Abstract: Presystemic metabolism in intestine of bioactives such as phenylephrine is avoided by administering a subject (human or animal) the bioactive (e.g., phenylephrine) in combination with one or more inhibitors of sulfation (e.g., sulfotransferase enzymes aka SULTs). This can also be enhanced be co-administering inhibitors of monoamine oxidases aka, MAOs, and uridine diphosphate glucoronysl transferases, aka UGTs. Preferably the inhibitors are GRAS compounds. The one or more inhibitor compounds inhibit the enzymes responsible for rapid presystemic metabolism, thus allowing the bioactives (e.g., phenylephrine) to be more readily absorbed intact into the circulatory system.

Abstract: Compositions comprising one or more opioids and one or more inhibitors of uridine diphosphate glucuronosyl transferases (UGTs) are provided. The inhibitors decrease the presystemic metabolism of the one or more opioids, thereby increasing their bioavailability. The inhibitors are compounds that are designated as Generally Regarded as Safe (GRAS) and/or “Everything Added to Food” (EAF) and/or are dietary supplements. Methods of alleviating pain and of treating opiate addiction in a subject by administering the compositions are also provided.

Abstract: Presystemic metabolism in intestine of bioactives such as phenylephrine is avoided by administering a subject (human or animal) the bioactive (e.g., phenylephrine) in combination with one or more inhibitors of sulfation (e.g., sulfotransferase enzymes aka SULTs). This can also be enhanced be co-administering inhibitors of monoamine oxidases aka, MAOs, and uridine diphosphate glucoronysl transferases, aka UGTs. Preferably the inhibitors are GRAS compounds. The one or more inhibitor compounds inhibit the enzymes responsible for rapid presystemic metabolism, thus allowing the bioactives (e.g., phenylephrine) to be more readily absorbed intact into the circulatory system.

Abstract: Prodrugs comprising a lipophilic drug linked to a transport moiety that can be taken up by a fatty acid transporter are provided. The transport moiety comprises a lipid chain connected to a hydrophilic group (e.g. a carboxylic acid, a phosphate, or a sphingosine-like moiety). Due to the presence of the transport moiety, the prodrugs are substrates for endogenous fatty acid transporter systems. The transport moiety thus serves as a carrier or targeting moiety to facilitate uptake of the entire prodrug complex by endogenous fatty acid transporter systems, thereby moving the prodrug into cells and tissues where drug distribution and effects are desired. Hydrolysis of the chemical linkage between the lipid-like moiety and the lipophilic drug releases the drug in an active form within the cells or tissues.