Research progress of Pickering emulsion drug delivery systems / 药学学报

Pickering emulsion is a new type of emulsion which is stabilized by the adsorption of solid particles on the interface of emulsion droplets. In recent years, its applications in pharmacy have attracted more and more attention because of its higher resistance to coalescence and better safety than traditional surfactant emulsions. The Pickering emulsion was first used for topical administration to reduce skin irritation of surfactants and promote transdermal absorption of drugs. Recently, new oral and injectable Pickering emulsions have also been reported, which can promote oral absorption of insoluble drugs, improve stability of drugs, control drug release, targeted-delivery drugs, and serve as the carrier for novel immunological adjuvants. All these studies show Pickering emulsion a promising drug delivery system. However, its development in pharmacy is still in its infancy. There are many factors influencing the preparation of Pickering emulsions. But there is no systematic analysis of these factors up to now. In this review, we gave an overview of Pickering emulsions from their application in pharmaceutical field, preparation and evaluation, focusing on the effects of solid particles, oil phase, preparation technology and interaction of various factors on the fabrication of Pickering emulsions. The challenges and future directions of this exciting and rapidly expanding research area were further commented on, in order to provide reference for the in-depth study of Pickering emulsion drug delivery systems.

Preparation of poorly soluble drug curcumin nanocrystalline self-stabilized Pickering emulsion / 中草药

Objective: To prepare curcumin nanocrystalline (Cur-NC) self-stabilized Pickering emulsion (Cur-NCSPE). Methods: Cur-NCSPE was prepared by high pressure homogenization. The influences of homogenization pressure on Cur-NC size and drug content on Cur-NCSPE formation were studied. The morphology and structure of emulsion droplets were observed by optical microscope and scanning electron microscope. Furthermore, the stability and in vitro release properties of Cur-NCSPE were evaluated. Results: The particle size of Cur-NC was slightly changed when homogeneous pressure was greater than 100 MPa. With the increase of Cur, the amount of Cur-NC on the surface of oil droplets increases, and the particle size decreases. When the amount of drug added can completely cover the surface of oil droplets, increasing the amount of drug had little effect on the particle size. Cur-NCSPE was more stable than Cur-NC and Cur, and the in vitro release rate of Cur-NCSPE was significantly higher than that of Cur-NC and Cur coarse power. Conclusion: The Cur-NCSPE is prepared successfully, which is expected to provide a novel oral administration technology platform for the poorly soluble drugs.

Effect of solid particles in coptis decoction on intestinal absorption of berberine in situ / 中草药

Objective: To investigate the effects of particles in coptis (Coptidis Rhizoma)-decoction on the berberine absorption in intestine. Methods: The particles in copitis-decotion were separated by the high-speed centrifugation and weak-base anion-exchange resin. The characteristics of berberine absorption in intestine were evaluated by the in situ intestinal perfusion in rats. Results: Although each segment of small intestine exhibited obvious berberine absorption, the jejunum exhibited the highest absorption rate constant (Ka) of (3.587 9 ± 0.005 2) × 10-4/s and effective permeability coefficient (Peff) of (4.529 4 ± 0.009 7) × 10-5 cm/s. Particles P1 and P2, with similar size of (272.7 ± 25.2) and (264.8 ± 21.4) nm and different surface potential of (-6.85 ± 0.16) and (-18.20 ± 0.71) mV, were obtained from the copitis-decotion. Particle P1 could significantly improve the berberine absorption in intestine, with Ka of (5.853 6 ± 0.970 1) × 10-4/s and Peff of (8.082 4 ± 1.004 2) × 10-5 cm/s. Conclusion: Particles in coptis-decotion can improve the berberine absorption in intestine. The surface potential of the particles may be responsible for the improvement of berberine absorption.

The application research progress of pickering emulsion in pharmaceutical field / 中国药学杂志

Pickering emulsions stabilized by solid microparticles, having the advantages of strong interfacial stability, non-toxicity and eco-friendliness compared with the traditional surfactant-stabilized emulsions, have been the focus of considerable researches in recent years. In this review, the application studies on Pickering emulsions were summarized from the following aspects:the stabilization theory about Pickering emulsions, solid microparticles used in Pickering emulsions, the applications of Pickering emulsions in pharmaceutical field and the new Pickering emulsion stabilized by drug nanocrystalline itself. These research progress would promote and expand the application of Pickering emulsions in pharmaceutical field.