The insulin long-acting chitosan - Polyethyleneimine nanoparticles to treat the type 2 diabetes mellitus and prevent the associated complications.

Type 2 diabetes mellitus (T2DM) is a complex metabolic disorder, which is ultimately treated by the insulin (INS). However, the subcutaneous (s. c.) injection of insulin solution faces the problems of pain and unsatisfactory patient compliance. In this study, the long-acting formulations of insulin are propsed to treat the T2DM and prevent the associated complications. The chitosan (CS) and/or branched polyethyleneimine (bPEI) nanoparticles (bPEI-INS NPs, CS-bPEI-INS NPs) were constructed to load insulin. The long -acting nanoparticles successfully achieved the sustained release of the INS in vitro and in vivo. After s. c. administration, the CS-bPEI-INS NPs greatly improved the INS bioavailability. As a result, the CS-bPEI-INS NPs produced sustained glucose-lowering effects, promising short-term and long-term hypoglycemic efficacy in the T2DM model. Furthermore, the treatment of the CS-bPEI-INS NPs greatly protected the islet in the pancreas and prevented the associated complications of the T2DM, such as cardiac fibrosis in the myocardial interstitium and the perivascular area. In a word, the CS-bPEI-INS NPs was an encouraging long-acting formulation of insulin and had great potential in the treatment of T2DM.

The use of amphiphilic copolymer in the solid dispersion formulation of nimodipine to inhibit drug crystallization in the release media: Combining nano-drug delivery system with solid preparations.

Solid dispersion is a widely used method to improve the dissolution and oral bioavailability of water-insoluble drugs. However, due to the strong hydrophobicity, the drug crystallization in the release media after drug dissolution and the resulted decreased drug absorption retards the use of solid dispersions. It is widely known that the amphiphilic copolymer can encapsulate the hydrophobic compounds and help form stable nano-dispersions in water. Inspired by this, we tried to formulate the solid dispersion of nimodipine by using amphipathic copolymer as one of the carriers. Concerning the solid dispersions, there are many important points involved in these formulations, such as the miscibility between the drug and the carriers, the storage stability of solid dispersions, the dissolution enhancement and so on. In this study, a systemic method is proposed. In details, the supersaturation test and the glass transition temperature (Tg) measurement to predict the crystallization inhibition, the ratios of different components and the storage stability, the interactions among the components were investigated in detail by nuclear magnetic resonance (1H NMR) and isothermal titration calorimetry (ITC) and, the final dissolution and oral bioavailability enhancement. It was found that the amphiphilic copolymer used in the solid dispersion encouraged the formation the drug loading micelles in the release media and, finally, the problem of drug crystallization in the dissolution process was successfully solved.