Kunal Pal

Preparation and characterization of polyvinyl alcohol-gelatin hydrogel membranes for biomedical applications.

The purpose of this research was to design and develop hydrogels by esterification of polyvinyl alcohol (PVA) with gelatin. The membranes were characterized by Fourier Transform Infrared (FTIR) spectroscopy, x-ray diffraction (XRD), and differential scanning calorimetry. The viscosity of the esterified product (as solution) was compared with the mixture of PVA and gelatin of the same composition. The mechanical properties of the hydrogels were characterized by tensile tests. Swelling behavior and hemocompatibility of the membrane were also evaluated. The diffusion coefficient of salicylic acid (SA), when the receptor compartment contained Ringers solution, through the membrane was determined. SA was used as a model drug. FTIR spectra of the membranes indicated complete esterification of the free carboxylic groups of gelatin. XRD studies indicated that the crystallinity of the membranes was mainly due to gelatin. The comparison of viscosity indicated an increase in segment density within the molecular coil. The membrane had sufficient strength and water-holding capacity. Hemocompatibility suggested that the hydrogel could be tried as wound dressing and as an implantable drug delivery system. The diffusion coefficient of SA through the membrane was found to be 1.32×10−5 cm2/s. The experimental results indicated that the hydrogel could be tried for various biomedical applications.

Polymeric Hydrogels: Characterization and Biomedical Applications

Hydrogels are cross-linked polymeric networks, which have the ability to hold water within the spaces available among the polymeric chains. The hydrogels have been used extensively in various biomedical applications, e.g., drug delivery, cell carriers and/or entrapment, wound management and tissue engineering. Though far from extensive, this article has been devoted to study the common methods used for the characterization of the hydrogels and to review the range of applications of the same in health care.

Polymers in Mucoadhesive Drug-Delivery Systems: A Brief Note

Bioadhesion can be defined as the process by which a natural or a synthetic polymer can adhere to a biological substrate. When the biological substrate is a mucosal layer then the phenomena is known as mucoadhesion. The substrate possessing bioadhesive property can help in devising a delivery system capable of delivering a bioactive agent for a prolonged period of time at a specific delivery site. The current review provides a good insight on mucoadhesive polymers, the phenomenon of mucoadhesion and the factors which have the ability to affect the mucoadhesive properties of a polymer.

Organogels: Properties and Applications in Drug Delivery

An organogel, a viscoelastic system, can be regarded as a semi-solid preparation which has an immobilized external apolar phase. The apolar phase is immobilized within spaces of the three-dimensional network structure formed due to the physical interactions amongst the self-assembling structures of compounds regarded as gelators. In general, organogels are thermodynamically stable in nature and have been explored as matrices for the delivery of bioactive agents. In the current paper, attempts have been made to understand the properties of organogels, various types of organogelators and some applications of the organogels in controlled delivery.

Effect of flaxseed gum on reduction of blood glucose and cholesterol in type 2 diabetic patients

The effects of ingestion of flaxseed gum on blood glucose and cholesterol, particularly low-density lipoprotein cholesterol, in type 2 diabetes were evaluated. Flaxseed gum was incorporated in wheat flour chapattis. Sixty patients of type 2 diabetes were fed a daily diet for 3 months, along with six wheat flour chapattis containing flaxseed gum (5 g), as per the recommendations of the American Diabetic Association. The control group (60 individuals) consumed an identical diet but the chapattis were without gum. The blood biochemistry profiles monitored before starting the study and at monthly intervals showed fasting blood sugar in the experimental group decreased from 154±8 mg/dl to 136±7 mg/dl (P=0.03) while the total cholesterol reduced from 182±11 mg/dl to 163±9 mg/dl (P=0.03). Results showed a decrease in low-density lipoprotein cholesterol from 110±8 mg/dl to 92±9 mg/dl (P=0.02). The study demonstrated the efficacy of flax gum in the blood biochemistry profiles of type 2 diabetes.

Polyvinyl alcohol--gelatin patches of salicylic acid: preparation, characterization and drug release studies.

Polyvinyl alcohol—gelatin patches were developed and salicylic acid was incorporated at different stages of preparation of the patches. The patches were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry, tensile strength test, and scanning electron microscopy. The release patterns of the drug from the patches were also studied. The FTIR spectra of the blank patch indicated complete esterification of the free carboxylic groups of gelatin. The XRD studies indicated a crystalline form of the drug entrapped in the patches. Release of the drug from the patches followed Higuchian/Fickian kinetics indicating a diffusion-controlled release process.

Development of porous hydroxyapatite scaffolds

ABSTRACT Porous objects of hydroxyapatite (HA) were prepared by mixing sodium chloride as channeling agent with ultra high molecular weight polyethylene (UHMWPE) as a binder and hydroxyapatite powder. After hot isostatic pressing (HIP) and dissolving the channeling agent, the bioceramic showed an interconnecting porosity with pore diameters in the range of 160–220 µm. The method can be used for any material that is insoluble in water. Such objects are promising for bone regeneration because the interconnecting porosity in implants provides a good environment for bone attachment and in-growth.

Development of carboxymethyl cellulose acrylate for various biomedical applications.

The purpose of this work is to prepare a pH-sensitive hydrogel membrane of sodium carboxymethyl cellulose acrylate for drug delivery and other biomedical applications. The hydrogel was made by esterification of sodium carboxymethyl cellulose (SCMC) and acryloyl chloride (ACl). The esterified product was characterized by FTIR spectroscopy and XRD. Swelling, hemocompatibility, water vapor transmission rate, contact angle and diffusional studies were also done. Biocompatibility of the membrane was established by quantification of cell growth of L929 cells and mice splenocytes. The FTIR spectrum of the hydrogel suggested the formation of ester bonds between the hydroxyl groups of sodium carboxymethyl cellulose and the carbonyl group of acryloyl chloride. Water vapor transmission rate, hemocompatibility, contact angle and swelling studies indicated that the hydrogel can be tried as a wound dressing material. The hydrogel showed pH-dependent swelling behavior arising from the acidic pendant group in the polymer network. The permeability of the hydrogel membrane produced, as shown by salicylic acid diffusion, increased in response to an increase in pH of the external medium. The hydrogel membrane was permeable to salicylic acid at pH 7.2 but not at pH 2.0 (0.01N HCl). The effect of changes of pH on the hydrogels permeability was found to be reversible. The hydrogel membrane was found to be compatible with the L929 mice fibroblast cell line and mice splenocytes. The esterified product of SCMC and ACl swells on increase of pH indicating its possible use in a pH-sensitive drug delivery system and as a wound dressing material.

Calcium alginate-carboxymethyl cellulose beads for colon-targeted drug delivery

The present study delineates preparation, characterization and application of calcium alginate (CA)-carboxymethyl cellulose (CMC) beads for colon-specific oral drug delivery. Here, we exploited pH responsive swelling, mucoadhesivity and colonic microflora-catered biodegradability of the formulations for colon-specific drug delivery. The CA-CMC beads were prepared by ionic gelation method and its physicochemical characterization was done by SEM, XRD, EDAX, DSC and texture analyzer. The swelling and mucoadhesivity of the beads was found higher at the simulated colonic environment. Variation was more prominent in compositions with lower CMC concentrations. CA-CMC formulations degraded slowly in simulated colonic fluid, however the degradation rate increased drastically in the presence of colonic microflora. In vitro release study of anticancer drug 5-fluorouracil (5-FU) showed a release (>90%) in the presence of colonic enzymes. A critical analysis of drug release profile along with FRAP (fluorescence recovery after photobleaching) study revealed that the presence of CMC in the formulation retarded the release rate of 5-FU. 5-FU-loaded formulations were tested against colon adenocarcinoma cells (HT-29). Cytotoxicity data, nuclear condensation-fragmentation and apoptosis analysis (by flow cytometry) together confirmed the therapeutic potential of the CA-CMC formulations. In conclusion, CA-CMC beads can be used for colon-specific drug delivery.

Organogels as Matrices for Controlled Drug Delivery: A Review on the Current State

Over the last two decades, organogels have found tremendous use in the pharmaceutical, food, and cosmetics industries with notable developments as drug delivery matrices and trans and saturated fat replacers in processed foods. The functionality of organogels benefits from their ease of preparation, cost effectiveness, and ability to contain both hydrophilic and lipophilic constituents. This review provides thorough insight into different organogelators, their mechanisms of organogel formation, various characterization techniques and their biocompatibility when administered in vivo. Finally, a special treatise is given on the applications of organogels as controlled drug delivery vehicles for topical, dermal/transdermal, parenteral, oral, and nasal routes. In situ forming organogels and their potential for tailored release of incorporated active ingredients are also discussed.