Peipei Zhang

Preparation and in vitro release of buccal tablets of naringenin-loaded MPEG-PCL nanoparticles

Naringenin-loaded monomethoxy poly(ethylene glycol)-poly (e-caprolactone) (MPEG-PCL) nanoparticles (NARNP) and their formulation into buccal tablets using mucoadhesive polymers were developed to improve the solubility of naringenin and to treat oral inflammatory and ulcerative diseases. In our work, physicochemical characterizations of NARNP including particle size, zeta potential, transmission electron microscopy (TEM), differential scanning calorimetery, Fourier transform infrared spectroscopy and in vitro release were studied. NARNP buccal tablets and control buccal tablets containing MPEG-PCL copolymers and mannitol respectively were prepared and they were evaluated by weight variation, hardness, friability and in vitro release. NARNP had a small size (<100 nm), good encapsulation efficiency (95.26 ± 1.15%), and high drug loading (9.95 ± 0.15%). The lyophilized powder of NARNP showed good stability and re-solubility. For the in vitro release study of buccal tablets, Drug dissolution rate was investigated by the USP I method. To simulate in vivo conditions of the oral cavity, a new dissolution test apparatus was designed for assessment of drug release. Compared to control groups, buccal tablets containing NARNP showed more rapid and complete drug release (more than 80%) over 12 h using two dissolution test apparatuses. NARNP incorporated into buccal tablets effectively improved the release of naringenin. With desirable drug release and release time (12 h), NARNP buccal tablets may be an efficient vehicle for treatment of oral inflammatory and ulcerative diseases.

Influence of CYP2C19 loss‐of‐function variants on the metabolism of clopidogrel in patients from north‐western China

Variation of the cytochrome P450 2C19 gene coding for the CYP2C19 enzyme has been reported to be associated with clopidogrel response variability. The activity of the CYP2C19 enzyme is genetically influenced by polymorphisms of its gene.

Preparation, characterization, and evaluation of amphotericin B-loaded MPEG-PCL-g-PEI micelles for local treatment of oral Candida albicans

Fatal Candida albicans infections in the mucosal system can occur in association with immune-compromised diseases and dysbacteriosis. Currently, amphotericin B (AmB) is considered to be the most effective antibiotic in the treatment of C. albicans infections, but its clinical application is limited by side effects and poor bioavailability. In order to use AmB in the local treatment of oral C. albicans infections, AmB/MPEG-PCL-g-PEI (monomethoxy poly(ethylene glycol)-poly(epsilon-caprolactone)-graft-polyethylenimine, MPP) micelles were prepared. A series of characterizations were performed. The micelles allowed a sustained in vitro release in both normal oral conditions (pH 6.8) and C. albicans infection conditions (pH 5.8). Then, buccal tablets containing freeze-dried powder of AmB/MPP micelles were produced by direct compression process and evaluated as regards to weight variation, hardness, and friability. In vitro drug release of the buccal tablets was measured in both the United States Pharmacopeia dissolution apparatus and the dissolution rate test apparatus, which was previously designed for simulating in vivo conditions of the oral cavity. The buccal tablets could sustainably release within 8 h and meet the antifungal requirements. Regarding safety assessment of AmB/MPP micelles, in vivo histopathological data showed no irritation toward buccal mucosa of the rats in both optical microscopy and ultrastructure observation of the tissues. MTT experiment proved that AmB/MPP micelles reduced the cytotoxicity of AmB. The micelles delivered through the gastrointestinal route were also found to be non-systemic toxicity by liquid chromatography-mass spectrometry analysis. Furthermore, the antifungal action of AmB/MPP micelles was evaluated. Although AmB/MPP had no obvious improvement as compared to AmB alone in the antifungal effect on planktonic C. albicans, the micelles significantly enhanced the antifungal activity against the biofilm state of C. albicans. Thus, it was concluded that AmB/MPP micelles represent a promising novel drug delivery system for the local treatment of oral C. albicans infections.

Determination and correlation of the solubility of myricetin in ethanol and water mixtures from 288.15 to 323.15K

ABSTRACT The solubility of myricetin (MY) is very important in regard to its extraction and purification, which was performed by an equilibrium method in the binary solvent system of ethanol and water in the temperature range 288.15 ~ 323.15 K and was determined by ultraviolet (UV-Vis) spectrophotometry at 375 nm. The experimental solubility values were correlated by four mathematical equations: a simplified universal equation (ideal model), modified Apelblat equation, equation and Jouyban–Acree equation. The modified Apelblat model is more suitable for predicting the solubility data of MY in the binary solvent system of ethanol and water at this experimental temperature range. The dissolution enthalpy and entropy of MY were evaluated by the Van’t Hoff and Gibbs−Helmholtz equations. The results illustrate that the dissolution process in binary system solvent mixtures is strongly dependent on solvent composition and temperature, and this process was endothermic and entropy driven. GRAPHICAL ABSTRACT

Kinetics and modeling for extraction of chrysin from Oroxylum indicum seeds

Research on extraction of chrysin is crucial for theoretical purposes and for food industrial bioprocesses. Optimization and kinetics of chrysin extraction from seeds of Oroxylum indicum (L.) Vent. were analyzed using agitated solid-liquid extractions with ethanol and water mixtures. The influence of extraction process parameters was investigated. Optimized conditions for chrysin extraction were a 0.2 mole fraction of ethanol as an extraction solvent, a temperature of 318 K, an agitation speed 1,400 rpm, and a solid to solvent ratio of 1:30. The extraction kinetic behavior of chrysin followed first order kinetics. The kinetic expression developed by Spiro and Siddique was used and the model was in agreement with experimental results. The diffusion coefficient ranged from 1.38×10−11 to 19.43×10−11 m2·s−1 and the activation energy for extraction kinetics was 21.85 kJ·mol−1.

Preparation, characterization and toxicity evaluation of amphotericin B loaded MPEG-PCL micelles and its application for buccal tablets

Oral candidiasis or thrush is a fungal infection due to Candida albicans, causing discomfort in areas inside mouth or tongue. The clinical application of antifungal reagent amphotericin B (AMB), which is believed to offer a better treatment for oral candidiasis, is greatly compromised by its toxicities (mainly nephrotoxicity) and poor solubility. In order to overcome these issues, we characterized AMB-loaded MPEG-PCL micelles in vitro and in vivo. In addition, the antifungal activities of AMB/MPEG-PCL micelles-loaded buccal tablet were also evaluated in vitro. We found that micelles system could significantly improve the solubility of AMB yet reduce the overall toxicity, while the buccal tablet system is capable to suppress C. albicans biofilm formation. Furthermore, the toxicity of the buccal tablet system is also reduced compared with other standard preparations. Therefore, the prepared tablet with AMB-loaded MPEG-PCL micelles as oral topical preparations has the potential to improve current treatment of superficial oral C. albicans infections.