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Biomedical subjects

A Hussain

Publications and source records attributed to A Hussain.

At least 199 records · Page 11Linked to original sources
PubMed1984

Review on correlation between pharmacologic response and drug disposition.

It is generally accepted that there is some type of correlation between the amount of drug in the body, or the concentration at the target site, and the pharmacologic or clinical response. This assumption becomes even more important with the increasing use of blood level measurement in monitoring of drug therapy. Whereas much information is available on the pharmacokinetics of drugs, few studies are concerned with the establishment of a correlation between disposition and response. The purpose of this review is to summarize the attempts made in this regard. Only those drugs for which a pharmacokinetic-pharmacodynamic relationship can be demonstrated are candidates for optimization of drug therapy through drug level monitoring and pharmacokinetic dosage regimen design.

Animals↗
PubMed1981

First-pass metabolism of ethinyl estradiol in dogs and rats.

The contraceptive steroid ethinyl estradiol was extensively metabolized when given orally in solution to dogs. It was thought at first that metabolism occurred exclusively in the liver. However, use of standard equations to predict the oral bioavailability of drugs known to be metabolized by hepatic first pass resulted in significantly higher values than those obtained experimentally. To rationalize the data and to determine whether ethinyl estradiol also is metabolized in the gut wall during absorption, metabolism in rats was studied. The drug was administered in solution intraduodenally, intraportally, and intravenously as a bolus by first-order infusion. The results indicate that, in rats, 40% of the drug is metabolized by the gut wall and 79% of the drug in the portal blood is metabolized by the liver intraduodenal administration.

Animals↗
PubMed1981

Effect of complex formation between 4-hexylresorcinol and ethyl myristate on release rate of 4-hexylresorcinol from petrolatum base.

The effect of ethyl myristate on the release rate of 4-hexylresorcinol from petrolatum base was studied at pH 7.4 and 37 degrees. 4-Hexylresorcinol was analyzed spectrophotometrically at 278 nm. The release rate of hexylresorcinol from the ointments was directly proportional to the square root of time and depended on the percentage of ethyl myristate in the ointment base. For 0, 0.5, 1, 3, and 5% of ethyl myristate, the release rates were 29.6, 35.4, 38.3, 55.7, and 70.0 micrograms/hr1/2/cm2, respectively. The solubility of hexylresorcinol in the petrolatum base was determined as a function of ethyl myristate using partitioning techniques. The enhancement in hexylresorcinol solubility was rationalized on the basis of 1:1 and 1:2 complexes between hexylresorcinol and ethyl myristate. The complexation constants of these complexes were estimated to be 10 M-1 and 206.1 M-2, respectively. The diffusion coefficient of hexylresorcinol in the petrolatum base was estimated to be 1.31 x 10(-8) cm2/sec.

Hexylresorcinol↗
PubMed1981

Solubility behavior of phenolic compounds in hexane-ethyl acetate, hexane-ethyl myristate, and hexane-ethyl pivalate cosolvent systems.

Interactions of phenolic compounds 4-hexylresorcinol and 3,4-dimethylphenol with esters were studied using hexane-ester cosolvent systems by both phase solubility and partitioning methods. The data obtained by the phase solubility method were variable and could not be analyzed by any mathematical model. The data obtained by the partitioning method, however, strongly suggest that 4-hexylresorcinol forms 1:1 and 1:2 complexes with the esters in hexane, while 3,4-dimethylphenol forms only 1:1 complexes with the same esters.

Acetates↗
PubMed1981

Blastogenic response of swine lymphocytes in whole blood, purified blood, spleen cell, and lymph node cell cultures with concanavalin A and phytohemagglutinin.

Microcultures of swine whole blood, purified blood lymphocytes (PBL), spleen cells, and lymph node (LN) cells were tested for stimulation by concanavalin A (conA) and phytohemagglutinin (PHA). A cell concentration of 2 x 10(6)/ml and a 1:20 dilution of whole blood were needed for optimal stimulation of conA and PHA. Optimal stimulation of whole blood lymphocytes (WBL) and LN cells was obtained by 20 micrograms of conA/ml, but 10 micrograms/ml of this mitogen was adequate for spleen cells. The PBL and LN cells were optimally stimulated by 20 microliters of PHA/ml, but 80 microliters and 40 microliters/ml of this mitogen were required for stimulating the whole blood and spleen cells, respectively. Four days' incubation was needed for maximal blastogenesis of WBL with conA. This could be achieved after 3 days' incubation with PBL and spleen and LN cells. Whole blood and spleen cells were stimulated by PHA after 3 days' incubation, but PBL and LN cells required 4 days' incubation. Reproducibility, sensitivity, and comparison of various cultures were discussed.

Animals↗
PubMed1980

Nasal absorption of propranolol from different dosage forms by rats and dogs.

The blood levels of propranolol in rats and dogs were compared after the administration of nasal, intravenous, and oral solutions. The results indicate that the blood drug levels after nasal and intravenous administration were identical, but the oral administration resulted in considerably lower blood levels. Sustained-release formulations of the drug also were administered nasally and resulted in low initial but prolonged blood levels. The bioavailability of the sustained-release formulation was identical to that of the intravenous administration.

Absorption↗
PubMed1979

Effect of hydroxyl group substituents on pyran ring on hydrolysis rate of benzoates: 2-tetrahydropyranyl benzoate.

The hydrolysis of 2-tetrahydropyranyl benzoate was followed spectrophotometrically at 240 nm and was first order with respect to the compound, independent of pH, and very sensitivie to solvent polarity and had an isotope effect (kD2O/kH2O) near unity. The pH-independent hydrolysis rate was about 1 X 10(6) times faster than that of the corresponding glucosly benzoate. The results suggest that the presence of hydroxyl groups on the pyran ring has tremendous effect on the hydrolysis rate of these compounds.

Benzoates↗