Improvement of Drug-Loading Properties of Hydroxyapatite Particles Using Triethylamine as a Capping Agent: A Novel Approach

Abstract

Particles that modify delivery characteristics are a focus of drug-loading research. Hydroxyapatite particles (HAPs) have excellent biocompatibility, shape controllability, and high adsorption, making them a potential candidate for drug-delivery carriers. However, there are still some defects in the current methods used to prepare HAPs. In order to avoid agglomeration and improve the drug-loading properties of HAPs, the present study provides a novel triethylamine (TEA)-capped coprecipitation template method to prepare HAPs at room temperature. In addition, pure water and anhydrous ethanol were used as solvents to investigate the capping effect of the small-molecule capping agent TEA during the synthesis of HAPs. The results showed that the HAPs prepared in the TEA ethanol system had a smaller particle size (150–250 nm), better dispersion and higher crystallinity. The results were significantly different from those of the conventional preparation methods without TEA. However, the hydroxyapatite crystal would agglomerate to a certain extent after being stored for a period of time, forming micro/nano-sized agglomerates of nanocrystals. FITR analysis and SEM observation showed that the capping effect of TEA promoted the formation of a smaller template and dispersed HAPs were quickly formed by dissolution and reprecipitation processes. The drug-loading experiments showed that the HAPs prepared in the TEA ethanol system had high drug-loading capacity (239.8 ± 13.4 mg·g−1) as well as an improved drug-release profile demonstrated in the drug-release experiment. The larger specific surface area associated with the smaller particle size was beneficial to the adsorption of drugs. After drying at 60 °C, TEA was evaporated from the HAPs which agglomerated into larger micron particles with more drug encapsulated. Thus, the effect of a sustained release was achieved. In the present research, a novel approach was developed by using triethylamine as the capping agent to prepare micro/nano-sized agglomerates of HAP nanocrystals with improved drug loading, which is predicted to have potential application in drug delivery.

Glucose-Targeted Hydroxyapatite/Indocyanine Green Hybrid Nanoparticles for Collaborative Tumor Therapy

“…Previous research has shown that highly crystallized nHAs can absorb or load more drug molecules owing to their high pore volume and sufficient pore size. 4,32 ICG molecules were clearly observed in HRTEM images (Figure S3b), which strongly supported the above loading mechanism of nHA. Besides, all particles displayed a similar crystal lattice fringes, indicating that glucose modification or ICG loading after the formation of particles has no significant effect on the crystalline phases of nHA.…”

Photoluminescent Properties of Hydroxyapatite and Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

“…Furthermore, hydroxyapatite is naturally found in vertebrate hard tissues [3] and invertebrate shells [4]. Currently, hydroxyapatite is used for other purposes, e.g., as a heterogeneous catalyst [5], an adsorbent [6], a source of biofuel cells [7], a bioimaging agent [8], in glassy carbon electrodes [9], and in drug-delivery carriers [10].…”

Synthesis and evaluation of nanosystem containing chondroitinase ABCI based on hydroxyapatite

“…Drug-loading research has concentrated on the creation of particle medication delivery methods over the last 10 years. Due to their biocompatibility and bioaffinity, as well as their good biological activity and great stability, bioceramic particles have garnered increased attention among these systems (Wen et al 2021 ). The majority of human bones and teeth are made of hydroxyapatite, which has the chemical formula (Ca 10 )(PO 4 ) 6 (OH) 2 .…”