Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569355
Title: Characterisation and performance assessment of semi-solid dispersions using surface active lipidic carriers
Author: Otun, Sarah Oladeinde
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2011
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Abstract:
Semi-solid dispersions offer many advantages in the delivery of poorly soluble drugs. However, there is limited understanding of the mechanisms by which in vitro dissolution and in vivo bioavailability is enhanced. Low melting point lipidic carrier excipients demonstrate properties beneficial to formulation of these systems despite presenting further challenge in their characterisation. The physicochemical properties of semi-solid dispersions comprising the lipidic carrier Gelucire 44114 with the poorly soluble drugs ibuprofen, indometacin and piroxicam were investigated. Conventional differential scanning calorimetry demonstrated dissolution effects, the slow rate allowing crystalline drug to dissolve within the molten lipid during analysis giving unreliable data regarding the presence of solid crystalline drug in proportion to that existing as a molecular dispersion. Hyper DSC was not definitively found to eliminate these effects; however they were reduced, giving a more accurate estimation of the drug solubility within the lipid. The drugs demonstrated different affinities for the lipid with subsequent effects on the extent of interaction. The presence of drug in the lipid demonstrated a significant inhibitory effect on the lipid crystallisation temperature, with QIMTDSC demonstrating a more extended crystallisation than expected. The dissolution properties of all drugs were enhanced when formulated into semi-solid dispersions with Gelucire 44/14, most notably with the low loaded systems. These low loaded systems, however, demonstrated an increased affinity for atmospheric moisture. Aging effects on the semi-solid dispersions were observed with ibuprofen and indometacin systems in which the drug was found to exist partially as a molecular dispersion. Piroxicam however, which had very limited miscibility with the lipid, was found to exhibit few aging effects over time. Overall, the formulated semi-solid dispersions with Gelucire 44114 achieved the ultimate goal of successfully enhancing the aqueous dissolution of poorly soluble drugs, however more research is needed in order to relate this successfully to in vivo bioavailability.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.569355  DOI: Not available
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