Studies on intestinal lymphatic absorption of drugs. I. Lymphatic absorption of alkyl ester derivatives and .ALPHA.-monoglyceride derivatives of drugs.

Abstract

Several alkyl ester derivatives or alpha-monoglyceride derivatives of 3H-labeled compounds, i.e. trimetoquinol, TA-594, acetaminophen, naproxen and nicotinic acid, were synthesized and administered orally to rats cannulated in the thoracic duct. The radioactivity appearing in 24 h-lymph was measured and analyzed by thin-layer chromatography. Most of the alpha-monoglyceride derivatives were absorbed via the intestinal lymphatic system, while the alkyl esters were very poorly absorbed. After oral administration of alpha-monoglyceride derivatives of labeled naproxen and nicotinic acid, the radioactive compounds found in the lymph were mainly monoglyceride, diglyceride and triglyceride analogues, while in plasma the main radioactive compound was the parent drug. It was concluded that alpha-monoglyceride derivatives of drugs were absorbed via the lymphatic system and transported into blood, yielding the parent drug in blood.