Morphology effect of nano-hydroxyapatite as a drug carrier of methotrexate

Abstract

In this study, morphology effect of nano-hydroxyapatite as a drug carrier was investigated for the first time. Hydroxyapatite/methotrexate (HAp/MTX) hybrids with different morphologies were successfully prepared in situ using polyethylene glycol (PEG) as a template. SEM, TEM, XRD and FTIR results confirmed that the hybrids of different morphologies (laminated, rod-like and spherical) with similar phase composition and functional groups were obtained by changing the preparation parameters. UV-Vis spectroscopy was used to identify the drug loading capacity and drug release mechanism of the three hybrids with different morphologies. It is concluded that the laminated hybrid exhibits a higher drug loading capacity compared to the other two hybrids, and all the three hybrids showed a sustained slow release which were fitted well by Bhaskar equation. Additionally, the result of in vitro bioassay test confirms that the inhibition efficacy of the three hybrids showed a positive correlation to the drug loading capacity.

Preparation of fibrous hydroxyapatite particles by homogeneous precipitation and microwave-assisted hydrothermal heating

“…The results are shown in FIGURE 2, as a function of (NH 2 ) 2 CO concentration. When the (NH 2 ) 2 CO concentrations were 0.04 and 0.08 mol•dm 3 , CaHPO 4 and OCP Relating to the formations of CaHPO 4 and OCP, the former compound is stable for pH < 4 25 . On the other hand, the latter compound is favored as a metastable phase in the range of pH ≃ 4 to pH ≃ 6.5, although the non-stoichiometric HAp (i.e.,Ca 10x (HPO 4 ) x (PO 4 ) 6-x (OH) 2x ) is also thermosdynamically stable for pH > 4 25 .…”

“…(7). The noted reflections of 001, 002 and 003 in the CaHPO 4 indicate the anisotropic crystal growth normal to the c-axis direction 26 .…”

“…Also, the absorption peak at 964 cm 1 is assigned to the stretching vibration of the P-OH in the HPO 4 On the basis of the data regarding the phase identification of microwave-assisted hydrothermal heating, the resulting particle morphologies were studied by the FE-SEM and the long-axis length distributions were checked using the FE-SEM micrographs. The results are shown in FIGURE 6.…”

“…A hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 : HAp) possesses bone regenerative and biodegradable characteristics 1,2 , and it may be applied to the drug carriers 3,4 and scaffold 1,5 . Previously, HAp has been prepared by many chemical routes 6 .…”

“…Among these techniques, the homogeneous precipitation, using urea ((NH 2 ) 2 CO; precipitant), is attractive to prepare the anisotropically-grown HAp particles, via octacalcium phosphate (Ca 8 H 2 (PO 4 ) 6 • 5H 2 O; OCP）particles [8][9][10][11] and/or calcium hydrogen orthophosphate (CaHPO 4 or CaHPO 4 •2H 2 O) particles with the shapes of tubular, needle-like, lath-like, and rectangular prismatic crystals 14 . The hydrolysis of urea to dissociate the ammonia may be beneficial for such anisotropic particle growth of precursor of HAp, e.g., HAp particles with the long-axis lengths of approximately 100 m or shorter 15 and 50 ~ 150 m 16 , additionally using glutamic acid for the modulation of crystallization.…”