Development of metformin hydrochloride loaded dissolving tablets with novel carboxymethylcellulose/poly-l-lysine/TPP complex.

Natural polymers like polysaccharides, polypeptides and their derivatives are broadly applied in drug delivery due to excellent biocompatibility and biodegradability. In this study, the dissolving tablets, formed with carboxymethylcellulose/poly-l-lysine/tripolyphosphate (CMC/PLL/TPP) complex, were prepared using metformin hydrochloride (MetHCl) as model drug. Confocal laser scanning microscopy observation manifested that FITC-labeled PLL interacted with CMC and formed a uniform interior microstructure. Scanning electron microscope images showed the drug-loaded tablets had well-formed shapes with smooth surfaces. MetHCl embedded interior the microstructures of the tablets and represented in a crystal form. Thermo-gravimetric analysis and differential scanning calorimetry indicated that the drug-loaded tablets had stable thermal properties with less moisture content (3.52%). Fourier transform infrared spectrometer confirmed that the CMC/PLL/TPP complex was fabricated via the electrostatic interactions between -NH3+, -COO- and -[P2O54-]- groups. The drug-loaded tablets had a high drug loading efficiency of 85.76% and drug encapsulation efficiency of 81.47%, and a shorter wetting time of 2.16 min in SSF (pH 6.8) and lower swelling ratio of 233.34%. The drug loaded in the samples could be released completely within 10 min in simulated saliva fluid (SSF pH 6.8), indicating a rapid drug release and dissolving profile in the environment, which could be developed for dissolving tablets.

Bioactive 30-noroleanane triterpenes from the pericarps of Akebia trifoliata.

Two new 30-noroleanane triterpenes, 2α,3ß,20α-trihydroxy-30-norolean-12-en-28-oic acid (1), 2α,3ß-dihydroxy-23-oxo-30-norolean-12,20(29)-dien-28-oic acid (2), were isolated from the pericarps of Akebia trifoliata, together with four known ones, 3ß-akebonoic acid (3), 2α,3ß-dihydroxy-30-noroleana-12,20(29)-dien-28-oic acid (4), 3α-akebonoic acid (5) and quinatic acid (6). Their structures were established on the basis of detailed spectroscopic analysis, and they were all isolated from the pericarps of A. trifoliata for the first time. Compounds 3-6 showed in vitro bacteriostatic activity against four assayed Gram-positive bacterial strains. In particular 3 showed antibacterial activity toward MRSA with a MIC value 25 µg/mL, which was more potent than kanamycin (MIC 125 µg/mL). No compounds showed antibacterial activity toward the three Gram-negative bacteria tested. Compounds 4 and 5 showed interesting in vitro growth inhibitory activity against human tumor A549 and HeLa cell lines, with IC50 values ranging from 8.8 and 5.6 µM, respectively. Compounds 1, 2, 5 and 6 were further revealed to show significant in vitro α-glucosidase inhibitory activity with IC50 values from 0.035 to 0.367 mM, which were more potent than the reference compound acarbose (IC50 0.409 mM).

Bioactive quinic acid derivatives from Ageratina adenophora.

A novel quinic acid derivative, 5-O-trans-o-coumaroylquinic acid methyl ester (1), together with three known ones, chlorogenic acid methyl ester (2), macranthoin F (3) and macranthoin G (4), were isolated from the aerial parts of the invasive plant Ageratina adenophora (Spreng.). The structure of new compound 1 was elucidated on the basis of extensive spectroscopic analysis, including 1D- and 2D-NMR techniques. Compounds 2-4 were isolated from plant A. adenophora for the first time. All the compounds showed in vitro antibacterial activity toward five assayed bacterial strains, especially 3 and 4, which showed in vitro antibacterial activity against Salmonella enterica with MIC values of 7.4 and 14.7 µM, respectively. Compound 1 was further found to display in vitro anti-fungal activity against spore germination of Magnaporthe grisea with an IC50 value 542.3 µM. These four compounds were also tested for their antioxidant activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radical.