Mechanisms of Action of Sunscreens

Sunscreens delay the induction of sunburn by absorbing or reflecting a portion of the UVR reaching the epidermis. Organic sunscreens are aromatic compounds that absorb light energy in the UV region, and therefore reduce the amount of UVR reaching the stratum cor-neum. A benzene ring has the ability to transform high energy UVR into harmless long wave radiation above the 380-nm range, which is emitted from the skin as heat (294). The conversion of UVR to longer wavelength occurs through...

OTC Classification in Japan

Drugs in Japan are classified into prescription, non-prescription (OTC), and quasi-drug. Prescription drugs are those drugs that require physician supervision (50-53). Non-prescrip-drugs are primarily for mild actions and are only available in the pharmacy or drug store. Deregulation reform reclassified 15 categories of non-prescription drugs to create a new class of drugs called quasi-drugs, which can be sold in convenience stores and supermarkets starting in Spring 1999 (51). Quasi-drugs are...

SAR of Bupropion and Its Analogs

Bupropion (15), also known as amfebuta- mone, is ethyl)amino -l-propane. It is a trimethylated monocyclic phenylaminoketone and is structurally unrelated to the tricyclic antidepres-sants or MAO inhibitors. Commercially available bupropion is a racemic mixture. The two enantiomers were synthesized and assayed for their potencies as inhibitors of biogenic amine uptake into nerve endings obtained from mouse brain (212). No significant difference was found. However, the relative pharmacological...

Chemistry and Structure Activity Relationships

Sildenafil (6) is a pyrazolopyrimidinonederiv-ative. The pyazolopyrimidinone ring is essential for PDE5 inhibitory activity. It seems that this ring structure mimics the guanosine base of cGMP (149). Another ring system that has been shown to produce potent and selective PDE5 inhibitory activity is imidazoquinazoli- none (150). In the sildenafil series, the n-pro-pyl substitution on position 3 of the pyazolopy-rimidinone ring gives a more potent compound compared with a 3-methyl analog....