NO synthase (NOS) enzymes convert L-arginine to NO in two sequential reactions whose rates (k(cat1) and k(cat2)) are both limited by the rate of ferric heme reduction (k(r)). An enzyme ferric heme-NO complex forms as an immediate product complex and then undergoes either dissociation (at a rate that we denote as k(d)) to release NO in a productive manner, or reduction (k(r)) to form a ferrous h...

Various methods are available to formulate water soluble drugs into sustained release dosage forms by retarding the dissolution rate. One of the methods used to control drug release and thereby prolong therapeutic activity is to use hydrophilic and lipophilic polymers. In this study, the effects of various polymers such as hydroxypropyl methylcellulose (HPMC), ethylcellulose (EC) and sodium car...

A novel methanol derived graphene (MDG) and gentamicin sulfate nanohybrid was prepared, and the loading and release behaviour of gentamicin on MDG is investigated. An efficient drug loading of 2.57 mg mg(-1) was obtained at pH 7. By applying release kinetic models, the mechanism of release of the drug from the MDG matrix was found to be following the Korsmeyer-Peppas model. However, the diffusi...

Neurotransmitter release is triggered by calcium ions and depends critically on the correct function of three types of SNARE [soluble N-ethylmaleimide-sensitive factor attachment protein (SNAP) receptor] proteins. With use of the large calyx of Held presynaptic terminal from rats, we found that cleavage of different SNARE proteins by clostridial neurotoxins caused distinct kinetic changes in ne...

An oral sustained-release floating tablet formulation of metformin HCl was designed and developed. Effervescence and swelling properties were attributed on the developed tablets by sodium bicarbonate and HPMC-PEO polymer combination, respectively. Tablet composition was optimized by response surface methodology (RSM). Seventeen (17) trial formulations were analyzed according to Box-Behnken desi...

Heavy metals release from contaminated sediments is one of the most important chemical processes affecting overlying water quality in river, lake, and ocean. The objective this study was to determine leaching properties, kinetic rate, amount zinc (Zn) cadmium (Cd) river sediment by gold mining. Speciation Zn Cd extracted a modified BCR extraction procedure. Release kinetics were studied simulat...

1Department of Health, Campus Teresina Central, Federal Institute of Education, Science and Technology of Piauí, Teresina, PI, Brazil, 2Department of Pharmacy, State University of Paraíba, Campina Grande, PB, Brazil, 3College of Pharmacy, Campus Minister Petronio Portela, Federal University of Piauí, Teresina, PI, Brazil, 4Laboratory of Experimental Neurochemistry Research, Federal University o...