A soluble and biodegradable material
The difference between solubility and biodegradability relies in the fact that a soluble material will just dissolve in the solvent (mainly water), without changing its constituents to organic ones (physical process). However, a biodegradable material will be transformed by microorganisms to organic elements (chemical process). The biodegradability of a material will depend on the surrounding conditions, for this reason, when biodegradability is claimed it is important to mention the time and under what conditions a material will biodegrade.
Even though some polymers claim to be soluble in water, its biodegradability is not confirmed by any means. On the contrary, CareTips® is a plastic free material according to REACH regulation. It is a soluble polymer, even in cold water. But also, its biodegradability has been tested: