Design of Controlled Release Non-erodible Polymeric Matrix Tablet Using Microwave Oven-assisted Sintering Technique.

The objective of the present study was to evaluate the effect of sintering condition on matrix formation and subsequent drug release from polymer matrix tablet for controlled release. The present study highlights the use of a microwave oven for the sintering process in order to achieve more uniform heat distribution with reduction in time required for sintering. We could achieve effective sintering within 8 min which is very less compared to conventional hot air oven sintering. The tablets containing the drug (propranolol hydrochloride) and sintering polymer (eudragit S-100) were prepared and kept in a microwave oven at 540 watt, 720 watt and 900 watt power for different time periods for sintering. The sintered tablets were evaluated for various tablet characteristics including dissolution study. Tablets sintered at 900 watt power for 8 min gave better dissolution profile compared to others. We conclude that microwave oven sintering is better than conventional hot air oven sintering process in preparation of controlled release tablets.

A catalytic oxidative esterification of aldehydes using V2O5-H2O2

[reaction: see text] Aldehydes, in the presence of methanol, undergo oxidative transformation to the corresponding esters upon treatment with catalytic amounts of vanadium pentoxide in combination with oxidant hydrogen peroxide. Mild reaction conditions, shorter reaction times, high efficiencies, cost-effectiveness, and facile isolation of the desired products make the present methodology a practical alternative.

Tetrabutylammonium tribromide (TBATB)-MeOH: An efficient chemoselective reagent for the cleavage of tert-butyldimethylsilyl (TBDMS) ethers

TBDMS, THP, and DMT ethers are efficiently deprotected with tetrabutylammonium tribromide in methanol. The apparent order of stability of different protecting group is phenolic TBDMS > 1 degrees OTBDPS > 2 degrees OTBDMS > 2 degrees OTHP > 1 degrees OTHP > 1 degrees OTBDMS > 1 degrees ODMT. TBDMS ether has been cleaved selectively in the presence of isopropylidine, Bn, Ac, Bz, THP, and TBDPS groups. This method is high yielding, fast, clean, safe, cost-effective, and therefore most suitable for practical organic synthesis.

Regioselective bromination of organic substrates by tetrabutylammonium bromide promoted by V2O5-H2O2: an environmentally favorable synthetic protocol

[reaction: see text] Vanadium pentoxide very effectively promotes the bromination of organic substrates, including selective bromination of some aromatics, by tetrabutylammonium bromide in the presence of hydrogen peroxide; mild conditions, high selectivity, yield, and reaction rate, and redundancy of bromine and hydrobromic acid are some of the major advantages of the synthetic protocol.