We present a novel and robust delivery platform for camptothecin (CPT) based in silica nanoparticles (SNP) of 5-15 nm diameter that transport the drug attached by ester bond in 20-OH position. The surface of these SNP is functionalized with carboxylic groups. These are ionized at physiological pH, thus, provoking electrostatic repulsion and avoiding particle aggregation, which allows the preparation of stable colloids in aqueous medium. Camptothecin-loaded silica nanoparticles (SNP-CPT, 5 wt% CPT) show high stability in human plasma, with less than 8% hydrolysis in 24 h. In general, the ester bond in 20-OH position looks pretty stable at pH below 8. In vitro activity of CPT (DMSO solution), SNP and SNP-CPT was tested by MTT assay during 72 h over four cell lines: HeLa, U87MG, HCT-116 and MDA-MB-231, with final doses ranging from 0.025 ng mL-1 to 2500 ng mL-1 (in CPT equivalents). SNP-CPT induces cell death at slightly higher concentration than the free drug in the four lines tested, HeLa being the most sensitive, whereas CPT-free SNP do not alter cell proliferation or morphology.
Journal: TechConnect Briefs
Volume: 3, Nanotechnology 2010: Bio Sensors, Instruments, Medical, Environment and Energy
Published: June 21, 2010
Pages: 320 - 323
Industry sector: Medical & Biotech
Topics: Biomaterials, Materials for Drug & Gene Delivery