Mucosal drug delivery using cellulose derivatives as a functional polymer.

In order to develop nasal powder preparations with higher bioavailability for peptide delivery, the effect of a combination of hydroxypropyl cellulose (HPC) and microcrystalline cellulose (MCC) used as base materials and microenvironment for the drugs in the preparations was examined. Significant enhanced absorption of leuprolide, calcitonin and FITC-dextran was attained by the addition of a small amount of HPC to MCC. It is suggested that MCC works as an absorption enhancer by causing a locally high concentration of drugs in the vicinity of the mucosa surface. On the other hand, HPC works to increase retention of drugs on the nasal mucosa due to its gel-forming property. In comparison to the powder mixtures of MCC and HPC in which drugs were distributed to the MCC or HPC, selective distribution of drugs to MCC is shown to be a critical factor for enhancing nasal absorption. These results showed that the microenvironment of drugs in the functional base material could critically affect the nasal absorption of drugs.