2 results for Alany, RG

  • Phase transition water-in-oil microemulsions as ocular drug delivery systems: in vitro and in vivo evaluation

    Chan, WYJ; El Maghraby, GMM; Craig, JP; Alany, RG (2007)

    Journal article
    The University of Auckland Library

    Microemuslion (ME)-based phase transition systems were evaluated for ocular delivery of pilocarpine hydrochloride (model hydrophilic drug). These used two non-ionic surfactants, sorbitan mono laurate and polyoxyethylene sorbitan mono-oleate with ethyl oleate (oil component) and water. These systems undergo phase change from ME to liquid crystalline (LC) and to coarse emulsion (EM) with a change in viscosity depending on water content. This study selected five formulations containing aqueous phase at 5% (w/w) (ME 5%), 10% (w/w) (ME 10%), 26% (w/w) (LC), 85% (w/w) (O/W EM) and 100% (solution) with the model drug at 1% (w/w). Incorporation of pilocarpine hydrochloride did not affect the phase behaviour. The viscosity was increased initially with dilution from ME 5% to ME 10% then LC, indicating structuring of the system, before being reduced in the EM formulation. Drug release depended on the viscosity with lower release rates obtained from formulations with high viscosity. The miotic response and duration of action were greatest in case of ME and LC formulations indicating high ocular bioavailability. Thus, phase transition ME is promising for ocular drug delivery as it provides the fluidity with its viscosity being increased after application increasing ocular retention while retaining the therapeutic efficiency.

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  • The effects of supercritical carbon dioxide processing on progesterone dispersion systems: a multivariate study.

    Falconer, James; Wen, Jingyuan; Zargar-Shoshtari, S; Chen, John; Farid, Mohammed; Chan, J; Alany, RG (2012-12)

    Journal article
    The University of Auckland Library

    The aim of this work was to investigate the effects of supercritical carbon dioxide (SC-CO(2)) processing on the release profiles of progesterone (PGN) and Gelucire 44/14 dispersion systems. A fractional factorial design was conducted for optimization of the particles from gas-saturated suspension (PGSS) method and formulation parameters and evaluating the effects of three independent responses: PGSS process yield, in vitro dissolution extent after 20 min (E(20)) and t (1/2) for prepared PGN dispersion systems. The experimental domain included seven factors measured at two levels to determine which factors represent the greatest amount of variation, hence the most influence on the resulting PGN dispersion systems. Variables tested were temperature (A) and pressure (B) of the supercritical fluid, sample loading (C), SC-CO(2) processing time (D), sonication (E), drug-to-excipient ratio (F) and orifice diameter into the expansion chamber (G). The analysis of variance showed that the factors tested had significant effects on the responses (p value <0.05). It was found that the optimum values of the PGSS process are higher pressure (186 bar), higher temperature (60°C), a longer processing time (30 min) and lower PGN-to-excipient ratio of 1:10. The corresponding processing yield was 94.7%, extent of PGN dissolution after 20 min was 85.6% and the t (1/2) was 17.7 min. The results suggest that Gelucire 44/14-based dispersion systems might represent a promising formulation for delivery of PGN. The preparation of PGN-loaded Gelucire 44/14 dispersion systems from a PGSS method can be optimized by factorial design experimentation.

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