Synthesis, Characterization, and Investigation of Doxorubicin Drug Release Properties of Poly(acrylamide-co-acrylic Acid/Maleic Acid)-Hydroxyapatite Composite Hydrogel

Abstract

Background: Hydroxyapatite and its derivatives have been used for a lot of applications. One of them is drug release studies. Due to its low adhesion strength and lack of the strength and durability required for load-carrying applications, there is a need to improve the properties of hydroxyapatite. For this aim, the most important factors are increasing pH sensitivity and preventing coagulation. Mixing it with multifunctional polymers is the best solution. Objectives: The main objectives are: 1- preparing poly(acrylamide-co-acrylic acid/maleic acid)- hydroxyapatite (PAm-co-PAA/PMA–HApt), 2- assessment of (PAm-co-PAA/PMA–HApt) and dox-loaded poly(acrylamide-co-acrylic acid/maleic acid) (Dox-(PAm-co-PAA/PMA–HApt)) composite hydrogels, and 3- elucidating the difference in behavior of drug release studies between hydroxyapatite (HApt) and poly(acrylamide-co-acrylic acid/maleic acid) composite hydrogels. Methods: A composite of PAm-co-PAA/PMA–HApt was prepared by direct polymerization of acrylamide-co-acrylic acid/maleic acid in a suspension of HApt. The drug loading and release features of PAm-co-PAA/PMA–HApt and HApt were then investigated for doxorubicin (dox) release. Using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric analysis (TG/DTA), this unique composite hydrogel has been physicochemically investigated. Also, a colorimetric assay was used to assess the in vitro biocompatible support and anticancer activity of HApt and the newly developed composite hydrogel XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay. Results: According to the results of drug release studies of this new material, it is pH sensitive, and PAm-co-PAA/PMA–HApt demonstrated a faster release than HApt at 37°C in the acidic solution of pH 4.5 than in the neutral solution of pH 7.4. The XTT assay outcomes also demonstrated the biocompatibility of PAm-co-PAA/PMA–HApt and HApt and the cytotoxic effect of dox-loaded PAm-co-PAA/PMA–HApt. Conclusion: It should be inferred that the drug release profile was improved at pH 4.5 by the newly produced pH-sensitive composite hydrogel.