Controlled release formulations offer many advantages over conventional dosage forms.
These include reduced plasma fluctuations and improved patient comp1i:nce. Complex
controlled release formulations such as those with enteric release properties, often require
additional steps in the production phase. The costs and economic impact associated with
these complex controlled release dosage formulations often outweigh the immediate
benefits. Thus the development of an economic method to produce controlled release
particles is of great importance especially in third world countries.
In controlled release formulations, the drug is generally dispersed throughout a polymer
matrix. The rate of drug release is often determined by the viscosity or complexity of the
polymer matrix through which the drug needs to diffuse in order to be released. With
enteric release the polymer coating, insoluble in an acidic environment is often applied in
the final phase of production.
Chitosan is a versatile polymer of natural origin with many favourable characteristics.
These include its safety, biocompatibility, and biodegradability. Simple methods can be
applied and modified to produce controlled release particles form chitosan. The effect of
modern controlled release polymers such as Aqoat AS-HF, Eudragit SlOO and
Kollidon SR was investigated.
Chitosan beads and chitosan-polymer beads, as well as chitosan granules and chitosan-polymer
granules, were prepared and investigated as possible controlled release
formulations. Ketoprofen was chosen as the model drug. Chitosan beads and chitosan-polymer
beads were prepared by inotropic gelation in tripolyphosphate. Chitosan
granules and chitosan-polymer matrix granules were prepared by binding chitosan with
an acetic acid solution as a granulating system. The beads and granules appeared differed
in appearance as well as in the results obtained from various experiments. Granules
prepared in the study did not appear to be effective with regards to enteric and controlled
release. Beads prepared form Kollidon SR appeared to be effective with regards to
enteric and controlled release, with Kollidon 1% and 5% w/v chitosan beads achieving
good drug loading of up to 73.13% and releasing less than 15 % of the total drug content
in 0.1 M HCI after 60 minutes. Drug release continued steadily for up to 360 minutes in
pH 7.2. It was concluded that Kollidon SR loaded chitosan beads nay be a viable
controlled release dosage form with enteric release properties, and that future
experiments, possibly with lower polymer concentrations, are worthwhile / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2006.
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/1034 |
| Date | January 2005 |
| Creators | Verwey, Werner Jaun |
| Publisher | North-West University |
| Source Sets | North-West University |
| Detected Language | English |
| Type | Thesis |
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