Chitosan-functionalised poly(2-hydroxyethyl methacrylate) core-shell microgels as drug delivery carriers: salicylic acid loading and release

Natshisa Mahattanadul a,b, Panya Sunintaboon a,b*, Piyawan Sirithipa and Patoomratana Tuchinda a,b

a Department of Chemistry, Faculty of Science, Mahidol University, Bangkok, Thailand;

b Center of Excellent for Innovation in Chemistry (PERCH-CIC), Bangkok, Thailand

This work presents the evaluation of chitosan-functionalised poly(2-hydroxyethyl methacrylate) (CS/ PHEMA) core-shell microgels as drug delivery carriers. CS/PHEMA microgels were prepared by emulsifierfree emulsion polymerisation with N,N0 -methylenebisacrylamide (MBA) as a crosslinker. The study on drug loading, using salicylic acid (SA) as a model drug, was performed. The results showed that the encapsulation efficiency (EE) increased as drug-to-microgel ratio was increased. Higher EE can be achieved with the increase in degree of crosslinking, by increasing the amount of MBA from 0.01 g to 0.03 g. In addition, the highest EE (61.1%) was observed at pH 3. The highest release of SA (60%) was noticed at pH 2.4, while the lowest one (49.4%) was obtained at pH 7.4. Moreover, the highest release of SA was enhanced by the presence of 0.2 M NaCl. The pH- and ionic-sensitivity of CS/PHEMA could be useful as a sustained release delivery device, especially for oral delivery.

Keywords: Chitosan; core-shell; drug delivery; microgel; poly(2-hydroxyethyl methacrylate); salicylic acid

For more details: Journal of Microencapsulation, 33:6, 563-568.