| Abstract: | Nicotinic acid was shown to be rapidly absorbed from the gastrointestinal tract but also rapidly eliminated from the blood stream. Administration of nicotinic acid was therefore associated with large fluctuations of nicotinic acid concentration in the plasma. Two alternative ways of maintaining a moderate but more constant increase of the nicotinic acid concentration in the blood were studied. One way was to give nicotinic acid as a “sustained release” preparation. Nicotinic acid in enterocoated tablets with dissolution times of 2 hrs (in simulated intestinal juice), induced only an irregular and transitory increase of the plasma nicotinic acid concentration after 5 hrs and in some subjects only a reduction in plasma FFA. Enterocoated tablets with a dissolution time of 4 hrs were ineffective. Nicotinic acid is a weak acid and as such is poorly absorbed from the more distal parts of the digestive tract. Therefore the biological prerequisites for this alternative method were not so good. The second alternative method studied was to give a nicotinic acid ester which would continuously release nicotinic acid in the body. The nicotinic acid ester used (pentaerythritol tetranicotinate, perycit®, Bofors) given in an oral dose of 1 g, was found to give a moderate but consistent and prolonged increase in the free nicotinic acid concentration and a consistent decrease in the FFA-level of plasma with a moderate flush. Nicotinic acid in ordinary tablets and in an equivalent dose induced a considerably more pronounced flush and a somewhat larger reduction in plasma FFA which however was of shorter duration. The decrease was accompanied by a secondary and prolonged elevation of the plasma FFA concentration. This secondary increase was not observed in the experiments with pentaerythritol tetranicotinate. The possible importance of these differences from a pharmacotherapeutical point of view is discussed. |
