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1 An investigation of micro-hydroxyapatite spheres loaded with indomethacin for targeted drug delivery
  1. Xiue Ren,
  2. Hongjuan Weng,
  3. Xianhe Wang,
  4. Liying Wang
  1. Department of Chemistry and Pharmacy, Zhuhai College of Jilin University, Zhuhai, China


Objectives A major obstacle to be overcome for oral drug delivery is that drug absorption/release must be avoided before the drug reaches the target site. In an attempt to overcome this challenge, we selected synthetic hydroxyapatite (HA) as a drug carrier for the hydrophobic drug indomethacin (IDM) used in local treatment of the colon, exploring the loaded drug and in vitro release characteristics of IDM/HA.

Methods An easy one-step hydrothermal method was employed to prepare micro-hydroxyapatite (HA) spheres. Infrared spectroscopy, X-ray diffraction and scanning electron microscopy further confirmed the composition, structure and morphology of the obtained sample. In vitro release of the anti-inflammatory drug (IDM) was performed successively under simulated conditions. The loading and release profiles of the drug were analysed by UV-spectrophotometry.

Results The use of ethanol enhances solubilization, and the drug loading rate is about 62.21% at 37° C for 12 hours when the mass ratio of IDM/HA is 2:1. The in vitro release of IDM/HA is dependent on solution pH. There is almost no release of IDM (only 0.159%) at pH 1.0, poor release (about 10.55%) at pH 6.8, and a cumulative release rate of up to 84.95% at pH 7.8. These results suggest that HA particles can be used as a pH responsive vehicle for delivering drugs.

Conclusions The as-synthesized micro-hydroxyapatite spheres may act as a promising drug delivery system due to their good biocompatibility, pH sensitivity and high drug loading/release efficiency. The IDM/HA drug delivery system satisfies the basic demand of oral site-specific delivery.

Acknowledgments This work was financially supported by a college students’ innovative training project (Grant No. 4041906168).

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