02261nam a2200313Ia 4500 MX-MdCICY 20260521091506.0 CICY B-15829 Synthesis and characterization of putrescine-based poly(phosphoester-urethanes) Journal of BioMaterials Science, Polymer Edition, 4(5), p.529-543, 1993 A novel set of putrescine-based segmented polyurethanes was synthesized using 1,4-butane- diisocyante and phosphoester diols, and was characterized for its potential as a degradable biomaterial. These poly(phosphoester-urethanes)(PPU)were flexible polymers with ultimate tensile strength (UTS)from 2 to 3 MPa, elongations up to 80 per cent and tan ? near 0.15. The incorporation of phosphoester bonds in the backbone of the polymer by using bis(2-hydroxyethyl)phosphite (BGP)and bis(6-hydroxyhexyl)- phosphite (BHP)as chain extenders resulted in hydrolytic degradation which was evaluated in vitro. By varying the content of the phosphoester diol BGP, degradation rate, as followed by mass loss and GPC, could be modulated. Polymers based on the more hydrophobic monomer, BHP, showed slower degradation than corresponding BGP based polymers. Tensile properties of PPU-B2 after 22 days in vitro degradation show more than a 50 per cent drop in UTS and ultimate elongation, likely caused by void spaces left behind in the polymer after mass loss and swelling. The attachment of a drug, PAS, pendant to the phosphoester group of the PPU was demonstrated. PAS was linked via the spacer 4-hydroxybenzaldehyde, and free, intact drug was released in about 5 h from a thin film. ARTICLE CHEMICAL STRUCTURE CHEMISTRY DRUG DELIVERY SYSTEM SYNTHESIS AMINOSALICYLIC ACID P AMINOSALICYLIC ACID POLYURETHAN PUTRESCINE Dahiyat, B.I. Hostin, E. Posadas, E.M. Leong, K.W. https://drive.google.com/file/d/199wiKIbFUhG-kOttCyOcxkXZDTIEdIXc/view?usp=drivesdk Para ver el documento ingresa a Google con tu cuenta: @cicy.edu.mx Loc REF1 250602s9999 xx |||||s2 |||| ||und|d 25945 25945 0 0 Loc 0 0 F1 CICY CICY RE 2025-06-25 0 B-15829 2025-06-25 16:01:40 2025-06-25 REF1