Hydroxyapatite - Carbon Nanotube Composites for Drug Delivery Applications

Abstract

The aim of this study was the synthesis of composites containing hydroxyapatite (Hap) or silicon substituted hydroxyapatite (HapSi), carboxyl functionalized carbon nanotubes (fMWCNT) and gelatin (G) in different ratios. Ibuprofen (IBU) was chosen as a model drug for the formulation of extended-release dosage forms. The obtained composites were characterized using X-ray diffraction, laser diffraction particle size analyzer, Brunauer-Emmett-Teller surface area measurements, transmission electron microscopy and Fourier transformed infrared spectroscopy. IBU adsorption and desorption was monitored by UV-VIS spectroscopy. The obtained results revealed that composites containing three components exhibit higher adsorption efficiency (Hap-fMWCNT-20G-82.7% and HapSi-fMWCNT-20G-84.6%) and extended-release of IBU, due to the chemical bonds between the carboxyl groups of IBU and the functional groups on the composite surface. The adsorption capacity of Hap composites is important for dental or orthopedic implants, the anti-inflammatory substances being adsorbed on their surface; but the adsorption capacity also enhances new bone formation (osteosynthesis) around the implants. These composites are thus attractive materials to be used in bone tissue engineering and drug delivery systems.

Hydroxyapatite and Silicon-Modified Hydroxyapatite as Drug Carriers for 4-Aminopyridine

“…It is worth mentioning that in the case of the HAP carrier, the released 4AP amount was of one order of magnitude greater than in the case of Si-containing carriers. On the one hand, this could be explained by the excellent retard property of the silica-containing samples [13], and on the other hand, by the fact that less 4AP was bound to the surface in the case of the Si-HAP sample than in the case of HAP (see Section 3.2). Probably due to the absence of agitation during the measurement in SBF (in order to eliminate degradation of the tablets to be analyzed), the amount of released drug was only the result of the dissolution of 4AP bound to the surface.…”

“…In our previous researches, we already investigated the sorption properties of HAP and various HAP-based composites with different adsorbates [9][10][11][12][13]. The additives, structural modifications and the adsorption efficiency were greatly influenced by the nature of the adsorbent.…”

Recent Trends in Hydroxyapatite Supplementation for Osteoregenerative Purposes

“…HAP with a Ca/P ratio bigger than 1.67 comprises more CaO than TCP and vice versa [ 6 , 7 ]. Structurally, HAP is similar to the bone mineral phase, presenting high biocompatibility and bioactive properties [ 8 , 9 ]. It has been proven that the biocompatibility and bioactivity of HAP, represented by osteoconductive and osteoinductive processes, support osseointegration.…”