There is considerable interest in the mechanisms that drive and control the spread of morphogens in developing animals. Although much attention is given to events occurring after release from expressing cells, release itself could be an important modulator of range. Indeed, a dedicated protein, Dispatched, is needed to release Hedgehog from the surface of expressing cells. We find that, in Dros...

Hearing requires the hair cell synapse to maintain notable temporal fidelity (< or =1 ms) while sustaining neurotransmitter release for prolonged periods of time (minutes). Here we probed the properties and possible anatomical substrate of prolonged neurotransmitter release by using electrical measures of cell surface area as a proxy for neurotransmitter release to study hair cell exocytosis ev...

The aim of the present study was to prepare and characterize controlled-release matrix tablets of zidovudine using hydrophilic HPMC K4 M or Carbopol 934 alone or in combination with hydrophobic ethyl cellulose. Release kinetics was evaluated by using USP XXIV dissolution apparatus No.2 (paddle) type. Scanning electron microscopy was used to visualize the effect of dissolution medium on matrix t...

Metformin hydrochloride has relatively short plasma half-life, low absolute bioavailability. The need for the administration two to three times a day when larger doses are required can decrease patient compliance. Sustained release formulation that would maintain plasma level for 8-12 h might be sufficient for daily dosing of metformin. Sustained release products are needed for metformin to pro...

Purpose: To prepare oral sustained release matrix tablets of a highly water soluble drug, tramadol hydrochloride, and to evaluate the effect of concentration of the hydrophobic polymer content and method of preparation on drug release. Methods: The tablets were a mixture of both tramadol hydrochloride and glyceryl palmitostearate (GP) prepared by melt granulation (MG1, MG2, MG3 and MG4 in ratio...

Circadian clocks sustain daily oscillations in gene expression, physiology, and behavior, relying on transcription-translation feedback loops of clock genes for rhythm generation. Cultured astrocytes display daily oscillations of extracellular ATP, suggesting that ATP release is a circadian output. We hypothesized that the circadian clock modulates ATP release via mechanisms that regulate acute...

Gelucire 50/13 (G50/13) was assessed to develop controlled release formulation of salbutamol sulphate (SBL) a highly water soluble drug by semisolid matrix filling capsule technique. Drug release profiles of SBL release by using G50/13 and its blends with other hydrophilic or hydrophobic materials were investigated. Lipid matrix formulations prepared with increasing amount of polymer showed a s...

The purpose of the present research was to produce a quick/slow biphasic delivery system for aceclofenac. A dual component tablet made of a sustained release tabletted core and an immediate release tabletted coat was prepared by direct compression. Both the core and the coat contained a model drug aceclofenac. The sustained release effect was achieved with polymers hydroxypropyl methylcellulose...

The investigation was concerned with design and characterization of oral controlled release matrix tablets of Zidovudine (AZT) in order to improve efficacy and better patient compliance. Tablets were prepared by direct compression method using various proportion of hydrophilic polymer viz; Eudragit RS100 and RL100 along or in combination with hydrophobic polymer ethyl cellulose. In vitro releas...

In the present study sustained release matrix tablets of Theophylline were prepared by direct compression method using different grades and ratios of hydroxy propyl methyl cellulose in presence of ethyl cellulose to examine their influence on tablet properties and drug release profile. Theophylline is used to treat chronic obstructive pulmonary disease (COPD) and asthma. The drug has a narrow t...