Monica, et al.: Microporous Osmotic Tablets of Venlafaxine HydrochlorideMicroporous osmotic tablets were developed using controlled porosity membrane, which delivers drug in a controlled manner for prolonged period of time. The objective of the present investigation was to formulate and evaluate an oral osmotic drug delivery system for the antidepressant drug venlafaxine hydrochloride to achieve zero order release. Venlafaxine hydrochloride was selected as it has a short biological half-life and high aqueous solubility. Drug-excipient compatibility was studied using Fourier transform infrared spectroscopy. Core tablets were prepared by wet granulation method followed by coating. Sodium chloride and potassium chloride (1:1) were used as osmotic agents in the core tablet and polymers Eudragit RLPO and RSPO (1:1) were used for coating along with sorbitol (70% w/w) as pore formers. The tablets showed desired sustained release profile for 24 h. Optimization studies were performed to study the effect of concentration of osmotic agent and pore former on drug release (t 50% and t 90% ). From in vitro release studies, it was evident that drug release was independent of dissolution media, agitation intensity, but highly dependent on the concentration of pore forming agents, osmotic agent and weight gain of the tablet coating. Scanning electron microscopy confirmed the microporous structure of optimized batch. The optimized formulation gave desired once a day release of venlafaxine hydrochloride without using laser drilling technique, which would make it more patient compliant and cost effective.

Liquisolid technology is very effective technique for improving the solubility and dissolution properties of poorly water soluble drug formulations like Clotrimazole. Clotrimazole is a BCS Class II, antifungal drug used for treatment for Vaginal Candidiasis.  In this liquisolid technique the drug soluble in non volatile solvents and then it converted into free flowing, non adherent powder, which can be compressed into tablet. Here N-methyle-2-pyrrolidone and propylene glycol is used in the ratio of 1:1 as a solvent. Neusilin US2 and Aerosil 200 used as Coating and Carrier material respectively. For mucoadhesion on vaginal wall Sodium carboxymethyle cellulose used as a mucoadhesive agent. Mucoadhesive tablets were prepared using direct compression technique. Magnesium Stearate used as a glidant. Mucoadhesive liquisolid tablets were evaluated as precompression evalutions and post compression evaluations. Future tablets were evaluated as In vitro and Ex vivo evaluations. The optimized batch showed that In vitro release in simulated vaginal fluid pH 4.5 in 6 hr was 99%. Ex vivo diffusion studies of optimized batch showed 80% of drug diffusion in 6 hr. Mucoadhesive strength showed high mucoadhesion of optimized batch that is 36 gm. From this study it was concluded that liquisolid technology is an effective technique to improve solubility and dissolution properties of poorly water soluble drug formulations like Clotrimazole.