Controlled release of acetylsalicylic acid via hydroxyapatite prepared with different templates

Abstract

Drug delivery systems are systems that reduce the dose of a drug, extend the dosing interval, eliminate side effects, and ensure that the drug reaches the target tissue in a safe, controlled, and effective manner. Hydroxyapatite (HAP) is an inorganic material based on calcium phosphate and is an effective adsorbent with excellent biocompatibility and bioactivity due to its similarity to the mineral components of human bone. In this study, the adsorption and desorption behaviors of acetylsalicylic acid (ASA) from aqueous solutions were investigated on template-modified hydroxyapatite. Hydroxyapatite (HAP) was synthesized by the chemical precipitation method and modified with various templates such as cetyltrimethylammonium bromide (CTAB), Pluronic® P-123 (P123), and Pluronic® F-127 (F127). X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to characterize the synthesized HAP samples. Equilibrium adsorption isotherms and kinetics for ASA-HAP adsorption were studied and best represented by the Langmuir isotherm. The results suggest that HAP is suitable as an alternative carrier for the adsorption and controlled release of ASA. Maximum ASA loading conditions were selected as 35 °C, 60 min. 0.5 mg/mL ASA solution, and 3 mg adsorbent. The adsorption capacity of HAP was improved from 237.02 mg g⁻¹ to 280.27 mg g⁻¹ using CTAB as a template. The release amount was decreased from 82.99 to 68.03% in the modified samples of HAP and exhibits a more controlled release profile than the untreated samples of HAP.