Protein Drug Delivery using Swellable Organically Modified Silica

Stephen Wanner, The College of Wooster


Despite an increase in spending by pharmaceutical companies, development and approval of new drug agents has been on the decline in the past ten years. Even with an estimated record high 132 billion dollars spent in 2011 on design and development, only 28 new drugs were approved for use by the FDA. Although drugs fail to reach FDA approval for numerous reasons, lack of efficient drug delivery has been a major cause. Recent investigations of swellable organically modified silica (SOMS) demonstrate the material's potential use as a drug delivery system. The aim of this study was to evaluate SOMS as a possible drug delivery system, specifically in regards to protein drug delivery. Three separate evaluations were made as part of this study. First, biocompatibility was evaluated by growing E. coli in liquid media with SOMS and monitoring growth rate. No inhibition of E. coli growth was noted with SOMS. Instead, growth was slightly enhanced as the SOMS material absorbed waste products from the media. Second, the ability of SOMS to be loaded with proteins and later released in a stimulated manner was investigated. The capacity of SOMS for sustained protein release was determined by measuring the elution of lipase, bovine serum albumin (BSA), hemoglobin, and myoglobin from SOMS upon alternation of the aqueous environment with a co-solvent, ethanol. The results showed that SOMS is able to entrap and allow for release of proteins in the presence of a stimulus. Third, the stability and folded state of lipase, BSA, hemoglobin, and myoglobin entrapped in SOMS was analyzed through fourier transform infrared spectroscopy (FT-IR). The position of the amide I bond (~1600cm-1) was monitored and indicated that entrapped protein was not denatured, but may be in a uniquely folded conformation due to being constrained in a hydrophobic nanoporous matrix.


© Copyright 2013 Stephen Wanner