Microencapsulation of human insulin DEAE-dextran complex and the complex in liposomes by the emulsion non-solvent addition method

Thermoresponsive nanogels based on polyelectrolyte complexes between polycations and functionalized hyaluronic acid

A novel kind of thermoresponsive polyelectrolyte complex-based nanogels (PEC-NGs) was elaborated by mixing hyaluronic acid (HA) functionalized with Jeffamine® M-2005 (M2005, a thermoresponsive amine-terminated polyether) and diethylaminoethyl dextran (DEAE-D) or poly-l-lysine (PLL) in water. The presence of M2005 grafts led to PEC-NGs with larger particle size, lower net surface charge and thermoresponsiveness, namely shrinkage with increasing hydrophobicity at higher temperature. Both M2005 grafts and replacing DEAE-D with PLL as polycation allowed PEC-NGs to have higher stability against salinity and better encapsulation of curcumin, most probably through intraparticle hydrophobic interactions, whereas interparticle hydrophobic interactions may facilitate particle aggregation over time. Curcumin encapsulation can be optimized by applying higher temperature during the complexation. Enzymatic degradability of PEC-NGs was also verified through particle size evolution in the presence of hyaluronidase. These results provide new insights into the physicochemical aspect of such systems as promising nanocarriers for drug delivery.

Quantification of BSA-loaded chitosan/oligonucleotide nanoparticles using reverse-phase high-performance liquid chromatography

Therapeutic proteins are administered subcutaneously because of their instability in the gastrointestinal tract. Current research suggests that polymeric-based nanoparticles, microparticles and liposomes are ideal nanocarriers to encapsulate proteins for disease management. In order to develop a successful drug delivery system, it is crucial to determine drug release profile and stability. However, the non-active excipients in polymeric formulations can influence the quantification of proteins in analytical techniques. This study investigated the effect of nine common polymers on quantification of bovine serum albumin (BSA) using RP-HPLC method. The technique offers advantages such as short analytical time, high accuracy and selectivity. In the meantime, the technique can be employed to separate proteins including BSA, insulin and pigment epithelium-derived factor (PEDF). Furthermore, the RP-HPLC method was applied to quantify the drug release pattern of a novel BSA-loaded nanoparticulate formulation in simulated gastric and intestinal fluids. The nanoparticles were formulated by natural polymer (chitosan) and oligonucleotide (Dz13Scr) using complex coacervation. The prepared particles were found to have small size (337.87 nm), low polydispersity index (0.338) and be positively charged (10.23 mV). The in vitro drug release patterns were characterised using the validated RP-HPLC method over 12 h. Graphical abstract ᅟ.

Lipoinsulin encapsulated alginate-chitosan capsules: intestinal delivery in diabetic rats

An oral formulation based on liposome encapsulated alginate-chitosan gel capsules was developed for insulin delivery for the treatment of diabetes. Liposome encapsulation helped to increase the encapsulation efficiency of insulin in alginate-chitosan capsules. This formulation delivers insulin in the neutral environment of the intestine, by-passing the acidic media in the stomach, with increased drug absorption and bioavailability. Oral administration of this formulation was found to reduce blood glucose levels when tested in diabetic rats.