الفهرس 
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Abstract
It is reported that drugs applied topically to the eye are rapidly absorbed and available at a desirable site in the eye to exert their therapeutic effect. The viscosity-increasing agents are commonly used to increase the viscosity of the ophthalmic preparations leading to an increase in the ocular contact time, decrease the drainage rate and increase the drug bioavailability. Also, the polymer solutions have a lubricating effect on the eyeball. The main objectives in this investigation were; firstly, to formulate and evaluate some ophthalmic formulations that may possibly be used in the treatment of certain eye diseases. Hence, the work in this thesis deals with the preparation of certain ophthalmic formulations including ophthalmic gels and ocuserts. In-vitro release characteristics and accelerated stability of the prepared formulae were a matter of interest and important target in this investigation. Secondly, in-vivo study has been carried out on some selected stable formulae to ensure the ocular bioavailability of the drug in eye tissues. Furthermore, the effect of the selected formulae containing the drug on the curance time of inflamed rabbits’ eyes was investigated. In this thesis, two drugs were selected; the first drug was triamcinolone acetonide (An anti-inflammatory drug) and the second drug was loratadine (An antiallergic drug). The obtained results revealed that, The tested ophthalmic formulations containing TA-β-CyD complex can be arranged as follows according to the percent released of the drug; HPMC/CP 934 ocuserts > sodium alginate/CP 934 ocuserts > HPMC gel > CP 934 gel > sodium alginate gel. Kinetic analysis of the release data revealed that, the release of TA from the prepared formulations followed two mechanisms, Higuchi and Fickian-diffusion mechanisms. The solubility and the percentage of drug released have been greatly improved by the complexation of the drug with b-CyD. The solubility and the percentage of drug released have been greatly improved by the complexation of the drug with b-CyD. The degradation rate of triamcinolone acetonide followed first-order mechanism. The most stable formulae were, CP 934 gel containing TA-β-CyD complex and HPMC gel containing TA-β-CyD complex. Formulations containing drug-complex with β-CyD proved to be more stable than that containing untreated drug. In all ophthalmic formulations, the highest concentration of the drug uptaken was in conjunctiva followed by cornea, iris-ciliary body and then aqueous humor from all tested formulations except after 6 hr, where the Cmax of the drug was in cornea followed by iris-ciliary body, conjunctiva and then aqueous humor. Also, the obtained results revealed that, there was a linear relationship between the percent drug released from all formulae and the square root of time. This plot indicates a typical-root of time release pattern according to Higuchi equation. Formulations containing drug-complex with β-CyD proved to be more stable than that containing untreated drug. The utilized plain bases showed no curance in the inflamed rabbits’ eyes at the end of the study.