In order to obtain feasibility data regarding the possibility of using
chondroitin sulfate (CS) in an anti-
cancer drug delivery system, CS was chemically modified by a one-step process with
acetic anhydride. Although 3 samples with different degrees of acetylation were synthesized, only the sample with the highest degree of acetylation (AC-CS3) was tested as a
nanogel because the others (AC-CS1 and 2) dissolved in distilled water (DW) in the test range (1-10 mg/ml). The AC-CS3
nanogel was characterized by fluorescence probe and dynamic light scattering (DLS) techniques. Its critical aggregation concentration (CAC) was <2.0 x 10(-2) mg/ml at 25 degrees C. The partition equilibrium constant, K(v), of the
nanogel (7.88 x 10(5)) was similar to that of polymeric
micelles, which means that the acetyl group may act as a hydrophobic core controlling pharmacokinetic behavior. The higher surface charge value in the
nanogel, above - 40 due to carboxyl and
sulfate groups in CS, explains its good stability. The anticancer
drug doxorubicin (DOX) loading efficiency of the AC-CS3
nanogel was also superior, at above 90%. Changes in the size of the polydispersion index (PDI) of
nanogels loaded with DOX over a 3-week period were negligible. The
nanogels interacted with HeLa cells and were internalized together with the entrapped
drug within the cytoplasm, probably via an endocytic mechanism exploited by
sugar receptors. Based on these results, the AC-CS3
nanogel is expected to prove useful as an anti-
cancer drug carrier for
chemotherapy.