Role of the Pharmaceutical Excipients in the Tamoxifen Activity on MCF-7 and Vero Cell Cultures

Background: Microparticles are used for controlled drug delivery. With the aim of improving both bioavailability and tamoxifen selective toxicity, the activity of tamoxifen embedded in calcium alginate/chitosan microparticles was studied. Materials and Methods: Tamoxifen alone and embedded in microparticles prepared with sodium alginate from Kelco (62% mannuronic acid and 38% guluronic acid) and from Fluka (30% mannuronic acid and 70% guluronic acid) was added to MCF-7 and Vero cultures and evaluated for antiproliferative activity by the MTT test. Results: The use of Kelco or Fluka alginate resulted in different LD50 values on Vero and MCF-7 cultures, showing a higher cytotoxicity toward Vero cells treated with tamoxifen embedded in Kelco microparticles (25 mu M vs. 48 mu M on MCF-7 cells) but a selective toxicity with Fluka microparticles (25 mu M and 10 mu M on Vero and MCF-7 cells respectively). Conclusion: Microparticle formulation may improve selective toxicity according to the alginate employed: differences in the chemical alginate composition can dramatically change both drug activity and toxicity.