Photodegradation of Bexarotene and Its Implication for Cytotoxicity.

A detailed understanding of the stability of an active pharmaceutical ingredient and a pharmaceutical dosage form is essential for the drug-development process and for safe and effective use of medicines. Photostability testing as an inherent part of stability studies provides valuable knowledge on degradation pathways and structures of products generated under UV irradiation. Photostability is particularly important for topically administered drugs, as they are more exposed to UV radiation.

Photostability Testing of a Third-Generation Retinoid-Tazarotene in the Presence of UV Absorbers.

Exposure of a drug to UV irradiation could affect its physicochemical properties. Hence, photostability testing is essential for topically administered drugs. Tazarotene, a receptor-selective, third-generation retinoid, is commonly used to treat acne vulgaris and psoriasis.

Synthesis and Transformation of (-)-Isopulegol-Based Chiral -Aminolactones and -Aminoamides.

A library of isopulegol-based -amino acid derivatives has been developed from commercially-available (-)-isopulegol. Michael addition of primary and secondary amines towards ,-unsaturated -lactones was accomplished resulting in -aminolactones in highly-stereoselective reactions. Ring-opening of -aminolactones with different amines furnished excellent yields of -aminoamides.

New iridoids from the roots of Valeriana dioscoridis Sm.

Four new iridoids (1-4), together with three known iridoids (5-7), one known flavonoid glycoside, three phenolic acids and one phytosterol were isolated from the roots of Valeriana dioscoridis. Their structures were elucidated by means of NMR spectroscopy and mass spectrometry. This is the first report on the phytochemical composition of the non-volatile constituents of V.

Antiproliferative and Antimicrobial Activities of Selected Bryophytes.

One-hundred and sixty-eight aqueous and organic extracts of 42 selected bryophyte species were screened in vitro for antiproliferative activity on a panel of human gynecological cancer cell lines containing HeLa (cervix epithelial adenocarcinoma), A2780 (ovarian carcinoma), and T47D (invasive ductal breast carcinoma) cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and for antibacterial activity on 11 strains using the disc-diffusion method. A total of 99 extracts derived from 41 species exerted ≥25% inhibition of proliferation of at least one of the cancer cell lines at 10 μg/mL. In the cases of , , , , , and , more than one extract was active in the antiproliferative assay, whereas the highest activity was observed in the case of .

Stereoselective Synthesis, Synthetic and Pharmacological Application of Monoterpene-Based 1,2,4- and 1,3,4-Oxadiazoles.

Stereoselective synthesis of monoterpene-based 1,2,4- and 1,3,4-oxadiazole derivatives was accomplished starting from α,β-unsaturated carboxylic acids, obtained by the oxidation of (-)-2-carene-3-aldehyde and commercially available (-)-myrtenal. 1,2,4-Oxadiazoles were prepared in two steps via the corresponding -acylamidoxime intermediates, which then underwent cyclisation induced by tetrabutylammonium fluoride (TBAF) under mild reaction conditions. Stereoselective dihydroxylation in highly stereospecific reactions with the OsO₄/NMO (-methylmorpholine -oxide) system produced α,β-dihydroxy 1,2,4-oxadiazoles.

Gymnopeptides A and B, Cyclic Octadecapeptides from the Mushroom Gymnopus fusipes.

Mycochemical study of the mushroom Gymnopus fusipes led to the discovery of two new cyclopeptides. The two compounds, named as gymnopeptides A and B, are unprecedented highly N-methylated cyclic octadecapeptides. Detailed spectroscopic studies, Marfey's analysis, and a preliminary molecular modeling study suggested that both are natural cyclic β hairpins.