Absorption, distribution, and metabolic fate of seclazone (7-chloro-3,3a-dihydro-2H,9H-isoxazolo(3,2-b) (1,3)benzoxazin-9-one)

Synthesis and Cytotoxicity of Salicylate-Based Poly(anhydride esters)

This paper describes the synthesis and cytotoxicity of poly(anhydride esters) that are composed of several salicylate derivatives, including halogenated salicylates, aminosalicylates, salicylsalicylic acid, and thiolsalicylic acid. The incorporation of these nonsteroidal antiinflammatory drugs (NSAIDs) into a biodegradable polymer backbone yields drug-based polymers that have potential for a variety of applications. The poly(anhydride esters) were synthesized by melt condensation polymerization. The halogenated salicylate derivatives yielded the highest molecular polymers as well as the highest glass transition temperatures. All polymers displayed in vitro degradation lag times from 1 to 3 days, depending on the water solubility of the salicylate derivative. Cell viability and proliferation were determined with L929 fibroblast cells in serum-containing medium to assess the polymer cytotoxicities, which varied as a function of the saliyclate chemistry. Cell morphology was normal for most of the polymers evaluated.

Absorption, distribution, and metabolic fate of 7-chloro-3,3a-dihydro-2-methyl-2H,9H-isoxazolo-(3,2-b)(1,3)-benzoxazin-9-one in rats, dogs, and humans

The absorption and metabolic fate of 7-chloro-3,3a-dihydro-2-methyl-2H,9H-isoxazolo-(3,2-b)(1,3)-benzoxazin-9-one (I) was studied in rats, dogs, and humans. Orally administered I was readily absorbed by all species. In the rat, orally administered I was converted to its metabolite, 5-chlorosalicylic acid, by the intestinal wall. The half-lives of blood radioactivity, after the oral administration of I-9-14C, were about 18 and 12 hr in the rat and beagle hound, respectively. In human subjects, no intact I was detected in the bloodstream; however, the clearance of the metabolite, 5-chlorosalicylic acid, had a half-life of about 33 hr. Cleavage of the oxazine ring of I generated 5-chlorosalicylic acid, which was excreted both in the free form and conjugated with glycine and glucuronic acid. The isoxazole moiety was converted to beta-hydroxybutyric acid and its metabolites carbon dioxide and fumaric, citric, alpha-ketoglutaric, succinic, and malic acids. Binding of I to plasma proteins was extensive but was less than that of 5-chlorosalicylic acid.