u can go for polymeric vesicles of chitosan.

which involve step 1.chtosam attach to salt of lauric,myristic, palmitic ot stearic acid like pendant.which form vesicle.u can use carbopol of diffrent grade or other 3-D gelling agents.which is biocompatible and biodegradable.

The polyanion dextran sulfate (DEX) has been used to mask the positive charge of doxorubicin for encapsulation into positively charged chitosan. Using ionotropic gelation with sodium tripolyphosphate, Janes et al. prepared doxorubicin-loaded chitosan nanoparticles incorporating DEX. The addition of DEX yielded about 20% doxorubicin encapsulation efficiency (EE) into chitosan.

A similar study that utilised DEX to first couple doxorubicin into a conjugate before encapsulating it into chitosan hydrogel nanoparticles through a reverse microemulsion method with surfactant reported the potential of doxorubicin–DEX chitosan nanoparticles in vivo

http://onlinelibrary.wiley.com/doi/10.1211/jpp.61.02.0001/full

thnx ali

but i want to make a labile covalent bond between dox and chitosan backbone (for example schiff-base bond).