الفهرس 
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Abstract
In spite of the wide and ever increasing range of applicatioris of polyethylene glycols in pharmaceutical research, evelopwent and dosage form design, particularly in ointment, Suppository and table manufacture, it appears from literature ht no trials have been done to investigate the use of polyethylene glycols in the field of inicroencapsulation of drugs.
The work in this thesis represents trials for utilizing olyethylene glycols 000 and 20000, in encapsulating three of the xygen sensitive drugs, with the aim of investigating the pro— ective effect that may be offered by the encapsulation process.
Microencapsulation was achieved by two congealing techniques. The first is relatively new and was not reported in literature. It is based on dispersing the medicament and the molten PEG in hot liquid paraffin with the aid of mechanical stirring in the presence of a suitable emulsifier (Span O), ollowed by congealing and separation of the wicrocapsules by the addition of a cold nonsolvent (petroleum ether).
The second technique-the phase separation technique — volves the preparation of a solution of the polyethylene gly— ccl in a suitable solvent (chloroform) in which the insoluble ug is homogeneously dispersed by stirring. Another liquid, ich is miscible with the polymer solvent, but is nonsolvent or the polymer and the dispersed particles, is added while irring, where phase separation and congealing of PEG