Stimulus responsive hydrogels for oral drug delivery of colonoscopy preparations

Phuong Anh Nguyen1, Sarah Mounho2, Darnell Cuylear1, Heather Canavan1

  1. University of New Mexico
  2. University of Texas at Austin

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States. The most reliable screening method of CRC is a colonoscopy which requires a 4-Liter poly(ethylene glycol) electrolyte lavage solution (PEG-ELS) for preparation. Many patients who abstain reporting refusal due to significant discomfort associated with this preparation. We hypothesize the differences in clinic are a result of cytotoxicity effects of PEG. PEG is approved by the FDA for use in medical devices, and has been recognized for many years as a biocompatible/bioinert polymer but few studies have truly studied the short-term and long-term effects of high concentrations of PEG on multiple cell lines. We have developed a pH responsive hydrogel to control the release of PEG – reducing adverse effects associated with colonoscopy preparations. The hydrogels have been characterized using NMR, FTIR, and XPS to ensure chemical identity. Biocompatibility testing of exposure to increasing PEG concentrationsover a period of 3 hours, 6 hours, 12 hours, 24 hours, and 48 hours shows PEG is biocompatible to mammalian cell lines in low concentrations, and in fact, increases their growth and viability. At higher concentrations, however, PEG is cytotoxic to cells. Although it would be difficult to get to toxic levels of PEG in the body in a single dose, current uses of PEG should be re-evaluated due to possible adverse cumulative effects due to the cytotoxicity effects seen in vitro.