Classification of benzoyl peroxide as safe and effective and revision of labeling to drug facts format; topical acne drug products for over-the-counter human use; final rule.

We, the Food and Drug Administration (FDA), are issuing this final rule to include benzoyl peroxide as a generally recognized as safe and effective (GRASE) active ingredient in over-the-counter (OTC) topical acne drug products. In addition, this final rule includes new warnings and directions required for OTC acne drug products containing benzoyl peroxide. We are also revising labeling for OTC topical acne drug products containing resorcinol, resorcinol monoacetate, salicylic acid and/or sulfur to meet OTC drug labeling content and format requirements in a certain FDA regulation. This final rule is part of our ongoing review of OTC drug products and represents our conclusions on benzoyl peroxide in OTC acne drug products.

Searching for new NO-donor aspirin-like molecules: a new class of nitrooxy-acyl derivatives of salicylic acid.

A new class of products in which the phenol group of salicylic acid is linked to alkanoyl moieties bearing nitrooxy functions has been synthesized and studied for their polyvalent actions. The products were stable in acid and neutral media, while they were hydrolyzed in human serum. Their half-lives were dependent upon the structure of alkanoyl moieties. The products showed anti-inflammatory activities similar to aspirin when tested in the carrageenan-induced paw edema assay in the rat. Interestingly, unlike aspirin, they showed reduced or no gastrotoxicity in a lesion model in rats at equimolar doses. A number of them were able to inhibit platelet aggregation induced by collagen in human platelet-rich plasma. All of the products were capable of relaxing rat aortic strips precontracted with phenylephrine in a concentration-dependent manner. Selected members of this new class of nonsteroidal anti-inflammatory drugs might represent possible safer alternatives to aspirin in different clinical settings.

Three Tnt1 subfamilies show different stress-associated patterns of expression in tobacco. Consequences for retrotransposon control and evolution in plants.

The genomes of most Nicotiana species contain three different subfamilies of the Tnt1 retrotransposon, which differ completely in their U3 sequence, whereas the rest of the sequence is relatively constant. The results presented here show that all three Tnt1 subfamilies are expressed in tobacco (Nicotiana tabacum) and that the U3 sequence variability correlates with differences in the pattern of expression of the Tnt1 elements. Each of the three Tnt1 subfamilies is induced by stress, but their promoters have a different response to different stress-associated signaling molecules. The Tnt1A subfamily is particularly strongly induced by elicitors and methyl jasmonate, whereas expression of the Tnt1C subfamily is more sensitive to salicylic acid and auxins. The direct relationship between U3 sequence variability and differences in the stress-associated expression of the Tnt1 elements present in a single host species gives support to our model that postulates that retrotransposons have adapted to their host genomes through the evolution of highly regulated promoters that mimic those of the stress-induced plant genes. Moreover, here we show that the analysis of the transcriptional control of a retrotransposon population such as Tnt1 provides new insights into the study of the complex and still poorly understood network of defense- and stress-induced plant signal transduction pathways.