Synthesis Of AMPS-Based Polymerizable Ionic Liquids And Drug Release Property Of Its Copolymeric Gels

Polymerizable room temperature ionic liquids (RTILs) were synthesized by neutralization of2-acrylamido-2-methyl-l-propane sulfonic acid (AMPS) and triethylamine (TEA) or imidazole (iMz). Co-polymeric gels based on such RTILs were synthesized by solution copolymerization; the swelling properties in water and organic liquids of the gels were investigated. By using chloramphenicol as a model drug, uploading and release of water insoluble drugs onto Poly(AMPS-TEA-co-AAm) gels were investigated.Synthesis of AMPS-based RTILs were investigated. By using acetone as a solvent, AMPS was neutralized with TEA and iMz followed by evaporation of the solvent, to give AMPS-TEA and AMPS-iMz RTIL, respectively. The two RTILs were characterized with FT-IR and1H-NMR. DSC data showed the glass transition temperature was-59.4?for AMPS-TEA, and34?for AMPS-iMz.A series of co-polymeric gels based on AMPS-TEA and AMPS-iMz were synthesized, their swelling properties in water and a series of organic liquids were investigated. Firstly, Co-polymeric gels of Poly(AMPS-TEA-co-AAm) were synthesized by co-polymerizing AMPS-TEA with acrylamide (AAm) in aqueous solutions using N,N'-methylenebisacrylamide (MBAm) as a crosslinker, and ammonium persulfate (APS) as an initiator. The results showed that Poly(AMPS-TEA-co-AAm) were transparent and glassy gels. Poly(AMPS-TEA-co-AAm) gels exhibited superabsorbency in both water and a series of organic liquids. There was no obvious relationship between absorbency and dielectric constant of the liquids being absorbed by the gels. Poly(AMPS-TEA-co-AAm) gels exhibited good liquids retaining property; the liquids being absorbed were kept without spillage under static pressure and centrifugation.The swelling property of Poly(AMPS-TEA-co-AAm) was seriously influenced by AAm content in the gels. Poly(AMPS-TEA-co-AAm) did not show any absorbency if the feeding ratio of AAm was less than15wt%; and Poly(AMPS-TEA-co-AAm) can swell in water while can not swell in any organic liquids if the feeding ratio of AAm was more than95wt%.Co-polymeric gels of AMPS-iMz and AAm or sodium acrylic acid (AANa) were synthesized by aqueous solution copolymerization; their swelling property were investigated. The results showed that the absorbency of Poly(AMPS-iMz-co-AAm) was186g/g and267g/g for water and DMSO respectively; and Poly(AMPS-iMz-co-AAm) can not swell in other organic liquids. Poly(AMPS-iMz-co-AANa) can only swell in water. Co-polymeric gels of AMPS-iMz and methylmethylate (MMA), butylmethylate (BMA) were synthesized respectively by solution copolymerization using benzene as a solvent, and divinylbenzene (DVB) as a crosslinker. Both poly(AMPS-iMz-co-MMA) and poly(AMPS-iMz-co-BMA) can not swell in water; while they can swell in benzene, toluene, cyclohexane, butanone and methylmethylate. There was no obvious relationship between absorbency and dielectric constant of the liquids being absorbed by poly(AMPS-iMz-co-MMA) and poly(AMPS-iMz-co-BMA) gels.The mechanism of superabsorbency for water and a series of organic liquids of co-polymeric gels based on AMPS-based ionic liquids were investigated. It was suggested that the reasons of superabsorbency for organic liquids were compatibility of macromolecular chains and the solvents, and the ionic liquids being completely made of ions.By using chloramphenicol as a model drug, uploading of water insoluble drugs on the xerogels of Poly(AMPS-TEA-co-AAm) was investigated by swelling the xerogel of Poly(AMPS-TEA-co-AAm) in the drug solution followed by removing the solvent to give drug-polymer conjugate using water and alcohols as a solvent, respectively.. The results showed that there was no obviously difference between absorbency in pure solvents and chloramphenicol solutions; and chloramphenicol concentration of the solutions has no influence on the absorbency. The drug loading capacity was decided by the concentration of chloramphenicol in the solutions.The drug-polymer conjugate was characterized with XRD, and the results showed that chloramphenicol was molecularly dispersed in the networks of the gels if the drug uploading was low; and chloramphenicol was crystal in the networks of the gels if the drug uploading was high.The chloramphenicol release from the xerogel of Poly(AMPS-TEA-co-AAm) was investigated in distilled water, physiological saline, and phosphate buffer solution (PBS). The results showed the release process of chloramphenicol included swelling of the xerogel, dissolution of the drug in water, and diffusion of the drug from the gels to the swelling media. The xerogel of drug-polymer conjugate swelled quickly in distilled water, physiological saline, and PBS; and the absorbency for the swelling media was decided by the drug uploading content. In distilled water, physiological saline, and PBS, the drug release ratio was40-90%and did not change after60-120min release. For more drug uploaded onto the xerogel, the drug release ratio was less.