الفهرس 
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Abstract
Recently, it has seen an increasing interest in the development of mucoadhesive drug delivery systems. The potential of mucoadhesive polymers in prolonging the residence time of the dosage forms and the absorbing tissues improve the systemic drug delivery as well as local targeting effect. The main objectives in this investigation were; firstly, to design buccal mucoadhesive tablets containing captopril, used for the treatment of hypertension and congestive heart failure, using different polymers either singly or in blends of different ratios (carbopol 934, Eudragit RS 100, chitosan, hydroxpropyl methylcellulose and polyvinylpyrrolidone K30). In-vitro release characteristics and the physicochemical properties of the prepared tablets were studied. In addition, the bioavailability and the pharmacokinetic parameters of captopril from selected formulations were also studied. Secondly, to evaluate some ophthalmic drug delivery systems containing levofloxacin that used to treat external infections of the eye. Hence, the work in this part was to study the formulation of certain ophthalmic preparations having mucoadhesive properties like; in-situ gelling systems, DROPs, performed gel and ocular inserts. In-vitro release characteristics and stability of the prepared formulae were of our goals. Also, the effect of the most stable drug formulae on the healing time of the infected and inflamed rabbits eyes will be investigated. The obtained results revealed that, captopril can be formulated as buccoadhesive tablets. Also, the drug release is varied with the polymer types and the ratios of polymer in each formulation. Regarding to the mucoadhesive performance for carbopol 934 and chitosan, these polymers possess the maximum bioadhesion force. In case of polymers blend, it was found that, the addition of HPMC to carbopol 934 or chitosan, reduces the bioadhesion force and residence time. On the other hand, the addition of HPMC to PVP K30 or Eu RS 100 can enhance the adhesive properties of them. Captopril buccoadhesive tablets containing carbopol 934 : HPMC (CH 3) and chitosan : HPMC (KH 3) showed higher bioavailability and more efficient sustained-release effect than the control tablets. This indicated by low Cmax values and high AUC values compared to the control tablets. Also, the obtained results revealed that, levofloxacin can be formulated successfully as in-situ gelling systems, DROPs and performed gel using positively charged polysaccharide (chitosan) and ocular inserts using different polymers combinations. from the obtained results, the amount of the drug released from eye DROPs (in-situ gelling systems and chitosan DROPs) and performed gel were higher than that released from ocular inserts. The drug retained its antimicrobial efficacy when formulated as these ophthalmic drug delivery systems and the drug was active against the selected strains of microorganisms. The drug showed a great stability up to 6 months of storage at different temperatures. Formulae containing levofloxacin using sodium alginate and HPMC either formulated as in-situ gelling systems or ocular inserts were suggested to be the most physically and chemically stable formulae. While, the formulae containing the drug using chitosan and HPMC either formulated as performed gel or ocular inserts are the least stable formulae. After treatment of inflamed rabbits eyes with formulation containing the drug, the ulcers were healed and the denuded layers were completely regenerated and the eye tissues become nearly normal.