Geometric constraints at the surfactant headgroup: effect on lipase activity in cationic reverse micelles.

The primary objective of the present article is to understand how the geometric constraints at the surfactant head affect the lipase activity in the reverse micellar interface. To resolve this issue, surfactants were designed and synthesized, and activity was measured in /water/isooctane/n-hexanol reverse micellar systems at z ([alcohol]/[surfactant])=5.6, pH 6.

Metabolism of metamitron in goat following a single oral administration of a nontoxic dose level: a continued study.

Disposition kinetic behavior and metabolism studies of metamitron and its metabolite in terms of the parent compound were carried out in black Bengal goats after a single oral administration of a nontoxic oral dose at 30 mg kg(-1) of body weight. Metamitron was detected in the blood sample at 5 min (2.23 +/- 0.

Triflupromazine: a microbicide non-antibiotic compound.

The antipsychotic phenothiazine triflupromazine, possessing a methyl-thio substituent at position 10 and a fluorine moiety at position 2, exhibited significant antibacterial activity against 279 strains of Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration (MIC) of the drug, according to the agar dilution method, was between 2 and 50 microg/ml for Staphylococcus aureus, and 5 and 100 microg/ml for shigellae and vibrios. Triflupromazine, when injected intraperitoneally into Swiss albino mice at a concentration of 30 microg/mouse (20 g), manifested a significant protection to the mice (p<0.

Interface effects on mechanical properties of particle-reinforced composites.

Objectives: Effective bonding between the filler and matrix components typically improves the mechanical properties of polymer composites containing inorganic fillers. The aim of this study was to test the hypothesis that composite flexural modulus, flexure strength, and toughness are directly proportional to filler-matrix interfacial shear strength.

Methods: The resin matrix component of the experimental composite consisted of a 60:40 blend of BisGMA:TEGDMA.

Influence of processing-induced phase transformations on the dissolution of theophylline tablets.

The object of this investigation was to evaluate the influence of (1) processing-induced decrease in drug crystallinity and (2) phase transformations during dissolution, on the performance of theophylline tablet formulations. Anhydrous theophylline underwent multiple transformations (anhydrate --> hydrate --> anhydrate) during processing. Although the crystallinity of the anhydrate obtained finally was lower than that of the unprocessed drug, it dissolved at a slower rate.

Modification of pharmacokinetics of cefotaxime in uranyl nitrate-induced renal damage in black bengal goats.

Pharmacokinetics of cefotaxime (50 mg/kg, i.m.) were studied in both healthy and kidney damaged female black Bengal goats.

Use of glancing angle X-ray powder diffractometry to depth-profile phase transformations during dissolution of indomethacin and theophylline tablets.

Purpose: The purpose of this study was (i) to develop glancing angle x-ray powder diffractometry (XRD) as a method for profiling phase transformations as a function of tablet depth; and (ii) to apply this technique to (a) study indomethacin crystallization during dissolution of partially amorphous indomethacin tablets and to (b) profile anhydrate --> hydrate transformations during dissolution of theophylline tablets.

Methods: The intrinsic dissolution rates of indomethacin and theophylline were determined after different pharmaceutical processing steps. Phase transformations during dissolution were evaluated by various techniques.

Liquid chromatography/coordination ion spray-mass spectrometry for the analysis of rubber vulcanization products.

Liquid chromatography/coordination ion spray-mass spectrometry has been used for the identification of reaction products in a model rubber vulcanization process. After LC separation using reversed-phase conditions, AgBF(4) in acetonitrile was added, and strong signals were observed for silica-rubber coupling agents and products of the reaction between these and alkenes. The method performs best for substances containing sulfur chains with chain lengths between two and eight sulfur atoms, but sulfur-free compounds containing triethoxysilyl groups were detected as well.

Toxicokinetics, recovery, and metabolism of metamitron in goat.

Toxicokinetic behavior and metabolism studies of metamitron and its effect on the cytochrome P(450) content of liver microsomal pellet were carried out in black Bengal goats after a single oral administration at 278 mg kg(-1) and consecutive oral administration of 30 mg kg(-1) for 7 days. Metamitron was detected in the blood sample at 0.08 h (12.

Silane treatment effects on glass/resin interfacial shear strengths.

Objective: Methacrylic resin-based dental composites normally use a bifunctional silane coupling agent with an intermediary carbon connecting segment to provide the interfacial phase that holds together the organic polymer matrix with the reinforcing inorganic phase. In this study, fiber pull-out tests were used to measure the interfacial bond strength at the fiber-matrix interface.

Methods: Glass fibers (approximately 30 microm diameter, 8 x 10 (-2)m length, MoSci) were silanated using various concentrations (1, 5 and 10%) of either 3-methacryloxypropyl-trimethoxysilane (MPS) or glycidoxypropyltrimethoxy-silane (GPS) in acetone (99.

Filler-coupling agent-matrix interactions in silica/polymethylmethacrylate composites.

The interactions of the silane coupling agent methacryloxypropyltrimethoxysilane (MPS) with both fumed silica and a polymethylmethacrylate (PMMA) resin matrix were investigated using thermogravimetric analysis and Fourier transform infrared spectroscopy. OX 50 fumed silica was silanated with MPS at concentrations of 1% and 5% in aqueous ethanol (95%), acetone, and anhydrous toluene. Methyl methacrylate was polymerized with the silanated fumed silica (5% wt/wt) to form composites.

Antimicrobial activity of new coumarin derivatives.

A preliminary exploration of coumarin analogs as novel antimicrobial agents was carried out to determine the basic features of the structure responsible for the observed biological activity. The substituents ester or carboxylic acid on the coumarin ring were needed to have potent inhibitory activity against both Gram-positive and Gram-negative bacteria. The presence of phenolic hydroxyl group and/or carboxylic acid was necessary to possess higher activity against Helicobacter pylori.

Stimulation of pregnenolone metabolism and aromatase activity by luteinizing hormone in mouse uterus.

In vitro metabolism of pregnenolone (P5) as well as production of 17beta-estradiol (E2) were studied in uteri of untreated and luteinizing hormone (LH)-treated mice that had been ovariectomized (OVX) at late-diestrus stage. In the uteri of untreated mice, [H]pregnenolone was shown to be metabolized to Delta-components such as 17alpha-hydroxypregnenolone (17alpha-P5) and dehydroepiandrosterone (DHEA), whereas LH treatment resulted in significant increases in the formation of progesterone (P4), 17alpha-hydroxyprogesterone (17alpha-P4), androstenedione (AD) and testosterone (T). This was assessed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC).

Trabeculectomy versus trabeculotomy in congenital glaucoma.

Congenital glaucoma is one of the main causes of blindness in children and is more common in Saudi Arabia than in Western countries, perhaps owing to the prevalence of consanguinity with families. Trabeculotomy has given poorer in Saudi Arabia than elsewhere. This study compared the results of trabeculotomy (67% success rate) with trabeculectomy (54% success rate), and reports fewer complications following trabeculotomy.

Ocular side effects of systemic steroid therapy in renal transplant patients.

Sixty-one renal transplant patients were studied for ocular complications of steroid therapy. Twenty patients (32.8%) were found to have posterior subcapsular cataract.

Concentration of clobetasone butyrate in aqueous humour.

The concentrations of clobetasone butyrate and betamethasone were measured in aqueous humour of patients undergoing cataract extraction 12.5 to 18.5 hours after application into the lower conjunctival sac of an ointment containing 0.