Low molecular weight quaternised chitosan (I): synthesis and characterisation.

For a better understanding of the behaviour of macromolecules in vitro and in vivo, their structural and chemical properties that may be influential as experimental variables need to be characterised. N-Trimethyl chitosan chloride and N-triethyl chitosan chloride have been synthesised from chitosan to increase the solubility range of these polymers. However, little is known about the effect of the degree of quaternisation, molecular weight, viscosity and different substitution groups on the polymer's ability to enhance the transport of large hydrophilic compounds, such as peptide and protein drugs, across intestinal and nasal epithelia and on their toxicity profile. This study describes the synthesis of various quaternised chitosan polymers from low and medium molecular weight chitosan. These polymers were characterised to determine if any relationships between their degree of quaternisation, molecular weight and viscosity could be found which will determine their behaviour as absorption enhancers in future studies.