Excipient (pharmacologically inactive substance)
What is it?
Methyl methacrylate (C5H8O2) is used in the manufacture of resins and plastics, and as an enteric coating for tablet medications. Enteric coatings prevent stomach dissolution. Medicines that have an irritant effect on the stomach, such as aspirin or ibuprofen, can be enteric coated and will only dissolve in the small intestine. Methyl methacrylate monomers were also previously used in artificial nail (acrylic) products, but have now been removed by the FDA. However, no regulation specifically prohibits the use of methyl methacrylate monomer in cosmetic products. Acute toxicity is low, but methyl methacrylate an be irritating to the skin, eyes, and mucous membranes (lungs) in humans. An allergic response to skin exposure may develop, and respiratory symptoms such as chest tightness, shortness of breath, coughing, and wheezing may occur. Methyl methacrylate exists as a colorless liquid.
 Colorcon. Opadry® Enteric. Accessed February 21, 2015 at http://www.colorcon.com/literature/marketing/mr/Delayed%20Release/Opadry%20Enteric/Chinese/ads_opadry_enteric_94Series_aspirin_ver3_012009.pdf