Pectin-based microspheres for colon-specific delivery of vancomycin.
OBJECTIVE
The aim of this study was to describe a colon-specific delivery system based on pectin hydrogels formed by complexation with chitosan.


METHODS
Hydrogels were prepared at different weight ratios (4:1, 7:1, 10:1; pectin/chitosan), loaded with vancomycin hydrochloride (2:1, 4:1; polymer/drug weight ratio) and collected by spray-drying. The microspheres obtained were characterized in terms of morphology, swelling behaviour, mucoadhesive properties and drug loading efficiency. The influence of different pectin/chitosan hydrogels on the release behaviour of microspheres at pH 2.0, 5.5 and 7.4 were evaluated in vitro with and without pectinolytic enzyme.


RESULTS
The results showed that water uptake was increased by raising the environmental pH (from 2.0 to 7.4) and the pectin/chitosan weight ratio, while drug availability was increased by raising the environmental pH (from 2.0 to 7.4) and decreased by raising the pectin/chitosan weight ratio. In the presence of pectinase, the glycoside bonds of pectin were degraded and a considerable amount of drug was released in a short time.


CONCLUSIONS
This study suggested that pectin/chitosan microspheres were able to limit the release of vancomycin under acidic conditions and release it under simulated colonic conditions, confirming their potential for a colon-specific drug delivery system.
Bigucci
Federica
F
Department of Pharmaceutical Sciences, Bologna University, Bologna, Italy. federica.bigucci@unibo.it
Luppi
Barbara
B
Monaco
Libera
L
Cerchiara
Teresa
T
Zecchi
Vittorio
V
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D001682:Biological Availability; D048271:Chitosan / Q000737:chemistry; D003106:Colon / Q000378:metabolism*; D016503:Drug Delivery Systems / Q000379:methods*; D005612:Freeze Drying / Q000379:methods; D006801:Humans; D020100:Hydrogels / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010368:Pectins / Q000737:chemistry*; D011096:Polygalacturonase / Q000737:chemistry / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D013678:Technology, Pharmaceutical / Q000379:methods; D014640:Vancomycin / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D014867:Water / Q000737:chemistry / Q000378:metabolism
D000900:Anti-Bacterial Agents; D020100:Hydrogels; D014867:Water; D014640:Vancomycin; D010368:Pectins; D048271:Chitosan; D011096:Polygalacturonase