The Influence of Chitosan on in Vitro Properties of Eudragit RS Microspheres.

Abstract

Eudragit RS microspheres containing chitosan hydrochloride were prepared by the solvent evaporation method using acetone/liquid paraffin solvent system and their properties were compared with Eudragit RS microspheres without chitosan, prepared in our previous study. Different stirring rates were applied (400-1200 rpm) and drug content, Higuchi dissolution rate constant, surface and structure characteristics of the microspheres were determined for each size fraction. An increase in average particle size with a reduction of stirring rate appeared in limited interval in both series. The average particle size of microspheres without chitosan, prepared at the same stirring rate, was smaller. Pipemidic acid content increased with increasing fraction particle size, but not with increasing stirring rate as it was observed for microspheres without chitosan. We presume that high pipemidic acid content in larger microspheres is a consequence of cumulation of undissolved pipemidic acid particles in larger droplets during microspheres preparation procedure. Pipemidic acid release was faster from microspheres with chitosan and no correlation between Higuchi dissolution rate constant and stirring rate or fraction particle size was found, though it existed in the system without chitosan. Structure and surface characteristics of microspheres observed by scanning electron microscope (SEM) were not changed significantly by incorporation of chitosan. But in contrast with microspheres without chitosan, the surface of chitosan microspheres was more porous after three hours of dissolution. It is supposed that the influence of particle size fraction and stirring rate on release characteristics is expressed to a great extent through porosity and indirectly through total effective surface area, but the incorporation of highly soluble component i.e. chitosan salt hides these effects on drug release. In conclusion, changes in biopharmaceutical properties due to varying stirring rate and fraction particle size exhibited the same direction as those reported for the microspheres without chitosan, although they are less expressed because of increased experimental variability, likely caused by chitosan.

Development and Optimization of Acriflavine-Loaded Polycaprolactone Nanoparticles Using Box–Behnken Design for Burn Wound Healing Applications

“…The stirring speed (X2) showed a slightly negative impact on the %EE. An increase in stirring speed (X2) led to a decrease in %EE, which is accordance with Bozena et al’s work, where they stated that increases in stirring speed will decrease the drug content of particles [ 44 ]. Similarly, JK Patel’s study also showed a decrease of %EE with an increase of stirring speed, which is an accordance with our results [ 45 ].…”

Brimonidine Tartrate–Eudragit Long-Acting Nanoparticles: Formulation, Optimization, In Vitro and In Vivo Evaluation

“…Eudragit RL 100 (ERL 100) and Eudragit RS 100 (ERS 100) are inert polymeric resin copolymers of poly(ethacrylate, methylmetacrylate and chlorotrimethyl ammonioethyl methacrylayte) containing an amount of quaternary ammonium groups, ranging between 4.5-6.8% and 8.8-12.0% for RS and RL, respectively. Several reports are cited in the literature on the application of ERS 100 and ERL 100 as polymeric carriers for the delivery of drugs (30)(31)(32)(33). Most of them are for the entrapment of water-insoluble/lipophilic drugs.…”

Designing and evaluation of urea microcapsules in vitro to improve nitrogen slow release availability in rumen

“…We are not aware of any published reports on the urea release kinetics for microencapsulated systems using Eudragit RS100®. Eudragit RS100® has been previously studied as an encapsulating agent for drug or selenium delivery . The results obtained in this work for the CSU and ACU microcapsule ammonia‐N release kinetics were favorable, showing an ammonia‐N concentration of 4 mg dL −1 after the first hour.…”

“…Although the control group showed accumulation of ammonia‐N in the media, this will not happen in vivo because ammonia‐N is absorbed through the rumen wall into the bloodstream, preventing its accumulation in the rumen fluid . The system consisting only of urea and Eudragit RS100® kept ammonia‐N levels under 8.5 mg dL −1 , perhaps because, during this period, bacteria did not have rapid access to urea as a consequence of being incorporated into the polymerized, granulated structure …”

“…However, some studies show little or no benefit of these nitrogenous products . Several microencapsulated systems have been developed to deliver minerals; for example, pH‐dependent polymers such as Eudragit RS100® are already used for encapsulating drugs for controlled delivery in ruminants . In this study, we compared urea encapsulation methods to design a microencapsulation system able to produce microcapsules with a controlled slow and steady urea release into the rumen to prevent intoxication.…”