Investigation of in vitro release model of injectable implants / 第二军医大学学报

ABSTRACT

Objective: To investigate the feasibility of in vitro release models of injectable implants. Methods: An RP-HPLC method was established for determination of norfloxacin (NF). The in vitro release profiles of injectable implants in four release models, including direct injection model, one-way cylinder, dialysis tube and home-made cylinder, were studied and compared with the in vivo release profiles. Results: The in vivo release of NF from injectable implants was much faster than the in vitro release of NF. The in vivo release was close to the zero-order release kinetics in the sustained release phase (1-20 d, r=0.993 5), while the in vitro release could be divided into slow phase and fast phase with 15 d as the turning point. Of the four in vitro release models, home-made cylinder showed the closest initial release to the initial release of NF in vivo. Conclusion: All the above four release models have limitations; they can not well reflect the in vivo release profiles of injectable implants; and further studies are needed for the in vitro release model of injectable implants.