The invention provide a silica nanoparticle comprising a non-porous matrix of silicon-oxygen bonds, wherein the matrix comprises organic agents conjugated to silicon or oxygen atoms in the matrix, the organic agents are conjugated to the matrix through linker L groups, wherein the linker L comprises, for example, an ester, urea, thiourea, or thio ether group, and wherein the diameter of the nanoparticle is about 15 nm to about 200 nm. The invention also provides novel methods of making and using the silica nanoparticles described herein.
Camptothecin-20-PEG ester transport forms: the effect of spacer groups on antitumor activity
作者:R Greenwald
DOI:10.1016/s0968-0896(98)00005-4
日期:1998.5
An improved synthesis of the hindered PEG-camptothecin diester transport form has been achieved using the Mukaiyama reagent. We have also assessed the effect of changing the electronic configuration of the (d-position of PEG-camptothecin transport forms on the rates of hydrolysis of the pro-moiety, and attempted to correlate these differences to efficacy in two animal models. In addition to the simple substitution of N for O, other synthetic modifications of these atoms were accomplished by employing heterobifunctional linker groups. The half lives by disappearance (rates of hydrolysis) of the transport forms in buffer and rat plasma were determined. It was established that anchimeric assistance to hydrolytic breakdown of the pro-moiety occurs in a predictable manner for some of these compounds. Results for the new derivatives in a P388 murine leukemic model and HT-29 human colorectal xenograft study are also presented. The use of a glycine linker group was found to provide similar efficacy in rodent models to that of simple camptothecin 20-PEG ester, and displayed enhanced pharmacokinetics. (C) 1998 Elsevier Science Ltd. All rights reserved.