Chitosan oligosaccharide (COS): An overview.

The frequently studied polysaccharide, chitosan oligosaccharide/chitooligosaccharide (COS) is the major degradation product of chitosan/chitin via chemical hydrolysis or enzymatic degradation involving deacetylation and depolymerization processes. Innumerable studies have revealed in the recent decade that COS has various promising biomedical implications in the past analysis, current developments and potential applications in a biomedical, pharmaceutical and agricultural sector. Innovations into COS derivatization has broadened its application in cosmeceutical and nutraceutical productions as well as in water treatment and environmental safety. In relation to its parent biomaterials and other available polysaccharides, COS has low molecular weight (Mw), higher degree of deacetylation (DD), higher degree of polymerization (DP), less viscous and complete water solubility, which endowed it with significant biological properties like antimicrobial, antioxidant, anti-inflammatory and antihypertensive, as well as drug/DNA delivery ability. In addition, it is also revealed to exhibit antidiabetic, anti-obesity, anti-HIV-1, anti-Alzheimer's disease, hypocholesterolemic, calcium absorption and hemostatic effects. Furthermore, COS is shown to have higher cellular transduction and completely absorbable via intestinal epithelium due to its cationic sphere exposed on the more exposed shorter N-glucosamine (N-Glc) units. This paper narrates the recent developments in COS biomedical applications while paying considerable attention to its physicochemical properties and its chemical composition. Its pharmacokinetic aspects are also briefly discussed while highlighting potential overdose or lethal dosing. In addition, due to its multiple NGlc unit composition and vulnerability to degradation, its safety is given significant attention. Finally, a suggestion is made for extensive study on COS anti-HIV effects with well-refined batches.

Liposomal doxorubicin loaded PLGA-PEG-PLGA based thermogel for sustained local drug delivery for the treatment of breast cancer.

The aim of this research is to utilize a hybrid system of liposomal doxorubicin (DOX-Lip) loaded thermogel (DOX-Lip-Gel) to realize the steady sustained delivery of doxorubicin (DOX), a small hydrophilic drug, for the treatment of breast cancer locally. Herein, liposomal doxorubicin was prepared via the traditional film dispersion method with the particle size of 75 nm and drug entrapment efficiency of 86%. And, the triblock copolymer of poly (D, L-lactide-co-glycolide)-b-poly (ethylene glycol)-b-poly (D, L-lactide -co-glycolide) (PLGA-PEG-PLGA) was synthesized via ring-opening polymerization to prepare the thermosensitive hydrogel through dissolving the polymers in DOX-Lip solution. The liposome loaded hydrogel was in a sol state at room temperature and converted into the gel state at body temperature and would degrade gradually during the time in vivo. The drug release of DOX out of DOX-Lip-Gel could be in a steady sustained manner up to 11 days without significant burst release as compared to that of DOX-loaded hydrogel (DOX-Gel). An orthotopic breast cancer model was adopted to evaluate the in vivo antitumor efficacy. And, the results revealed DOX-Lip-Gel had better antitumor efficiency as well as lower side effects.