Evaluation of emulsification kinetics of oil in water

• Author(s): Aruna, Santhagunam, 1980-
• Date: 2009
• Persistent ID: http://hdl.handle.net/10451/234
• Origin: Repositório da Universidade de Lisboa
• Subject(s): Farmacocinética; Teses de mestrado
• Document Type: Master thesis
• Language: English
• Advisor(s): Pinto, João Fernandes de Abreu, 1963-; Sousa, João Melo de
• Contributor(s): Repositório da Universidade de Lisboa

Description

Tese de mestrado, Farmacotecnia Avançada, 2009, Universidade de Lisboa, Faculdade de Farmácia

Emulsions are the complex fluids and their stability depends, or is reflected by the size of the emulsion droplets which is considered to be critical. In the design and study of an emulsification process, knowledge of factors governing the particle size and size distribution of the droplets is an important consideration. The study of kinetics of emulsification involves various parameters and the droplet sizing is a significant one. In this work the effects of various experimental factors has been carried out to study the kinetics of emulsification of oil in water (e.g. agitation duration, agitation rate, surfactant concentration, oil concentration, ageing). Sizing of droplets was carried out by Phase Doppler Anemometry (PDA), Photo Correlation Spectroscopy (PCS), Laser Diffraction (LD) and Microscopy. The effect of these parameters during the emulsification process was studied and the reason for imparting significance on these parameters is for the fact that controlling these critical parameters can assist to obtain a desired final product as this paves the path for achieving the quality aspect of being Right at the first time which is a central issue in Quality by Design (QbD). The comparison of size distribution obtained by these sizing methods was studied. Results have shown that by increasing agitation duration and rate a decrease in droplet diameter was observed, surfactant concentration cause a decrease in droplet diameter and an increase in oil concentration increased the droplet diameter. Ageing has also shown an increase in droplet diameter. Regarding the techniques considered, PDA was limited by the imposed dilution on emulsions to allow measurements, PCS was used at the marginal upper limit range thus care had been taken to present accurate measurements, LD was sensitive to dilution of samples prior to measurements and Microscopy, a tedious technique difficult to use and when limited samples are used one may have non representative results. The possibility of using Phase Doppler Anemometry (PDA) as online monitoring equipment (as a Process Analytical Technology) was discussed where the emulsion droplets could be assessed online there by contributing to the real time emulsification control was discussed. The study of viscosity of these emulsions was done as this is one of the significant criteria for the quality control aspects. From the techniques used, PDA seems to be most adequate as online/inline equipment for monitoring the process of emulsification.