The possibility of preparation of ophthalmic drug delivery systems using compressed anti-solvent technology was evaluated. Eudragit RS 100 and RL 100 were used as drug carriers, acetazolamide was the model drug processed. Compressed anti-solvent experiments were carried out as a semi-continuous or a batch operation from a liquid solution of polymer(s)+solute dissolved in acetone. Both techniques allowed the recovery of composite particles, but the semi-continuous operation yielded smaller and less aggregated populations than the batch operation. The release behaviour of acetazolamide from the prepared microparticles was studied and most products exhibited a slower release than the single drug. Moreover, the release could be controlled to some extent by varying the ratio of the two Eudragit used in the formulation and by selecting one or the other anti-solvent technique. Simple diffusion models satisfactorily described the release profiles. Composites specifically produced by semi-continuous technique have a drug release rate controlled by a diffusion mechanism, whereas for composites produced by the batch operation, the polymer swelling also contributes to the overall transport mechanism.

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The synthesis, characterization, and application as CVD precursors of several new dimethyl(norbornadienyl)platinum(II) compounds are reported. Initially, synthesis is performed in a two-step procedure from K 2 PtCl 4 with (Rnbd)PtI 2 as an intermediate, but a convenient "one-pot" procedure is developed that allows the formation of platinum(II) precursors with good yield and purity. Novel platinum compounds are; (nbd)PtMe 2 (1), (7-Me-nbd)PtMe 2 (2), (7-Et-nbd)PtMe 2 (3), (7-i Pr-nbd) PtMe 2 (4), and (2-Et-nbd)PtMe 2 (5). Compounds 1 À 4 are solids while 5 is liquid at room temperature. Fine-tuning of the organic environment provides some control of the thermal stability and volatility. Liquid-delivery CVD is reported using 1 and 5 Pt precursor solutions. Excellent results are obtained in the presence of oxygen as a co-reactant. The as-deposited Pt films are analyzed in terms of morphology, crystalline structure, and composition.