Viscosity Changes Using Semi-solidifying Materials and the Dissolution Behavior of a Drug in Enteral Nutrition

Abstract

Semi-solid enteral nutrient administration has recently been performed at many institutions. Drugs are mixed with semi-solidified pure water and administered, but the drug dissolution pattern may alter depending on the type of semisolidifying material. We investigated differences in viscosity changes due to the characteristics of semi-solidifying materials and dissolution behavior of a drug mixed with semi-solidified pure water. Pure water preparations semi-solidified by 4 semi-solidifiers were adjusted to about 8,000 mPa･s, and viscosity changes at 25℃ and 37℃ were measured using a cone-plate rotational viscometer. In addition, gliclazide tablets used as a model drug were ground or mixed with the semi-solidified pure water preparations and subjected to dissolution tests employing the paddle method under the conditions of: dissolution time, 90 minutes; and test solution pH 1.2 and 6.8. The pure water preparations semi-solidified by the 4 semi-solidifiers (Kanten Cook Ⓡ (agar), Gelatin Leaf, Toromeiku Ⓡ SP, Tsururinko) showed non-Newtonian flow (except Gelatin Leaf at 37℃), and viscosity changes varied among the semi-solidifiers. In the dissolution tests, the dissolution rates of gliclazide mixed with pure water semi-solidified by Kanten Cook Ⓡ and Gelatin Leaf showed elution patterns similar to that of ground tablets, but those mixed with pure water semi-solidified by Toromeiku Ⓡ SP and Tsururinko were about half of these rates. The viscosity change and delay in drug dissolution were observed depending on the type of semi-solidifier.