Study On The Sterilization Methods Of Dextran Composite Magnetic Nanoparticles

Magnetic nanoparticles present a promising application prospect in biomedical field due to its unique physical and chemical properties. The dextran composite magnetic nanoparticles (DCMN) developed in our lab were expected to be an ideal magnetically targeted carrier, because of their good superparamagnetism, biocompatibility and biodegradability properties. As a pharmaceutical preparation for injection, the sterility is a very important factor. It is necessary to establish the appropriate method of sterilization. Herein the sterilization of magnetic nanoparticles by using autoclaving, dry heat and60Co-γ irradiation was investigated, giving the following results:1. The sterilization of DCMN using autoclaving and dry heat was investigated. The experimental results showed that the autoclaving methods destroyed the dispersion of DCMN, so the autoclaving methods are not suitable for these particles. The dry heat methods had no influence on the physicochemical properties such as zeta potential, magnetic responsiveness, major functional groups but effect the particle size and drug load efficiency of doxorubicin.2. The60Co-γ irradiation was used as sterilization method for DCMN with different irradiation doses of9kGy,15kGy and25kGy. The formulation showed excellent stability. The irradiation did not influence the physicochemical parameters of the nanoparticles, such as the morphology, particle size, zeta potential, magnetic responsiveness, major functional groups, even the drug load efficiency and release rate of doxorubicin.3. According to the Chinese Pharmacopoeia, the sterility test for the irradiated DCMN was established. The validation for the method of sterility test was also studied, and the validation test proved that this method of sterility test was effective and reproducable. The average bioburden of the untreated lyophilized formulation was found to be66.7CFU/g. The sterility testing and microbiological evaluation revealed that the irradiation dose of15 kGy was sufficient for the sterilization of the nanoparticles.