1 Pharmaceutical Design and Drug Delivery, Department of Pharmacy, Faculty of Health and Medical Sciences, Københavns Universitet2 IKVH Fysiologi og ernæring samt pelsdyrfarmen, Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, Københavns Universitet3 Department of Pharmacy, Faculty of Pharmaceutical Sciences, Københavns Universitet4 Department of Pharmaceutical Technology, Faculty of Pharmacy, National and Kapodistrian University of Athens5 Pharmaceutical Design and Drug Delivery, Department of Pharmacy, Faculty of Health and Medical Sciences, Københavns Universitet6 Department of Pharmacy, Faculty of Pharmaceutical Sciences, Københavns Universitet
OBJECTIVES: Studies on the characterization of ascending colonic fluids are scarce, limited to physicochemical characterization of their composition, and little is known for the morphology of the produced colloidal phases. In an attempt to gain insights for their structure at the ultrastructural level, samples from the lumen of ascending colon were collected from patients with ulcerative colitis in remission. METHODS: After ultracentrifugation, the supernatants of two samples (one with high and one with low cholesterol level) were visualized by means of cryogenic transmission electron microscopy. KEY FINDINGS: In the supernatants with high cholesterol content, micellar-like structures, bilayer fragments, open vesicles, and uni-, bi- and trilamellar vesicles were abundant. In addition, crystals of cholesterol were frequently observed. In contrast, in the sample with low cholesterol content, oily solids, plates of cholesterol monohydrate and elongated structures were present. Few unilamellar vesicles were occasionally visualized. CONCLUSIONS: The current study gives direct evidence, for the first time, of the existence of 'remnants' of lipolytic products in the fasted ascending colon. The impact of these structures to colonic absorption of drugs is an open question.
Journal of Pharmacy and Pharmacology, 2013, Vol 65, Issue 10, p. 1482-7