Potential use of a megamolecular polysaccharide sacran as a hydrogel-based sustained release system.

A megamolecular polysaccharide sacran was newly extracted from cyanobacterium Aphanothece sacrum. Sacran has many preferable properties for transdermal application, e.g. a safe biomaterial, a high moisturizing effect, a formation of film and hydrogel. Additionally, it was recently discovered that sacran has an anti-inflammatory effect for atopic dermatitis model mice. In this study, in order to evaluate the feasibility of sacran-hydrogel as a novel sustained release system, we prepared a sacran-hydrogel containing 4-biphenyl acetic acid (BPAA, an acidic drug), prednisolone (PD, a neutral drug) or chlorpheniramine maleate (CPM, a basic drug), and performed the in vitro release studies. The sacran-hydrogel containing BPAA, PD or CPM provided a sustained release profile in accordance with a quasi-Fickian diffusion model. Furthermore, the release rate of drugs from sacran-hydrogels can be controlled by adjusting the concentration of aluminum chloride as a cross linker. These results suggest the potential use of sacran-hydrogel as a sustained release system for drugs.