Investigation of a novel thermogelling hydrogel for a versatility of drugs delivery.

The P(CL-PDO)-PEG-(P(CL-PDO)(PECP) copolymer hydrogel is an attractive thermogelling material for practical applications due to the fast dissolution of the copolymer in water and good stability of the resultant sol solution that is beneficial for guest matter mixing. In this paper, the degradation properties and drug release behavior of the hydrogel loaded with various types of drugs were evaluated. The integrity of the PECP hydrogel could preserve for 2 weeks and became viscous liquid after degradation time of 21 weeks. With the degradation time, both the molecular weight and weight loss of the hydrogel decreased gradually. NMR analysis of the degraded products indicated that the chain breaking of the copolymer mainly occurred within the sequence structures of PDO-PDO or PDO-PCL, implying the acceleration effect of PDO unit to the degradation of hydrogel. Three distinct types of drugs including small molecular hydrophobic, small molecular hydrophilic and hydrophilic macromolecular drugs were loaded into the PECP hydrogel to evaluate their release profiles. The result showed that the releasing periods for macromolecular protein or hydrophobic drug were extended to more than one month. Since these two types of drugs are loaded within different regions of the hydrogel due to their different hydrophobic/hydrophilic nature, the PECP hydrogel is expected to develop injectable system loaded with a versatility of drugs or guest matter for synergetic effect. [ABSTRACT FROM AUTHOR]