DEVELOPMENT AND IN-VITRO EVALUATION OF SOME COLON-SPECIFIC DRUG DELIVERY SYSTEMS

Abstract

Drug targeting to a specific site m the body has emerged as an important area of research. Recent developments in drug delivery systems technology have enabled the colon delivery of some drugs to treat inflammatory bowel diseases. Colon targeting drug release mechanisms rely on the fairly constant small intestinal transit time; which is on average in the order of 3 + 1 hour; during which no measurable dmg release should occur. Only after arrival of the dosage form to the colon that drug delivery may begin. One of the most widely used dmgs to treat colonic inflammatory diseases is mesalazine. The work in this thesis aimed to use mesalazine to prepare promising colon targeted dosage forms.

The thesis started with a short survey on drug targeted delivery systems. Different approaches in the design and evaluation of colon targeted drug delivery systems were reviewed. The thesis is divided into three parts:

Part 1:

The work in this part aimed to prepare mesalazine core tablets coated with innovative cellulose acetate pseudolatex. Cellulose acetate (CA) pseudolatex used in tablet coating was prepared using a novel emulsification process. The oil phase was formed of triethyl citrate as plasticizer and cetostearyl alcohol as hydrophobic surfactant dispersed in "

acetone/ ethanol solvent mixture. The solvent mixture was sonicated till complete solubilization of cetostearyl alcohol. Ceilulose acetate was then dispersed and sonicated till complete solubilization