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Thin films, which are able to deliver antibiotics in a controlled way, are considered as a promising approach to combat bacterial infections. A novel drug delivery method based on reservoir/diffusion barrier is introduced in this paper. As reservoir serves a film of sputtered nylon 6,6 impregnated with ampicillin, which is then covered by a diffusion barrier from the same material. It is demonstrated that the impregnation process does not affect either the morphology or the surface chemical structure. The amount of immobilized antibiotics can be tailored by changing the reservoir film thickness, while the release kinetics can be controlled by the thickness of the diffusion barrier. Finally, it is shown that the ampicillin impregnated films have an antibacterial effect against Staphylococcus epidermidis.

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Photochemical degradation of fluoroquinolones ciprofloxacin, enrofloxacin and norfloxacin in aqueous solution under light conditions relevant to surface waters at neutral and alkaline pH was found to proceed readily with half-lives between 0.9 and 2.7 min. The products of photochemical degradation identified by HPLC-MS included defluorinated, hydroxylated, and decarboxylated structures as well as structures with opened cyclic structures. For all of the studied substances, the reaction pathways were influenced significantly by the pH of the reaction system, with more products formed at alkaline pH than at neutral pH: the ratios of products in neutral and alkaline pH were 16/26, 9/19, 15/23 for ciprofloxacin, enrofloxacin, and norfloxacin, respectively. The structures of photoproducts and pathways of photochemical degradation are proposed. The antibacterial activities of photoproduct mixtures tested on E. coli and S. epidermidis were significantly higher in comparison to parental antibiotics in the case of both ciprofloxacin and enrofloxacin with p-values less than 0.0001 in most cases. The effect of the photoproducts was shown to be dependent on the pH value of the original antibiotic solutions before photodegradation: for ciprofloxacin, antibacterial activity against E. coli was more notably pronounced with regard to neutral pH photoproducts, while a less significant, or in one case not significant, effect of pH was observed against S. epidermidis ; for norfloxacin, antibacterial activity against both E. coli and S. epidermidis were especially high with regard to alkaline pH photoproducts

Photochemical degradation of uoroquinolones cipro oxacin, enro oxacin and nor oxacin in aqueous solution under light conditions relevant to surface waters at neutral and alkaline pH was found to proceed readily with half-lives between 0.9 and 2.7 min. The products of photochemical degradation identi ed by HPLC-MS included de uorinated, hydroxylated, and decarboxylated structures as well as structures with opened cyclic structures. For all of the studied substances, the reaction pathways were in uenced signi cantly by the pH of the reaction system, with more products formed at alkaline pH than at neutral pH: the ratios of products in neutral and alkaline pH were 16/26, 9/19, 15/23 for cipro oxacin, enro oxacin, and nor oxacin, respectively. The structures of photoproducts and pathways of photochemical degradation are proposed. The antibacterial activities of photoproduct mixtures tested on E. coli and S. epidermidis were signi cantly higher in comparison to parental antibiotics in the case of both cipro oxacin and enro oxacin with p-values less than 0.0001 in most cases. The effect of the photoproducts was shown to be dependent on the pH value of the original antibiotic solutions before photodegradation: for cipro oxacin, antibacterial activity against E. coli was more notably pronounced with regard to neutral pH photoproducts, while a less signi cant, or in one case not signi cant, effect of pH was observed against S. epidermidis ; for nor oxacin, antibacterial activity against both E. coli and S. epidermidis were especially high with regard to alkaline pH photoproducts