubation of copper sulphate with thrombin resulted in slight enhancement of thrombin activity followed by inhibition, while preincubation of copper sulphate with pure fibrinogen caused only minimal impairment of fibrinogen clottability. Also, addition of gold chloride in doses of 50-500 micrograms/ml to plasma in vitro produced a dose-dependent progressive prolongation of all clotting parameters tested, the effects reaching a maximum after 30 min. incubation. Further the in vitro addition of gold chloride to rat PRP resulted in marked inhibition of platelet aggregation in response to both ADP and collagen. In addition, preincubation of gold chloride with thrombin or with pure fibrinogen showed that gold exerted an antithrombin action and prolonged the fibrinogen clotting time indicating impaired fibrinogen clottability.

Animals↗
PubMed1988

Short communication.

A simple and rapid calorimetric method for the determination of 10 sulphonamides as single entities and sulphamethoxazole in combination with trimethoprim without prior separation was developed. The method is based on the reaction of sulphonamide with phenothiazine and N-bromosuccinimide at pH 6 to produce a blue coloured product after acidification. The chromogen for all the sulphonamides was measured at 605 nm. The effect of several variables on colour development (concentration of phenothiazine and N-bromosuccinimide, time, pH) were established. Beer's Law was obeyed for all the drugs. The method was successfully applied to the analysis of single component sulphonamide tablets and ophthalmic solutions, with average results of labelled claim of 96.7 +/- 0.95 to 100.67 +/- 1.2. A good correlation was observed between molar absorptivities and pK(a) values of the sulphonamides (r = 0.9005).

Journal Article↗
PubMedDate not supplied

Fibrinolytic activity in haemophiliacs.

The fibrinolytic activity was studied in 7 haemophiliacs, in comparison with 5 normals and 7 patients with disseminated intravascular coagulopathy, by determining the level of the fibrin(ogen) degradation products (FDP) in samples obtained as sera, clotting occurring naturally, and samples obtained as plasma and converted into serum by addition of thrombin-EACA. It was found that in haemophiliacs serum samples had normal FDP levels while plasma converted to serum showed high levels. This was explained by the fibrinolytic action of thrombin. Fibrinolysis was not prevented by EACA present due to the fact that it is an inhibitor of the plasminogen system but not of thrombin.

Adolescent↗
PubMedDate not supplied

Spectrophotometric determination of some catecholamine drugs using metaperiodate.

A rapid spectrophotometric procedure for the determination of isoprenaline salts, levodopa, dopamine hydrochloride, and dobutamine hydrochloride, either in the drug substances or in pharmaceutical formulations, is described. The method is based on the development of orange, red, or violet products with sodium metaperiodate in an aqueous alcoholic medium. The reaction is suggested to proceed via oxidative cyclization of the catecholamine to form an aminochrome. The wavelengths of maximum absorption range from 465 to 520 nm. The structure of the cyclization product was confirmed by ultraviolet, infrared, and nuclear magnetic resonance spectroscopy and microanalysis data.

Catecholamines↗
PubMedDate not supplied

Colorimetric determination of certain phenothiazine drugs by using morpholine and iodine-potassium iodide reagents.

A colorimetric method was developed for the quantitative estimation of 11 phenothiazine drugs. The method is based on the interaction of unsulfoxidized drug with morpholine and iodine-potassium iodide reagents. The interaction for all studied phenothiazine drugs yields a blue product with 2 absorption maxima: one in the range of 620-640 nm with lower molar absorptivity and the other in the range of 662-690 nm with higher molar absorptivity. The color was stable for at least 10 h. The reproducibility and recovery of the method were excellent. The method was applied successfully to the analysis of various commercially available phenothiazines in different dosage forms. The results were comparable to those obtained by official procedures. The suitability of the method for detection and estimation of promethazine excreted in urine has been suggested by preliminary experiments. Reaction products have been isolated and identified.

Antipsychotic Agents↗