الفهرس 
Abstract
Results and discussionOnly 14 pages are availabe for public view
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Abstract
Today, topical ophthalmic application is considered as the desired way to achieve the therapeutic level of the drug to treat the ocular diseases. The drugs administered topically to the eye are rapidly absorbed at the desired site of action to exert their therapeutic effect. Bioavailability of ocular drops ranges from 1 to 10% of the total administered dose due to the rapid clearance resulting from reflex tearing and blinking. The viscosity increasing agents are used to increase the viscosity of the ophthalmic preparations, leading to increase drug bioavailability by two ways; increase the drug ocular residence time and decreasing the drainage rate. Also, the polymers have a lubricating effect on the eye tissues. Hence, the work in this thesis deal with the formulation of certain ophthalmic preparations including ophthalmic drops, microemulsions, gels, in-situ gels and ocuserts using different drug carriers. In-vitro release characteristics were a matter of interest and important target in this investigation. Also, in-vivo study has been carried out on some selected formulae to ensure the ocular availability of the drug in eye tissues. In this thesis, two drugs were selected; the first drug was econazole nitrate (antifungal agent) and the second one was moxifloxacin hydrochloride (antibacteril agent). The thesis includes the following two parts: In part one (chapter one); from the obtained results, it was evident that; Econazole nitrate cyclodextrin complexes was successfully formulated as drops, gels and ocuserts using different polymers combinations. The solubility and the rate of drug release improved by complexation with β-CyD or HP- β-CyD. Furthermore, HP- β-CyD has a higher solubilizing effect for EC than β-CyD. The amount of drug released from different formulations, is varied according to complex types, polymer types and dosage forms. The amount of the drug released from eye drops and gels were higher than that released from ocuserts. Generally, the tested formulations were arranged in the following order; eye drops > eye gels > ocuserts. While, in chapter two: The obtained results showed that, the peak time for maximum concentration of the drug from tested formulations in eye tissues and aqueous humor after instillation in rabbits eyes was 3 hrs for eye drops, eye gels and ocuserts. In all ophthalmic preparations, econazole nitrate was available in cornea in a higher concentration than in conjunctiva. While iris- ciliary body and aqueous humor at all time intervals showed low drug concentration. The entire bioavailability of econazole nitrate when prepared as complex with HP-β -CyD was improved more than that complexed with β-CyD. Regarding the ocular bioavailability of the drug from the tested formulations, it can be arranged in the following order; EC-HP-β–CyD< EC-β–CyD < EC alone. In part two (chapter one) moxifloxacin hydrchloride 0.5 w/v % was effectively formulated as microemulsions, in-situ gels and ocuserts using different polymers combinations. The amount of drug released from different formulations, it was found that, the drug release is varied according to; polymer types and dosage forms. The amount of the drug released from eye microemulsions, in-situ gels were higher than that released from ocuserts. Generally, the amount of the drug released from the tested formulations were arranged in the following order; microemulsions > in-situ gels > ocuserts. While, in chapter two: The obtained results showed that, the peak time for maximum disposition of the drug from selected formulations in eye tissues and aqueous humor after instillation in rabbits eyes was 2 hrs for microemulsions, in-situ gels and ocuserts. In all ophthalmic preparations, moxifloxacin hydrochloride was available in conjunctiva in a higher concentration than in cornea. Additionally, iris- ciliary body and aqueous humor showed low drug concentration. Regarding the relative bioavailabilities of ocuserts were higher than that of in-situ gels and eye microemulsions.