Metformin hydrochloride sustained release biopolymeric system composed by PLLA‐CMC microparticles

Robust Superhydrophobic Films Based on an Eco-Friendly Poly(l-lactic acid)/Cellulose Composite with Controllable Water Adhesion

Poly(l-lactic acid) (PLLA) featuring desirable biodegradability and biocompatibility has been recognized as one of the promising eco-friendly biomaterials. However, low crystallization and poor mechanical and chemical performances dramatically hamper its practical application. In this work, we report that functionalized cellulose/PLLA composite superhydrophobic stereocomplex films with controllable water adhesion and protein adsorption can be fabricated by a facile approach for the first time. First, cellulose is surface-modified by means of two silanization modification methods. Then, superhydrophobic cellulose/PLLA composite films are prepared through a solvent-evaporation-induced phase separation method. The two cellulose/PLLA composite films exhibit extreme water repellency but tunable water adhesion from sticky to slippery. The protein adsorption capacity of the cellulose/PLLA composite films can also be regulated. In addition, the stereocomplexation of the composite film provides excellent mechanical properties with an elongation at break of 22.36%, which is 237.8% higher than that of a pure PLLA film, which is more suitable for biomaterials. Furthermore, good biodegradability of the PLLA composite films in nature enables the bio-based composites as alternative materials to replace conventional petroleum-based polymers. The superhydrophobic films have also been demonstrated for many applications, including slippery surfaces, liquid transportation without loss, and antifouling.

Formulation and Evaluation of Xanthan Gum Microspheres for the Sustained Release of Metformin Hydrochloride

This work aimed to formulate xanthan gum microspheres for the encapsulation of metformin hydrochloride, according to the process of ionotropic gelation. The obtained microparticles, based on various fractions of xanthan gum (0.5-1.25), were subjected to different physico-chemical tests and a drug release study. Microspheres with an average size varying between 110.96 μm and 208.27 μm were obtained. Encapsulation efficiency reached 93.11% at a 1.25% biopolymer concentration. The swelling study showed a swelling rate reaching 29.8% in the gastric medium (pH 1.2) and 360% in the intestinal medium (pH 6.8). The drug release studies showed complete metformin hydrochloride release from the beads, especially those prepared from xanthan gum at the concentration of 1.25%, in intestinal medium at 90.00% after 6 h. However, limited and insignificant drug release was observed within the gastric medium (32.50%). The dissolution profiles showed sustained release kinetics.

The Antidiabetic Activities of Neocryptotanshinone: Screened by Molecular Docking and Related to the Modulation of PTP1B

The aim of this study was to provide a practical experimental basis for the development of Neocryptotanshinone (NCTS) as an effective hypoglycemic drug and a theoretical method for the rapid screening of natural compounds with hypoglycemic effects. Molecular docking was used to screen the most suitable ligand. Hematoxylin and eosin, immunohistochemical staining, enzyme-linked immunosorbent assay and Western Blotting approved the hypoglycemic effect of NCTS. According to the free energy of binding, among 180 active compounds from the Traditional Chinese Medicine Integrated Database, NCTS was finally chose for investigation its hypoglycemic effects. In db/db mice, NCTS significantly reduced body weight and plasma glucose, improved glucose tolerance and levels of fasting plasma glucose and glycated hemoglobin A1c, and decreased insulin resistance after six-week administration. NCTS restored the pathological state in the liver of db/db mice and significantly decreased protein tyrosine phosphatase 1B (PTP1B) expression in the liver and muscle of db/db mice, which is related to the regulatory effect of NCTS on insulin receptor substrate 1. In conclusion, we successfully explored the hypoglycemic effect of NCTS in db/db mice via regulating the expression of PTP1B.

The Nanostructure of Polymer-Active Principle Microparticles Produced by Supercritical CO2 Assisted Processing

Traditional and supercritical CO₂ assisted processes are frequently used to produce microparticles formed by a biopolymer containing an active principle to improve the bioavailability of the active principle. However, information about the internal organization of these microparticles is still scarce. In this work, a suspension of dextran + Fe₃O₄ nanoparticles (model system) and a solution of polyvinylpyrrolidone (PVP) + curcumin were used to produce spherical microparticles by supercritical CO₂ processing. Periodic dynamic light scattering measurements were used to analyze the evolution of the microparticles dissolution, size, and size distribution of the guest active principle in the polymeric matrix. It was found that curcumin was dispersed in the form of nanoparticles in the PVP microparticles, whose size largely depended on its relative concentration. These results were validated by transmission electron microscopy and scanning electron microscopy of the PVP microparticles and curcumin nanoparticles, before and after the dissolution tests.

The Effect of Drug Heterogeneous Distributions within Core-Sheath Nanostructures on Its Sustained Release Profiles

The sustained release of a water-soluble drug is always a key and important issue in pharmaceutics. In this study, using cellulose acetate (CA) as a biomacromolecular matrix, core-sheath nanofibers were developed for providing a sustained release of a model drug-metformin hydrochloride (MET). The core-sheath nanofibers were fabricated using modified tri-axial electrospinning, in which a detachable homemade spinneret was explored. A process-nanostructure-performance relationship was demonstrated through a series of characterizations. The prepared nanofibers F2 could release 95% of the loaded MET through a time period of 23.4 h and had no initial burst effect. The successful sustained release performances of MET can be attributed to the following factors: (1) the reasonable application of insoluble CA as the filament-forming carrier, which determined that the drug was released through a diffusion manner; (2) the core-sheath nanostructure provided the possibility of both encapsulating the drug completely and realizing the heterogeneous distributions of MET in the nanofibers with a higher drug load core than the sheath; (3) the thickness of the sheath sections were able to be exploited for further manipulating a better drug extended release performance. The mechanisms for manipulating the drug sustained release behaviors are proposed. The present proof-of-concept protocols can pave a new way to develop many novel biomolecule-based nanostructures for extending the release of water-soluble drugs.