EVALUATION OF ENTERIC-COATED TABLET SENSITIVE TO PANCREATIC LIPASE .2. IN-VIVO EVALUATION

Plain tablets containing a model drug, sulfamethizole (SMZ), were coat ed with triolein (TO), trilaurin (TL) and ethylcellulose (EC). The bio logical behavior of the coated tablets (TOTL-Tab), which are pH indepe ndent and sensitive to pancreatic lipase, was investigated in humans. Results of the administration of the tablets with or without an antaci d, under fasting and non-fasting conditions, and at 0.5 h before and 0 .5 h after meals, were examined. A comparison of the in vivo behavior of SMZ after the administration of these tablets was done using the fo llowing data: the lag time of urinary excretion (U(lag)), the total ur inary recovery percentage (X(u)infinity), and the mean residence time after U(lag) (MRT(af). A typical pH-sensitive tablet coated by cellulo se acetate phthalate (CAP-Tab) was used as a reference. For the admini stration of a CAP-Tab alone, the U(lag) obtained under both the non-fa sting and fasting condition was longer than that of the plain tablet. However, U(lag) after the administration of a CAP-Tab with an antacid became considerably shorter. This lag time was about the same as that obtained from the plain tablet, regardless of food ingestion. The obta ined CAP-Tab MR T(af) and X(u)infinity values were not significantly d ifferent in comparison to the plain tablets. Under the non-fasting con dition, U(lag), MRT(af) and X(u)infinity of TOTL-Tab were not affected by the co-administration of an antacid, and these values were virtual ly the same as those obtained from a CAP-Tab without an antacid. The u rinary excretion data obtained after the administration of TOTL-Tab al one under fasting was analogues to the non-fasting case. When TOTL-Tab was co-administered with an antacid under fasting, the MRT(af) was th e much longer than that of the plain tablet, and the X(u)infinity was almost a half that of the plain tablet. These results suggest that TOT L-Tab is useful as an enteric release preparation sensitive to pancrea tic lipase in humans, except when antacids are taken under a fasting c ondition.