Modern Approaches in Wounds Management.

Wound management represents a well-known continuous challenge and concern of the global healthcare systems worldwide. The challenge is on the one hand related to the accurate diagnosis, and on the other hand to establishing an effective treatment plan and choosing appropriate wound care products in order to maximize the healing outcome and minimize the financial cost. The market of wound dressings is a dynamic field which grows and evolves continuously as a result of extensive research on developing versatile formulations with innovative properties. Hydrogels are one of the most attractive wound care products which, in many aspects, are considered ideal for wound treatment and are widely exploited for extension of their advantages in healing process. Smart hydrogels (SHs) offer the opportunities of the modulation physico-chemical properties of hydrogels in response to external stimuli (light, pressure, pH variations, magnetic/electric field, etc.) in order to achieve innovative behavior of their three-dimensional matrix (gel-sol transitions, self-healing and self-adapting abilities, controlled release of drugs). The SHs response to different triggers depends on their composition, cross-linking method, and manufacturing process approach. Both native or functionalized natural and synthetic polymers may be used to develop stimuli-responsive matrices, while the mandatory characteristics of hydrogels (biocompatibility, water permeability, bioadhesion) are preserved. In this review, we briefly present the physiopathology and healing mechanisms of chronic wounds, as well as current therapeutic approaches. The rational of using traditional hydrogels and SHs in wound healing, as well as the current research directions for developing SHs with innovative features, are addressed and discussed along with their limitations and perspectives in industrial-scale manufacturing.

Recent Biomedical Approaches for Chitosan Based Materials as Drug Delivery Nanocarriers.

In recent decades, drug delivery systems (DDSs) based on nanotechnology have been attracting substantial interest in the pharmaceutical field, especially those developed based on natural polymers such as chitosan, cellulose, starch, collagen, gelatin, alginate and elastin. Nanomaterials based on chitosan (CS) or chitosan derivatives are broadly investigated as promising nanocarriers due to their biodegradability, good biocompatibility, non-toxicity, low immunogenicity, great versatility and beneficial biological effects. CS, either alone or as composites, are suitable substrates in the fabrication of different types of products like hydrogels, membranes, beads, porous foams, nanoparticles, in-situ gel, microparticles, sponges and nanofibers/scaffolds. Currently, the CS based nanocarriers are intensely studied as controlled and targeted drug release systems for different drugs (anti-inflammatory, antibiotic, anticancer etc.) as well as for proteins/peptides, growth factors, vaccines, small DNA (DNAs) and short interfering RNA (siRNA). This review targets the latest biomedical approaches for CS based nanocarriers such as nanoparticles (NPs) nanofibers (NFs), nanogels (NGs) and chitosan coated liposomes (LPs) and their potential applications for medical and pharmaceutical fields. The advantages and challenges of reviewed CS based nanocarriers for different routes of administration (oral, transmucosal, pulmonary and transdermal) with reference to classical formulations are also emphasized.

The safety profile of new antidiabetic xanthine derivatives and their chitosan based formulations.

The safety profile of new antidiabetic xanthine derivatives with thiazolidine­4­one scaffold (6, 7) and their new chitosan based formulations (CS-6, CS-7), administrated to diabetic rats, have been evaluated in terms of biochemical markers of liver and kidney function as well as of hematological markers. The effect on lipid profile and clinic parameters (body weight, food and water intake) has been also evaluated. The treatment of diabetic rats with xanthine derivatives (6, 7) and chitosan based formulations (CS-6, CS-7) was associated with lower liver enzymes (AST, ALT, LDH) and bilirubin (direct, total) values compared to the non-treated diabetic rats, that means the tested derivatives/formulations have improved the liver function injured in diabetes mellitus conditions. Also the kidney biochemical markers (creatinine, uric acid, urea) were significantly decreased in diabetic rats treated with 6, 7 and chitosan microparticles (CS-6, CS-7). The values of biochemical markers of liver and kidney functions were even better than the values recorded for pioglitazone, used as standard antidiabetic drug. The improving effect on kidney function was proved by the histopathological study. Moreover, the xanthine derivatives and their chitosan based formulation were associated with improved hematological markers compared to the non-treated diabetic rats which mean the improving of the hemorheological state. These results support the safety profile of new xanthine derivatives with thiazolidine­4­one scaffold (6, 7) and their new chitosan based formulations (CS-6, CS-7) and their potential applications for the treatment of diabetes mellitus syndrome.

Synthesis and biological evaluation of the new 1,3-dimethylxanthine derivatives with thiazolidine-4-one scaffold.

BACKGROUND: The xanthine structure has proved to be an important scaffold in the process of developing a wide variety of biologically active molecules such as bronchodilator, hypoglycemiant, anticancer and anti-inflammatory agents. It is known that hyperglycemia generates reactive oxygen species which are involved in the progression of diabetes mellitus and its complications. Therefore, the development of new compounds with antioxidant activity could be an important therapeutic strategy against this metabolic syndrome. RESULTS: New thiazolidine-4-one derivatives with xanthine structure have been synthetized as potential antidiabetic drugs. The structure of the synthesized compounds was confirmed by using spectral methods (FT-IR, 1H-NMR, 13C-NMR, 19F-NMR, HRMS). Their antioxidant activity was evaluated using in vitro assays: DPPH and ABTS radical scavenging ability and phosphomolybdenum reducing antioxidant power assay. The developed compounds showed improved antioxidant effects in comparison to the parent compound, theophylline. In the case of both series, the intermediate (5a-k) and final compounds (6a-k), the aromatic substitution, especially in para position with halogens (fluoro, chloro), methyl and methoxy groups, was associated with an increase of the antioxidant effects. CONCLUSIONS: For several thiazolidine-4-one derivatives the antioxidant effect of was superior to that of their corresponding hydrazone derivatives. The most active compound was 6f which registered the highest radical scavenging activity.Graphical abstractDesign and synthesis of new thiazolidine-4-one derivatives.

Development, optimization and biological evaluation of chitosan scaffold formulations of new xanthine derivatives for treatment of type-2 diabetes mellitus.

New xanthine derivatives as antidiabetic agents were synthesized and new chitosan formulations have been developed in order to improve their biological and pharmacokinetic profile. Their physicochemical properties in terms of particle size, morphology, swelling degree, crystalline state, the loading efficiency as well as in vitro release and biodegradation rate were evaluated. According to the results the optimized formulations have a high drug loading efficiency (more than 70%), small particle size, a good release profile in the simulated biological fluids (the percentage of cumulative release being more than 55%) and improved biodegradation rate in reference with chitosan microparticles. The presence of xanthine derivatives (6, 7) in chitosan microparticles was demonstrated by means of FTIR analysis. The X-ray diffraction (XRD) proved that xanthine derivatives present a crystalline state. The biological evaluation assays confirmed the antioxidant and antidiabetic effects of the xanthine derivatives (6, 7) and their chitosan formulations (CS-6, CS-7). Xanthine derivative 6 showed a high antiradical scavenging effect (DPPH remaining=41.78%). It also reduced the glucose blood level with 59.30% and recorded level of glycosylated hemoglobin was 4.53%. The effect of its chitosan formulation (CS-6) on the level of blood glucose (114.5mg/dl) was even more intense than the one recorded by pioglitazone (148.5mg/dl) when used as standard antidiabetic drug. These results demonstrated the potential application of xanthine derivative 6 and its chitosan formulation (CS-6) in the treatment of the diabetes mellitus syndrome.

The synthesis and the biological evaluation of new thiazolidin-4-one derivatives containing a xanthine moiety.

Starting from theophylline (1,3-dimethylxanthine) new thiazolidin-4-one derivatives 7a1₋7, 7b1₋7 have been synthesized as potential antidiabetic drugs. The structure of the new derivatives was confirmed using spectral methods (FT-IR, ¹H-NMR, ¹³C-NMR). The in vitro antioxidant potential of the synthesized compounds was evaluated according to the ferric reducing power, the total antioxidant activity and the DPPH and ABTS radical scavenging assays. Reactive oxygen species (ROS) and free radicals are considered to be implicated in a variety of pathological events, such as diabetes mellitus and its micro- and macrovascular complications. The results of chemical modulation of the thiazolidin-4-one intermediaries 6a, 6b through condensation with several aromatic aldehydes is the improvement of the antioxidant effect. All benzylidenethiazolidin-4-one derivatives 7a1₋7, 7b1₋7 are more active than their parent thiazolidin-4-ones. The most active compounds are the ones obtained by reaction of condensation with 4-hydroxybenzaldehyde (compounds 7a5, 7a6), 4-dimethylaminobenzaldehyde (compounds 7a6, 7b6) and 2-nitrobenzaldehyde (compounds 7a7, 7b7).

[Incretin modulators, a new perspective in diabetes mellitus treatment]. / Modulatorii incretinelor, o noua perspectiva în tratamentul diabetului zaharat.

AIM: The study was designed to present the modern therapy used for the treatment of type 2 diabetes mellitus (T2DM). MATERIAL AND METHODS: Diabetes mellitus and the pharmacological and the pharmacokinetic characteristics of the incretins and of the incretin modulators are presented. RESULTS: Diabetes mellitus is a chronic metabolic disorder, which is considered to be a major health issue all over the world. World Health Organization indicates that world-wide almost 3 million deaths per year are caused by diabetes and 1,5 million new cases are diagnosed annually, T2DM representing approximately 90-95% of the diagnosed cases. This form of diabetes mellitus is characterized by several path physiological defects including insulin resistance at peripheral target tissues, excess hepatic glucose production and progressive pancreatic beta cell dysfunction. The newest direction in the treatment of T2DM mellitus is the incretin modulators. The incretins (GLP-1--glucagon-like-peptide-1 and GIP--glucose-dependent insulin tropic peptide), are natural hormones that contribute to glucose homeostasis by acting on the pancreas, gastrointestinal tract, muscle and brain tissue. After secretion, GLP-1 and GIP are immediately metabolized by dipeptidyl peptidase IV enzyme (DPP IV), which limits their therapeutic use. CONCLUSIONS: In order to achieve optimal glycemic control, by using the therapeutic effects of incretins, research has been directed to the development of synthetic analogues of GLP-1 resistant to DPP IV enzyme inactivation and DPP IV inhibitors.