Niladri Roy

Development and Characterization of Novel Medicated Hydrogels for Wound Dressing

The medicated hydrogels were prepared aseptically under moist heat treatment using polyvinylpyrrolidone (PVP), sodium-carboxymethylcellulose (CMC), polyethyleneglycol (PEG), agar, glycerin and/or boric acid (BA) and designated as PVP-CMC and PVP-CMC-BA. The aim of this study was to develop some medicinal values–based hydrogels. BA was used to build up the medicinal values (antiseptic and antimicrobial properties) within the hydrogels. Optical images, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy of the hydrogels indicated that boric acid is uniformly dispersed within the cross-linked hydrogel network that may heal and protect the wounds from infections/sepsis. Swelling study in presence of water and physiological saline solution confirmed its reasonable absorption capacity. The rheological properties and mechanical properties demonstrated that the boric acid incorporated hydrogels are quite flexible. Assessment of antimicrobial property study proves that PVP-CMC-BA (3% BA) has strong infection protection capacity.

Significant Characteristics of Medical-Grade Polymer Sheets and their Efficiency in Protecting Hydrogel Wound Dressings: A Soft Polymeric Biomaterial

Hydrogel dressings are soft biomaterials that need protection from external influences. Polymer sheets such as breathable film (BF) or breathable laminate (BL) were characterized in respect of water vapor transmission, water contact angle, microbial penetrability, and antimicrobial property to protect hydrogel dressings. The mechanical property and water retention ability of hydogels PVP-CMC and PVP-CMC-BA with and without BF and BL have been examined. Hydrogels covered with either BF or BL show better mechanical flexibility; however, their water retention capacity increases reasonably. The determined efficient properties of polymer sheets established that BF is better than BL as a protective sheet cover for hydrogel dressings.

Stability Study of Novel Medicated Hydrogel Wound Dressings

PVP-CMC and PVP-CMC-BA hydrogels were prepared for biomedical applications. These hydrogels were stored under 5°C ± 2°C, 22°C ± 3°C, and 40°C for 180 days to identify their suitable storage condition. At 5°C ± 2°C, hydrogels showed minimum alteration in physical properties. No microbial colonies appeared on PVP-CMC stored at 5°C ± 2°C, but they slowly appeared at 22°C ± 3°C and 40°C after 45 days. FTIR and antibacterial assay demonstrated that boric acid (BA) in hydrogel remained stable for 180 days. PVP-CMC-BA is more bio-stable than PVP-CMC because of BA, an antibacterial agent. Finally, 5°C ± 2°C was recommended as the best storage condition for both PVP-CMC and PVP-CMC-BA hydrogels.

Effectiveness of Polymer Sheet Layer to Protect Hydrogel Dressings

Two kinds of polymer sheet layers: breathable film (BF) and breathable laminate (BL) were chosen to cover hydrogel dressings (PVP-CMC and PVP-CMC-BA). The upper and lower surfaces of the polymer sheets were designated as BF (U) and BF (L) for BF and BL (U) and BL (L) for BL, respectively. Water vapor transmission (WVT) test reveals that both BL and BF have oxygen diffusion property, i.e. they are breathable. Microbial penetrability test shows that BF has more resistant property against microbial penetrability. Moisture retention capability proves that polymer sheets effectively reduce the tendency of rapid moisture loss from the hydrogels. According to all the results BF could be considered as more effective layer to protect the properties of hydrogel dressings.

Effect of Strain on Viscoelastic Behavior of PVP‐CMC Based Medicated Hydrogels

PVP‐CMC and PVP‐CMC‐BA are designated as medicated hydrogels which are elastic in nature like other gels and solids. This present work was focused on the effect of strain on viscoelastic behavior of these medicated hydrogels. Dynamic frequency sweep test at 10% strain and dynamic strain sweep tests at different angular frequencies were performed on these hydrogels. Freshly prepared hydrogels and hydrogels swelled for 60 min from dry state were chosen for the experiments. These two experiments reveal that both PVP‐CMC and PVP‐CMC‐BA hydrogels (fresh and swelled) maintain elastic behavior from very low to medium strain, but at high strain they become viscous in nature.

Importance of Viscoelastic Property Measurement of a New Hydrogel for Health Care

A simple technology based new hydrogel “PVP‐CMC‐BA” has been prepared by the scientists of Tomas Bata University in Zlin, Czech Republic. Its swelling property (in presence of water, human blood and different pH), antimicrobial property (in presence of skin infection causing agents like: Staphylococcus aureus; bacteria and Candida albicans; fungi) and viscoelastic properties such as storage modulus (G’), loss modulus (G”) and complex viscosity (η*) were investigated at room temperature (25–28° C) which demonstrate that PVP‐CMC‐BA hydrogel is maintaining requisite properties for health care application, specially as a wound dressing material. The elasticity and antimicrobial property of PVP‐CMC‐BA is directly correlated with percentage of boric acid, an antiseptic agent. The consequential values of viscoelastic properties of the hydrogel (before drying) enable us to understand its specific flexible condition to apply on the surface of human body.

Viscoelastic Properties and Morphology of Mumio-based Medicated Hydrogels

Novel medicated hydrogels were prepared (by moist heat treatment) with PVA, agar, mumio, mare’s milk (MM), seabuckthorn oil (SB oil) and salicylic acid (SA) for wound dressing/healing application. Scanning electron micrographs (SEM) show highly porous structure of these hydrogels. The swelling behaviour of the hydrogels in physiological solution displays remarkable liquid absorption property. The knowledge obtained from rheological investigations of these‐systems may be highly useful for the characterization of the newly developed topical formulations. In the present study, an oscillation frequency sweep test was used for the evaluation of storage modulus (G′), loss modulus (G″), and complex viscosity (η*) of five different formulations, over an angular frequency range from 0.1 to 100 rad.s−1. The influence of healing agents and swelling effect on the rheological properties of mumio‐based medicated hydrogels was investigated to judge its application on uneven surface of body.