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The potential uses of pharmaceutical grade cellulose in the pharmaceuticaI
industry is the raison d itre for this work. Cellulose was extracted from sawdust
obtained from the tropical tree Gmelinu ai.borea Family Verbenaceae by means of
the classical soda process.
The pure a -cellulose produced was then treated with various concentrations
of trona (sodium sesquicarbonate) 0. I%, I%, 2%, 5%, 15%, and 20% . The trona
treated cellulose named "tronated microfine cellulose "(TMFC) along with
untronated a-cellulose was subsequently subjected to physico-chemical
evaluation. Properties evaluated included microscopical characteristics ,densification
behaviour ,elemental analysis, simple sugar composition, and swelling characteristics
Next, the cellulose powders were then investigated to ascertain their
compatibility with two model drugs namely acetaminophen and ascorbic acid by
means of the temperature stress technique. The celluloses were then employed as
channelling agents in waxy matrix drug delivery systems .These extrusion matrices
were produced using a locally designed and fabricated matrix making unit(MMU).
The matrix forming materials used were dika fat and paraffin wax. Physical
properties of representative samples of the matrices such as weight, dimensions and
friability were determined . Drug release studies were then conducted in 0.1 HCL.
Results of the physicochemical studies revealed that TMFC has the typical
MFC microscopic morphology, bulk volume of between 3.02-5.10cm3 ,bulk density
of 0.28-0.57gl cm3 ,Hausner9s ratio of 1.20-1 .SO and percentage compressibility
of between 34-42 %. The drug compatibility studies revealed no degradation
products. The matrices weighed 400mg on the average, had dimensions of 12mm by
3mm and had friability of O.OS%.The results of the drug release studies indicated that
release followed a diffusion controlled matrix mode!, where the quantity of drug
released is proportional to the square root of time. Further analysis of the release data
revealed that release rate tended to increase with increasing amounts of the
channelling agent. A 15-50% quantity of acetaminophen was released in the first
hour of study with matrices containing higher proportions of channelling agent
having correspondingly higher rates of release. A similar behaviour was observed
with the matrices containing ascorbic acid though at Iower concentration levels.
The results obtained in this study convincingly indicate that cellulose can be
extracted from sawdust, the cellulose so produced can be transformed into a grade of
MFC using trona as an artificial chaperon. It was also found that TMFC can be
successfully employed as a channelling agent in waxy matrix drug delivery system
(WDDS) for oral sustained release formulations.