Using Carbomer-Based Hydrogels for Control the Release Rate of Diclofenac Sodium: Preparation and In Vitro Evaluation.

Muhammad Suhail,Muhammad Usman Minhas,Pao-Chu Wu

doi:10.3390/ph13110399

Abstract

The aim of the current research work was to prepare Car934-g-poly(acrylic acid) hydrogels by the free-radical polymerization technique. Various concentrations of carbopol, acrylic acid and ethylene glycol dimethacrylate were employed for the fabrication of Car934-g-poly(acrylic acid) hydrogels. Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Scanning electron microscope (SEM) and Powder X-ray diffractometry (PXRD) studies were performed to know the structural arrangement, thermal stability, physical appearance and amorphous network of developed hydrogels. FTIR analysis revealed that carbopol reacted with acrylic acid during the process of polymerization and confirmed the grafting of acrylic acid over the backbone of carbopol. TGA and DSC studies showed that developed hydrogels were thermally stable. Surface morphology was analyzed by SEM, which confirmed a porous network of hydrogels. PXRD analysis indicated that crystallinity of the drug was reduced by the amorphous network of hydrogels. Furthermore, swelling studies for all developed hydrogels were performed at both media, i.e., pH 1.2 and 7.4, and higher swelling was exhibited at pH 7.4. Sol–gel analysis was performed to evaluate the soluble unreacted part of the fabricated hydrogels. Similarly, an in-vitro study was conducted for all hydrogel formulations at both acidic (pH 1.2) and basic (pH 7.4) mediums, and a greater drug release was observed at pH 7.4. Different kinetics such as zero-order, first-order, the Higuchi model and the Korsmeyer–Peppas model were applied to know the mechanism of release order of drugs from the hydrogels.

Highlights

Hydrogels are three-dimensional structures with the capability to absorb and hold a high quantity of water without losing structural consistency [1]
Hydrogels are very stable by nature; due to which, the solutions absorbed by hydrogels remain inside its network, even in the presence of any external force [2]
Hydrogels are considered as a potential candidate for various biomedical applications, including drug delivery and tissue engineering, due to their super-absorbency, softness, viscoelasticity, hydrophilicity, biocompatibility and biodegradability

Summary

Introduction

Hydrogels are three-dimensional structures with the capability to absorb and hold a high quantity of water without losing structural consistency [1]. A significant role is played by these different hydrophilic groups of polymers in the formation of noncovalent bonds of hydrogels with other numerous biological tissues like epithelial tissues and mucous membranes [5]. Two types of crosslinking occur in hydrogels, i.e., (a) physical or (b) chemical, which restricts the hydrogels from being dissolved even when holding a high concentration of water or other fluids [6]. Hydrogels are considered as a potential candidate for various biomedical applications, including drug delivery and tissue engineering, due to their super-absorbency, softness, viscoelasticity, hydrophilicity, biocompatibility and biodegradability. The reversible responses to various stimuli such as pH, temperature, electric field, magnetic field, biological molecules and ionic strength of a solution is another astonishing property of hydrogels [8,9] that enhances their importance further, for widespread biomedical applications [10]

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Conclusion