WATER-SOLUBLE POLYAMIDES AS POTENTIAL-DRUG CARRIERS .6. SYNTHESIS OF AMINE-FUNCTIONALIZED AND CARBOXYL-FUNCTIONALIZED CARRIER POLYMERS BY HIGH-TEMPERATURE SOLUTION POLYMERIZATION IN POLYPHOSPHORIC ACID

Hydrophilic polyamides containing amino or carboxyl groups in the repe at units suitable for drug binding are synthesized by polycondensation of aliphatic dicarboxylic acids, including succinic acid, iminodiacet ic acid, and ethylenediaminetetraacetic acid (reacting as a difunction al monomer in these polymerizations), with diamines, such as diethylen etriamine, 1,2-bis(3-aminopropylamino)ethane, and the two hydrosolubil izing poly(ethylene oxide) derivatives, alpha,omega-bis(2-aminopropyl) poly(ethylene glycol) 800 (Jeffamine ED-900) and alpha,omega-bis)2-ami nopropyl)poly(ethylene glycol) 1900 (Jeffamine ED-2001). The reactions are conducted in polyphosphoric acid medium at the optimal temperatur e range of 150-165-degrees-C. The product polymers, fractionated by aq ueous-phase dialysis in 12 000-14 000 molecular-mass cut-off membrane tubing, are isolated by freeze-drying. Yield data, ranging from 1% to nearly 40% for the material so fractionated, indicate low propensity f or polycondensation under these conditions for the volatile diethylene triamine monomer, and only moderately better performance for the therm ally labile Jeffamines, yet satisfactory polymerization behaviour for the bis(aminopropylamino)ethane. The microanalytically and spectroscop ically characterized polyamides fulfil the biomedically important requ irement of solubility in water; inherent viscosities in this medium ar e in the approximate range of 5-15 ml.g-1. The drug-anchoring capabili ties of these polymers will be the subject of forthcoming publications .