This one is related to oxidation.
"BACKGROUND
Mixed omega-3 fatty acid esters are typically encapsulated in type 2a gelatin capsules containing gelatin (.about.43.4%), glycerol (.about.20%) and water (.about.36.6%) and do not experience stability problems throughout their shelf life. While chemically modified gelatins such as succinated/succinylated gelatin have been used to encapsulate reactive fill ingredients, such gelatin is not approved for use in the U.S. and other markets.
SUMMARY
We have unexpectedly found that high purity eicosapentaenoic acid (EPA) is more susceptible to oxidative degradation than mixed omega-3-acid ethyl esters. In various embodiments, the invention provides pharmaceutical compositions comprising a fatty acid or a derivative thereof in a capsule shell that resists, hinders, attenuates, or prevents oxidation of the fatty acid or fatty acid derivative, for example to a greater extent than is provided by a standard type IIa capsule shell. In a related embodiment, the fatty acid comprises eicosapentaenoic acid (EPA) or a derivative of EPA, for example ethyl eicosapentaenoate (ethyl-EPA or E-EPA). In another embodiment, the fatty acid comprises ultra-pure EPA."