Sucrose esters (SE) are surfactants with potential pharmaceutical applications because of their low toxicity, biocompatibility, and excellent biodegradability. Biodegradable and biocompatible copolymeric hydrogels based on glucose-6-acrylate-1, 2, 3, 4-tetraacetate (GATA) and methacrylic acid (MAA) were designed and synthesized. Because of the growing importance of sugar-based hydrogels as drug delivery systems, these new pH-responsive glucose-containing copolymeric hydrogels were investigated for oral drug delivery. The GATA monomer was synthesized and characterized. The copolymeric hydrogel was synthesized by free-radical polymerization. Azobisisobutyronitrile (AIBN) was the free-radical initiator employed and Cubane-1, 4-dicarboxylic acid (CDA) linked to two 2-hydroxyethyl methacrylate (HEMA) group was the crosslinking agent (CA) used for hydrogel preparations. The hydrogels were characterized by differential scanning calorimetry and FT-IR. Equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids (SGF and SIF, respectively). A model drug, olsalazine [3, 3َ -azobis (6-hydroxy benzoic acid)] (OSZ) an azo derivative of 5-aminosalicylic acid (5-ASA), was entrapped in these gels and the in vitro release profiles were established separately in both enzyme-free SGF and SIF. The drug release was found to be faster in SIF. The drug-release profiles indicated that amount of drug release depends on their degree of swelling and crosslinking.

A series of acrylic terpolymers containing silyl pendant groups was prepared by free radical cross-linking copolymerization. Me 3 Si, Et 3 Si and t-BuMe 2 Si together with cubane-1, 4-dicarboxylic acid (CDA) were covalently linked with 2-hydroxyethyl methacrylate (HEMA). The silyl-linked HEMA are abbreviated as TMSiEMA, TESiEMA and TBSiEMA respectively. Cubane-1, 4-dicarboxylic acid (CDA) linked to two HEMA group is the cross-linking agent (CA). Free radical cross-linking terpolymerization of the methyl methacrylate (MMA) and methacrylic acid (MAA) with two different molar ratios of organosilyl monomers and CA was carried out at 60-70 • C. The compositions of the cross-linked three-dimensional polymers were determined by FT-IR spectroscopy. The glass transition temperature (Tg) of the network polymers was determined calorimetrically. The Tg of network terpolymers increases with increasing of cross-linking degree. Equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids (SGF and SIF, respectively). The gels swelled more in SIF than in SGF. The swelling behaviour of the copolymers was dependent on the content of MAA groups and caused a decrease in gel swelling in pH 1 or an increase in gel swelling in pH 7.4. Based on the great difference in swelling ratio at pH 1 and 7.4 for P-1, P-6 and P-10 appear to be good candidates for colon-specific drug delivery.

Because of the growing importance of pH-sensitive hydrogels as drug delivery systems, biocompatible copolymeric hydrogels based N-vinyl-2-pyrrolidinone (NVP) and methacrylic acid (MAA) were designed and synthesized. These hydrogels were investigated for oral drug delivery. Radical copolymerizations of N-vinyl-2-pyrrolidinone (NVP) and methacrylic acid (MAA) with the various ratios of crosslinking agent were carried out at 70°C. Azabisisobutyronitrile (AIBN) was the free-radical initiator employed and Cubane-1,4-dicarboxylic acid (CDA) linked to two 2-hydroxyethyl methacrylate (HEMA) group was the crosslinking agent (CA) used for hydrogel preparations. The hydrogels were characterized by differential scanning calorimetry and FT-IR. Equilibrium swelling studies were carried out in enzymefree simulated gastric and intestinal fluids (SGF and SIF, respectively). A model drug, olsalazine [3,3¢-azobis (6-hydroxy benzoic acid)] (OSZ) as an azo derivative of 5-aminosalicylic acid (5-ASA), was entrapped in these gels and the in-vitro release profiles were established separately in both enzyme-free SGF and SIF. The drug-release profiles indicated that the amount of drug released depended on the degree of swelling. The swelling was modulated by the amount of crosslinking of the polymer bonded drug (PBDs) prepared. Based on the great difference in hydrolysis rates at pH 1 and 7.4, these pH-sensitive hydrogels appear to be good candidates for colon-specific drug delivery.

Crosslinked 2-hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAA) copolymer hydrogels were studied as drug delivery systems. Terephthalic acid was covalently linked with 2-hydroxyethyl methacrylate (HEMA), abbreviated as cross-linking agent (CA). Free radical copolymerization of HEMA and MAA with terephthetalic acid (CA) (2, 4, and 6%) as crosslinking agent were carried out at 70°C. The structure of the CA was confirmed by FT-IR, 1H-NMR and 13C-NMR spectroscopy. The composition of the crosslinked three-dimensional polymers were determined by FTIR spectroscopy. Glass transition temperature (Tg) of the network polymers was determined calorimetrically. The effect of copolymer composition on the swelling behavior and hydrolytic degradation was studied in simulated gastric fluid (SGF, pH 1) and simulated intestinal fluid (SIF, pH 7.4). The swelling and hydrolytic behavior of the copolymers depended on the content of MAA which caused a decrease in gel swelling in SGF or an increase in gel swelling in SIF. It was observed that in acidic media hydrogen bonds formed due to the protonation of the carboxylic acid groups of the MAA while in more basic or neutral conditions electrostatic repulsion occurred between the ionized carboxylic acid groups. This complex behavior affected the macroscopic swelling properties of the resultant hydrogels. The amount of drug release depended on the degree of hydrogel swelling and crosslinking.

Background Dietary modification is considered as one of the main strategies in the management of nonalcoholic fatty liver disease (NAFLD). The objective of this study was to systematically investigate the effect of dietary interventions on the cardio-metabolic risk factors, including lipid profile and insulin resistance in this population. Methods We searched electronic databases of PubMed and Scopus until January 2020 and included randomized controlled trials that compared the effect of dietary modifications vs. control on lipid profile and insulin resistance in patients with NAFLD. The random-effect analysis was performed to calculate pooled weighted mean differences (WMD). Results Our finding showed that serum triglycerides (TG) (n=5, WMD -38.50 mg/dL, 95% confidence interval [CI] -61.68 to -15.31; P=0.001) and total cholesterol (TC) (n=4, WMD -18.70 mg/dL, 95%CI -34.85 to -2.53; P=0.023) decrease following diet intervention along with marginally significant weight reduction (n=5, WMD -3.61 mg/dL, 95%CI -7.25 to 0.04; P=0.053). There was no change in the homeostatic model assessment for insulin resistance, high- and low-density lipoprotein (LDL) levels (P>0.05). Subgroup analysis revealed that Mediterranean diet reduced TG (n=2, WMD -57.52 mg/dL, 95%CI -75.73 to -39.31; P<0.001) and weight (n=2, WMD -7.59 Kg, 95%CI -13.53 to -1.66; P=0.012), and also increased LDL level (n=2, WMD 29.73 mg/dL, 95%CI 13.82-45.65; P<0.001). However, standard hypocaloric diet improved TC (n=2, WMD -23.20 mg/dL, 95%CI -36.96 to -9.44; P=0.001) and LDL (n=2, WMD -16.82 mg/dL, 95%CI -29.44 to -4.19; P=0.009). Conclusion Dietary modifications may improve serum TG, TC, and obesity in NAFLD.