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An investigation into the influence of drug lipophilicity on the in vivo absorption profiles from subcutaneous microspheres and in situ forming depots.

Deadman, CM; Kellaway, IW; Yasin, M; Dickinson, PA; Murdan, S; (2007) An investigation into the influence of drug lipophilicity on the in vivo absorption profiles from subcutaneous microspheres and in situ forming depots. J Control Release , 122 (1) 79 - 85. 10.1016/j.jconrel.2007.06.013. Green open access

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Abstract

Drug lipophilicity is known to have a major influence on in vivo drug absorption from intramuscularly and subcutaneously administered solutions. Indeed, chemical modification to increase drug lipophilicity is used to enable sustained drug release from solutions. In contrast to the wealth of knowledge on drug release from simple solutions, the influence of drug lipophilicity on its release from controlled release formulations, such as, microparticles and in situ forming depots, have not been systematically studied. Controlled release vehicles are designed to 'control' drug release, hence, in vitro studies show negligible influence of drug lipophilicity on release. The situation could however be different in vivo, due to interactions between the vehicle and biological tissue. We therefore investigated the influence of drug lipophilicity on its in vivo release in rats from two controlled release formulations, PLGA microparticles and in situ forming depots. Both systems exhibited a burst drug release. Subsequent to the burst release, we found that lipophilicity did not influence the rate or extent of drug absorption from the two formulations over a 10-day study period, which would imply that drug partitioning out of the depots was not the main mechanism of drug release from both formulations. This study must however be repeated with a greater number of animals to increase its power.

Type: Article
Title: An investigation into the influence of drug lipophilicity on the in vivo absorption profiles from subcutaneous microspheres and in situ forming depots.
Location: Netherlands
Open access status: An open access version is available from UCL Discovery
DOI: 10.1016/j.jconrel.2007.06.013
Publisher version: http://dx.doi.org/10.1016/j.jconrel.2007.06.013
Language: English
Additional information: This is the author’s version of a work that was accepted for publication in Journal of Controlled Release. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Controlled Release Volume 122, Issue 1, 11 September 2007, Pages 79–85
Keywords: Adsorption, Alprenolol, Animals, Delayed-Action Preparations, Drug Carriers, Drug Implants, Hydrophobic and Hydrophilic Interactions, Injections, Subcutaneous, Lactic Acid, Metoprolol, Microspheres, Polyglycolic Acid, Polymers, Rats
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > UCL School of Pharmacy
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > UCL School of Pharmacy > Pharmaceutics
URI: https://discovery.ucl.ac.uk/id/eprint/1351476
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