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Indomethacin-containing interpolyelectrolyte complexes based on Eudragit® E PO/S 100 copolymers as a novel drug delivery system
Potential applications of a novel system composed of two oppositely-charged (meth)acrylate copolymers, Eudragit® ЕРО (EPO) and Eudragit® S100 (S100), loaded with indomethacin (IND) in oral drug delivery were evaluated. The particles based on drug-interpolyelectrolyte complexes (DIPEC), (EPO-IND)/S100, were prepared by mixing aqueous solutions of both copolymers at fixed pH. Particles of drug-polyelectrolyte complex (DPC), (EPO-IND) have a positive zeta potential, pointing to the surface location of free EPO chains and IND bound to EPO sequences. The formation and composition of both DPC and DIPEC were established by gravimetry, UV-spectrophotometry, capillary viscosity and elemental analysis. The structure and solid state properties of the formulated DIPEC were investigated using FTIR/NIR, Raman spectroscopy, XRPD and modulated DSC. DIPEC is a chemically homogenous material, characterized by a single Tg. DIPEC have an IR absorption band at 1560 cm−1, which can be assigned to the stretching vibration of the carboxylate groups (S100, IND) that form ionic bonds with the dimethylamino groups of EPO. XRPD, NIR and Raman-shifts confirm that during the preparation of this formulation, IND is converted into its amorphous form. The release of IND from DPC EPO/IND (3:1) and DIPEC EPO/L100/IND (4.5:1:1) is sustained and is completed within 7 hours under GIT mimicking conditions. However, S100 within DIPEC makes the release process slower making this system suitable for colon-specific delivery. Finally, DPC and DIPEC with indomethacin were used to prepare tablets, which can be potentially used as oral dosage forms for their slower indomethacin release in case of DIPEC which could be suitable for sustained delivery
Enteric shell-core microparticles production by coupling ultrasonic atomization and polyelectrolytes complexation
Enteric shell-core microparticles, based on
polyelectrolyte complexes between the natural
biopolymer sodium alginate and the (meth)acrylate
copolymers Eudragit®, were produced to encapsulate the
gastrolesive drug indomethacin. The complexation of
polyelectrolytes together with the ultrasonic atomization,
used to produce fine droplets based on alginate ingredient,
can be performed using mild conditions, aqueous
solutions, in absence of organic solvents and chemical
crosslinkers, therefore this approach proves to be
convenient if compared to traditional method
Hydrophilic drug encapsulation in shell-core microcarriers by two stage polyelectrolyte complexation method
In this study a protocol exploiting the combination of the ultrasonic atomization and the complexation
between polyelectrolytes was developed to efficiently encapsulate a hydrophilic chemotherapeutic agent
essentially used in the treatment of colon cancer, 5-fluorouracil, in enteric shell-core alginate-based
microcarriers. The atomization assisted by ultrasound allowed to obtain small droplets by supplying low
energy and avoiding drug degradation. In particular microcarriers were produced in a home-made
apparatus where both the core (composed of alginate, drug, and Pluronic F127) and shell (composed of
only alginate) feed were separately sent to the coaxial ultrasonic atomizer where they were nebulized
and placed in contact with the complexation bulk. With the aim to obtain microstructured particles of
alginate encapsulating 5-fluorouracil, different formulations of the
first complexation bulk were tested;
at last an emulsion made of a calcium chloride aqueous solution and dichloromethane allowed to reach
an encapsulation efficiency of about 50%. This result can be considered very interesting considering that
in literature similar techniques gave 5-fluorouracil encapsulation efficiencies of about 10%.
Since a single complexation stage was not able to assure microcarriers gastroresistance, the
formulation of a second complexation bulk was evaluated. The solution of cationic and pH-insoluble
Eudragit1 RS 100 in dichloromethane was chosen as bulk of second-stage complexation obtaining good
enteric properties of shell-core microcarriers, i.e. a 5-FU cumulative release at pH 1 (simulating gastric
pH) lower than 35%. The formation of interpolyelectrolyte complex (IPEC) between countercharged
polymers and the chemical stability of 5-FU in microcarriers were confirmed by FTIR analysis, the
presence of an amorphous dispersion of 5-FU in prepared microparticles was also confirmed by DSC.
Finally, shell-core enteric coated microcarriers encapsulating 5-fluorouracil were used to prepare tablets,
which can be potentially used as oral administration dosage systems for their 5-fluorouracil slower
release