Assadang Polnok. Evaluation of intestinal absorption of desmopressin using drug delivery system based on superporous hydrogel . Doctoral Degree(Pharmaceutics). Mahidol University. : Mahidol University, 2005.
Evaluation of intestinal absorption of desmopressin using drug delivery system based on superporous hydrogel
Abstract:
The main goal of this study was to investigate and modify a drug delivery
system based on superporous hydrogel (SPH) to improve the intestinal absorption of
the peptide drug desmopressin. N-trimethyl chitosan chloride (TMC), a chemically
modified derivative of chitosan, is an absorption enhancer for peptide drugs across
mucosal epithelial. TMC was synthesized by reductive methylation of chitosan with
methyl iodide in an alkaline environment at elevated temperature. The number of
methylation process steps and the alkali used in the process were shown to affect the
degree of quaternization of the primary amino group and methylation of 3- and 6-
hydroxyl groups. The swelling properties and mechanical strength of SPHs were
affected by addition of the disintegrant AcDiSol. This disintegrant reduced the
swelling degree of the polymer to 80%, but the swelling rate was increased.
Additionally, AcDiSol increased the mechanical strength of the SPHs. The release
profile of desmopressin was investigated by changing the composition of excipients in
the formulations. In comparison with the negative control, the transport of
desmopressin across the intestinal mucosae ex vivo was enhanced 4- and 6-fold by
applying SPH, with AcDiSol, in the absence and presence of TMC , respectively.
Pharmacokinetic parameters of desmopressin after administration in oral drug delivery
system based on SPH were studied in pigs. The absolute bioavailability of
desmopressin in SPH without and with TMC was 0.42% and 0.63%, respectively