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The aim of the present study was to evaluate the in vitro percutaneous absorption and the in vivo anti-inflammatory activity of EPA and DHA fatty acids from three oily extracts, obtained by acetonic extractions from the entrails of different varieties of Mediterranean fishes such as mackerel (Scomber scombrus), sardine (Sardina pilchardus) and horse mackerel (Trachurus mediterraneus). In the first part of our research, we focused our attention on the characterization of the oily extracts to determine their omega-3 polyunsaturated fatty acid content, then, we evaluated the in vitro percutaneous absorption through excised human skin (stratum corneum/epidermis membranes; SCE) of EPA and DHA contained in the extracts. In the second part, the fish oil which guaranteed the best in vitro permeation profile of these omega-3 fatty acids was studied in order to evaluate its inhibiting ability towards the in vivo UVB-induced skin erythema. From the results obtained, all the fish oils tested in this study presented significant amounts of omega-3 fatty acids EPA and DHA, and particularly sardine oil extract showed higher concentrations of these substances compared to the other two fish oils. The in vitro experiments revealed interesting fluxes of these compounds from sardine extract through the stratum corneum/epidermis membranes and an appreciable anti-inflammatory activity against UVB-induced erythema in human volunteers was also observed.

Six new 1-alkylazacycloalkan-2-one esters of ketoprofen (1-6) were synthesized and evaluated as potential dermal prodrugs of ketoprofen. Their lipophilicity by both experimental lipophilicity indices (log k') and calculated ClogP was also determined. In vitro experiments were carried out to evaluate the chemical and enzymatic stability and permeation through excised human skin of these new ketoprofen derivatives. Furthermore, we investigated the in vivo topical anti-inflammatory activity of ester 5, which showed the best in vitro profile, evaluating the ability of this compound to inhibit methyl nicotinate-induced skin erythema on healthy human volunteers. Esters 1-6 showed increased lipophilicity compared with the parent drug (ketoprofen), good stability in phosphate buffer pH 7.4, and were readily hydrolyzed by porcine esterase. Results from in vitro percutaneous absorption studies showed that, among all esters synthesized, only for esters 1 and 5 did a higher cumulative amount of drug penetrate through the skin, compared with that obtained after topical application of ketoprofen. In vivo results showed an interesting delayed and sustained activity of ester 5, compared with the parent drugs.

Polyoxyethylene esters of ketoprofen (1a-e), naproxen (2a-e) and diclofenac (3a-e) were tested in vitro to determine their stability in pH 7.4 phosphate buffer and in simulated gastric fluid (pH 2.0 buffer) and their susceptibility in undergoing enzymatic cleavage in human plasma. Furthermore their in vivo antiinflammatory and analgesic activity and GI toxicity were evaluated in rodents. All the prodrugs showed a good stability both in pH 7.4 phosphate buffer and in pH 2.0 buffer. They were readily hydrolyzed by human plasma and, for each group of prodrugs, no significant difference in hydrolysis rate was observed as the length of the oligoethylene chain increased. Esters 1a-e, 2a-e and 3a-e showed an anti-inflammatory activity (expressed as inhibition percent of carrageenan-induced edema in the rat) similar to that of their respective parent drug although at higher doses. The results obtained in the writhing test in mice demonstrated that all the prodrugs tested exhibited, following acute administration, a good analgesic effect. Furthermore these esters were significantly less irritating to the gastric mucosa, although administered at doses higher than the respective parent drug.

Six ketoprofen (CAS 22071-15-4) alkylazacycloalkan-2-one ester derivatives (I-VI) were synthesized and evaluated for their anti-inflammatory, analgesic, and ulcerogenic activities after oral administration. Furthermore these derivatives were assayed to determine in vitro their stability in pH 7.4 phosphate buffer and in simulated gastric fluid (pH 2.0 buffer) and their susceptibility to enzymatic cleavage in rat plasma. All the prodrugs showed a good stability both in pH 7.4 phosphate buffer and in pH 2.0 buffer, and they were readily hydrolyzed by rat plasma. Esters I-VI showed an anti-inflammatory activity, determined as the percent of inhibition of carrageenan-induced edema, similar to that of ketoprofen, although at higher doses. They were significantly less irritating to the gastric mucosa than the parent drug. In the mouse acetic acid induced writhing assay, the prodrugs exhibited, following acute administration, a good analgesic activity.