The Structural, Crystallinity, and Thermal Properties of pH-responsive Interpenetrating Gelatin/Sodium Alginate-based Polymeric Composites for the Controlled Delivery of Cetirizine HCl.

OBJECTIVES: The present work aimed to design and synthesize pH-sensitive cross-linked Ge/SA hydrogels using different ratios of each polymer, and to investigate the effect of each polymer on dynamic, equilibrium swelling, and in vitro release pattern of cetirizine hydrochloride, which was selected as a model drug. MATERIALS AND METHODS: These gelatin and sodium alginate hydrogels were prepared at room temperature through free radical polymerization using glutaraldehyde as a crosslinker. These polymeric composites were used as model systems to envisage various important characterizations. The in vitro release pattern of drug was investigated in three different mediums (phosphate buffer solution of pH 1.2, 5.5, 7.5 whose ionic strength was kept constant). Various structure property relationships that affect its release behavior were determined such as swelling analysis, porosity, sol-gel analysis, average molecular weight between crosslinks (Mc), solvent interaction parameter (χ), volume fraction of polymer (V2,s) and diffusion coefficient. The structural, crystallinity, and thermal stability were confirmed using FTIR, XRD, and DSC analysis. RESULTS: These hydrogels showed maximum swelling at pH 1.2. Zero-order, first-order, Higuchi, and Peppas models were applied to demonstrate the release pattern of drug. The release of drug occurred through non-Fickian diffusion or anomalous mechanism. Porosity was found increased with an increase in concentration of both polymers, and porosity decreased when the concentration of the crosslinker was increased. Gel fraction increased with an increase in concentration of SA, Ge, and glutaraldehyde. CONCLUSION: The prepared pH sensitive hydrogels can be used as a potential carrier for the sustained delivery of cetirizine hydrochloride.

pH responsive cross-linked polymeric matrices based on natural polymers: effect of process variables on swelling characterization and drug delivery properties.

Introduction: The current work was aimed to design and synthesize novel crosslinked pH-sensitive gelatin/pectin (Ge/Pec) hydrogels using different polymeric ratios and to explore the effect of polymers and degree of crosslinking on dynamic, equilibrium swelling and in vitro release behavior of the model drug (Mannitol). Methods: The Ge/Pec based hydrogels were prepared using glutaraldehyde as the crosslinker. Various structural parameters that affect their release behavior were determined, including swelling study, porosity, sol-gel analysis, average molecular weight between crosslinks (Mc), volume fraction of polymer (V2,s), solvent interaction parameter (χ) and diffusion coefficient. The synthesized hydrogels were subjected to various characterization tools like Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and DSC differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Results: The hydrogels show highest water uptake and release at lower pH values. The FTIR spectra showed an interaction between Ge and Pec, and the drug-loaded samples also showed the drug-related peaks, indicating proper loading of the drug. DSC and TGA studies confirmed the thermal stability of hydrogel samples, while SEM showed the porous nature of hydrogels. The drug release followed non-Fickian diffusion or anomalous mechanism. Conclusion: Aforementioned characterizations reveal the successful formation of copolymer hydrogels. The pH-sensitive swelling ability and drug release behavior suggest that the rate of polymer chain relaxation and drug diffusion from these hydrogels are comparable which also predicts their possible use for site-specific drug delivery.

The structural, morphological and thermal properties of grafted pH-sensitive interpenetrating highly porous polymeric composites of sodium alginate/acrylic acid copolymers for controlled delivery of diclofenac potassium.

In present investigation new formulations of Sodium Alginate/Acrylic acid hydrogels with high porous structure were synthesized by free radical polymerization technique for the controlled drug delivery of analgesic agent to colon. Many structural parameters like molecular weight between crosslinks (Mc ), crosslink density (Mr ), volume interaction parameter (v2,s ), Flory Huggins water interaction parameter and diffusion coefficient (Q) were calculated. Water uptake studies was conducted in different USP phosphate buffer solutions. All samples showed higher swelling ratio with increasing pH values because of ionization of carboxylic groups at higher pH values. Porosity and gel fraction of all the samples were calculated. New selected samples were loaded with the model drug (diclofenac potassium).The amount of drug loaded and released was determined and it was found that all the samples showed higher release of drug at higher pH values. Release of diclofenac potassium was found to be dependent on the ratio of sodium alginate/acrylic acid, EGDMA and pH of the medium. Experimental data was fitted to various model equations and corresponding parameters were calculated to study the release mechanism. The Structural, Morphological and Thermal Properties of interpenetrating hydrogels were studied by FTIR, XRD, DSC, and SEM.

Neutrophil-to-lymphocyte ratio as a predictor of worsening renal function in diabetic patients (3-year follow-up study).

BACKGROUND: Previous studies have demonstrated the role of inflammation in diabetic nephropathy (DN). Neutrophil to lymphocyte ratio (NLR) rather than other white cell parameters was found to be a useful inflammatory marker to predict adverse outcomes in medical and surgical conditions. Nevertheless, the value of NLR in predicting DN has not been elucidated. METHOD: An observational study included 338 diabetic patients, who were followed at our clinic between 2007 and 2009. We arranged our patients into tertiles according to their 2007 NLR. The primary outcome was continuous decrease of GFR >12 mL/min between 2007 and 2009 with the last GFR <60 mL/min. RESULT: The lowest NLR tertile had fewer patients (2.7%) with primary outcome (i.e., worsening renal function) compared with middle and highest NLR tertiles, which had more patients with primary outcomes (8.7% and 11.5%, respectively) with a significant p-value 0.0164. When other potential confounders were individually analyzed with NLR tertile, the NLR tertiles remained a significant predictor of poor GFR outcome in the presence of other variables (hemoglobin A1C, systolic blood pressure, diastolic blood pressure, age, and congestive heart failure with p-values 0.018, 0.019, 0.017, 0.033, and 0.022, respectively). CONCLUSION: NLR predicted the worsening of the renal function in diabetic patients. Further studies are needed to confirm this result.