STRUCTURE AND BIOLOGICAL ACTIVITY OF LIPIARMYCIN
Actinoplanes deccanensis ATCC21983, the producer of antibiotics lipiarmycin A3 and A4, furnished also a related antibiotic designated lipiarmycin B, active against Gram-positive bacteria, including anaerobes, and against Neisseria. The structures of the two major components, B3 and B4, were elucidated from their physico-chemical properties, XHand 13C NMRspectra and fast atom bombardmentmass spectra data in comparison with lipiarmycins A3andA4.
Structure elucidation of the macrocyclic antibiotic lipiarmycin
By a combination of chemical degradations and 1H and 13C n.m.r. studies, the structure of the antibiotic lipiarmycin, produced by Actinoplanes deccanensis, has been elucidated. The molecule contains two glycosyl moieties, namely 2-O-methyl-4-O-homodichloro-orsellinate-β-D-rhamnose and 4-O-isobutyrate-5-methyl-β-rhamnose, attached to a 18-membered unsaturated lactone ring.
Rational Design, Synthesis and Evaluation of γ-CD-Containing Cross-Linked Polyvinyl Alcohol Hydrogel as a Prednisone Delivery Platform
This study describes the in-silico rational design, synthesis and evaluation of cross-linked polyvinyl alcohol hydrogels containing γ-cyclodextrin (γ-CDHSAs) as platforms for the sustained release of prednisone (PDN). Through in-silico studies using semi-empirical quantum mechanical calculations, the effectiveness of 20 dicarboxylic acids to generate a specific cross-linked hydrogel capable of supporting different amounts of γ-cyclodextrin (γ-CD) was evaluated. According to the interaction energies calculated with the in-silico studies, the hydrogel made from PVA cross-linked with succinic acids (SA) was shown to be the best candidate for containing γ-CD. Later, molecular dynamics simulation studies were performed in order to evaluate the intermolecular interactions between PDN and three cross-linked hydrogel formulations with different proportions of γ-CD (2.44%, 4.76% and 9.1%). These three cross-linked hydrogels were synthesized and characterized. The loading and the subsequent release of PDN from the hydrogels were investigated. The in-silico and experimental results showed that the interaction between PDN and γ-CDHSA was mainly produced with the γ-CDs linked to the hydrogels. Thus, the unique structures and properties of γ-CDHSA demonstrated an interesting multiphasic profile that could be utilized as a promising drug carrier for controlled, sustained and localized release of PDN.