Ntrimethyl chitosan chloride, a partially quaternised derivative of chitosan, which is soluble in neutral and basic environment, can be used as an absorption enhancer of oral peptide drugs.

It is implied by the transient absorption spectrum that, under neutral and acid conditions, 4-chlorophenol is first transformed into OH-adduct, and then dechlorinates through further reactions;

The reaction from Light-Adaptation form to Dark-Adaptation form of neutral red-regenerated purple membrane(PM)and the light absorption change of bound neutral red in regenerated PM were studied.