الفهرس 
ACKNOWLEDGEMENTSOnly 14 pages are availabe for public view
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Abstract
The objective of this thesis was to formulate and characterize the solid dispersion of Celecoxib (CXB) with a number of hydrophilic polymers (Hydroxyl propyl beta cyclodextrin (HP-β-CD), Poly vinyl pyrrolidone (PVP K 30) and Urea). This was done by two techniques (spray drying and solvent evaporation). Also, to formulate and characterize the microcapsules of CXB with two hydrophobic polymers ( Ethyl cellulose (EC) and Cellulose acetate butyrate (CAB)) by emulsion solvent evaporation method. The work aimed to investigate the possibility of improving and controlling the in-vitro drug release and dissolution of CXB. These investigations together with the obtained results and the conclusions can be summarized as follows:
1- The solubility of CXB increased in a linear fashion as a function of hydrophilic polymers concentration.
2- The values of the production yield of the prepared solid dispersions and microcapsules ensured the recoverability of the formulations. The drug content indicated that the drug was uniformly dispersed in all formulations. So, the methods used appeared to be reproducible.
3- The observations obtained for IR spectroscopy and thermal analysis showed that there was no chemical interaction between the drug (CXB) and the polymers in solvent evaporation and emulsion solvent evaporation methods. While, in case of spray drying, the drug may be enclosed within the polymer.
4- By determination of the micromeritic properties of CXB solid dispersions and microcapsules, it was found that almost formulae from all methods showed excellent flowability.
5- Hydrophilic polymers enhanced the in-vitro release of CXB to a considerable extent, while hydrophobic polymers delayed the release.
6- Spray drying technology showed higher improvement in the dissolution rate of the drug using the same polymers in comparison with the solvent evaporation.
7- Kinetics of the in-vitro release of CXB from capsules containing solid dispersions obeyed first kinetic order. While, CXB from capsules containing microcapsules followed Higuchi’s diffusion model.
8- Formulae E8, D8 and M3 (from each method) were found to give the best data after preforming all previous tests
10- CXB solid dispersions were helpful in improving the analgesic effects of CXB. But, the analgesic effect of CXB microcapsules was delayed due to retardation by the polymer coat.