| 摘要 |
A polyurethane (I) of 1000 to 100,000 in average molecular weight, comprising plural segments, which are each structural units of A-B, A-C and A-D of the formulae: <IMAGE> A-B <IMAGE> A-C and <IMAGE> A-D the proportion of the said segments of A-B, A-C and A-D, i.e. x:y:z is in the molar ratio 0.01 to 0.8:0 to 0.80:0 to 0.99, provided that the sum of x, y and z is 1.0; each segment being produced by combining with repeat units of A, B, C and D of the formulae: <IMAGE> A -aza-, B ZR2Z and C OR3O; D wherein R1 is a skeleton of a diisocyanate and the three R1's in each of segments A-B, A-C and A-D can be the same or different; aza is a group of the formula: <IMAGE> (i) <IMAGE> (ii) wherein Y1 and Y2 which can be the same or different, are oxygen, imino(-NH-) or a group of the formula: *R6-O, *R6-NH, O-R6-O, *NHCO-R6-NH or *CONH-R6-NH; wherein R6 is alkylene and an atom or the end of the group, marked by * is bonded to phenyl ring; R4 and R5 each are, independently, hydrogen, halogen, nitro or phenyl; R2 is polyalkylene glycol residue; Z is oxygen or imino and the two Z's are the same; R3 is alkylene or a group of the formula: <IMAGE> wherein R7 and R8 which can be the same or different, are alkylene; and R9 is alkyl; each segment of the polyurethane being contained in the aforementioned proportion of x, y and z, is combined by block-type, random-type or a combination thereof, is degraded specifically in the large intestine. Therefore, by using the polyurethane as pharmaceutical adjuvants, the medicament can be delivered specifically to the large intestine and at a high concentration with hardly any degradation and absorption in the small intestine, after oral administration.
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