[Preparation and characterization of ampicillin loaded ethylcellulose nanospheres]

Ampicillin sodium was embeded in ethylcellulose (EC) nanospheres made of low-molecular-weight EC. Low-molecular-weight EC was attained with ethylcellulose being degraded by 34% (w/w) nitric acid; Fourier transform infrared (FTIR) spectroscopy, 13C-NMR, element analysis confirmed that the basic structure and major properties of low-molecular-weight EC maintained agreement with those of undegraded EC except that the polymerization degree of EC decreased. Wide-angle X-ray diffraction demonstrated that the crystallinity of degraded EC decreased. Ampicillin sodium loaded EC nanospheres were characterized by transmission electron microscopy, FTIR and in vitro drug release. Molecular weight of EC would affect the size of nanospheres, distribution and drug encapsulation efficiency. Drug loaded nanospheres resulted in the drug control release in 3-10 hours.