Abstract
In the present investigation, new formulations of CMCS/AA hydrogels with varying composition of Carboxymethyl chitosan, acrylic acid, and ethylene glycol dimethacrylate (EGDMA) were prepared by free radical polymerization technique using benzoyl peroxide as catalyst. The bioavailability of 5-FU through the oral route is very limited owing to its rapid metabolism and clearance from the general circulation. Current work was aimed at increasing the bioavailability of 5-FU via smart hydrogels and at investigating their potential in delivering 5-FU to target colon cancer. Swelling studies were carried out on dried hydrogel discs in different USP phosphate buffer solutions of various pH values. Porosity and gel fraction of all the samples were measured. 5-FU was used as a model drug and loaded in selected hydrogel samples. The amount of drug loaded and released was determined. Experimental data was fitted to various model equations, and corresponding parameters were calculated to study the release mechanism. Many structural parameters were calculated. The prepared hydrogels were also characterized by FTIR and SEM to study the structure, crystallinity, compatibility, and morphology of the smart hydrogels. The biocompatibility and cytotoxic potential blank and drug-loaded hydrogels were assessed through MTT assay. The prepared hydrogels were found to be an excellent carrier for 5-FU in targeting colon cancer.
Highlights
Colon cancer has been reported as a major cause of deaths worldwide [1, 2]
Since the pKa of acrylic acid lies between 4.5 and 5.0, the swelling capacity of polyacrylic acid (PAA) hydrogels is minimum at pH below 4 and higher at pH above 5, which is the desired property for oral controlled release drug delivery systems
The pH of the medium and pKa values of the acidic component of the polymer greatly affect the swelling behavior of the hydrogels. This is because the pH of the medium affects the ionization of carboxylic groups that results in huge variation in swelling kinetics of hydrogel. pH effect on swelling and drug release was measured in buffer solutions of pH (1.2, 5.5, 6.5, and 7.5), respectively
Summary
Colon cancer has been reported as a major cause of deaths worldwide [1, 2]. The primary treatment of choice is its surgical removal and early detection and resection be crucial for treating colorectal cancer [3, 4]. The extensive swelling of polyacrylic acid (PAA) hydrogels is based on the occurrence of carboxyl groups in the polymer network These groups are highly ionizable, strongly interact with water molecules, and sensitive to the changes in pH and ionic strength of the medium. Since the pKa of acrylic acid lies between 4.5 and 5.0, the swelling capacity of PAA hydrogels is minimum at pH below 4 and higher at pH above 5, which is the desired property for oral controlled release drug delivery systems. Due to the presence of amino groups in its side chain, CMCS shows a good ionic and pH sensitivity in aqueous solution [6] It has good physical, chemical, and biological characteristics such as high biocompatibility, bioadhesiveness, nontoxicity, and excellent gel-forming properties. The structure, crystallinity, and surface morphology of prepared hydrogels were analyzed by Fourier transformed infrared spectroscopy (FTIR) and scanning electron microscopy (SEM)
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