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Title: Rational formulation design of pharmaceutical and cosmetic actives
Author: Patel, A. M.
ISNI:       0000 0004 6062 9548
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2017
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The skin is the outermost organ vital for human life. Its unique structure creates a formidable barrier, one that must be overcome for the delivery of pharmaceutical and cosmetic actives. Ibuprofen is often used for the short term management of musculoskeletal conditions and is applied topically for local delivery. Retinyl palmitate is a vitamin A derivative commonly included in cosmetics as an anti-ageing ingredient. Both model actives were formulated based on their physiochemical properties and solubility or miscibility with selected excipients. Clinically relevant or finite doses were used throughout to simulate point of use conditions. Ibuprofen was prepared in volatile formulations and after evaporation of alcohol only ibuprofen and the excipient remained on the skin. The in vitro permeation of ibuprofen using Franz diffusion cells was initially studied through silicone membranes and porcine skin. Neither of these model membranes were comparable to human skin. Permeation and mass balance studies using human skin were carried out for ibuprofen and the vehicle. This was to determine the vehicle fate and to establish its role during the permeation process. The use of human skin mounted in Franz diffusion cells was also used to determine the penetration of retinyl palmitate from single and binary vehicle formulations. Mass balance studies were primarily used to determine the penetration of both retinyl palmitate and the vehicle. Analysis was also performed for retinol, a metabolite of retinyl palmitate. Finally an in vivo study using confocal Raman spectroscopy was performed on human subjects. Volatile ibuprofen formulations were applied and the delivery of ibuprofen and vehicle to the stratum corneum was determined. A good relationship between in vitro and in vivo data was observed. Overall the formulation strategy adopted demonstrates that a rational selection of the vehicle can deliver enhanced efficacy of topical formulations.
Supervisor: Lane, M. E. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available