Drug release modification by interpolymer interaction between countercharged types of Eudragit® RL 30D and FS 30D in double-layer films

Interpolymer interactions between the countercharged methacrylate copolymers Eudragit® RL 30D (polycation) and Eudragit® FS 30D (polyanion), were investigated in conditions mimicking the gastrointestinal environment. The formation of inter-macromolecular ionic bonds between Eudragit® RL 30D and Eudragit® FS 30D was investigated using FT-IR spectroscopy and modulated DSC. The FT-IR spectra of the tested polymeric matrices are characterized by visible changes in the observed IR region indicating the interaction between chains of two oppositely charged copolymers. A new band at 1570 cm-1 appeared which was assigned to the absorption of the carboxylate groups that form the ionic bonds with the quaternary ammonium groups. Moreover, while increasing the pH values from pH 5.8 to 7.4, a decrease of the intensity of the band at 960 cm-1 (quaternary ammonium group vibration) was observed. All binary mixtures were characterized by the presence of only one and narrow Tg, pointing to sample homogeneity, because of the compatibility of components. As a result of electrostatic interaction between the copolymer chains during swelling, the resulting Tg is decreased significantly and was dependent on the quantity of copolymers present in the structure of polycomplexes formed. Overall, the interaction between countercharged copolymers during passage in gastrointestinal tract can strongly modify the release profile of the model drug diclofenac sodium. © 2012 Elsevier B.V. All rights reserved

Structural transformations during swelling of polycomplex matrices based on countercharged (meth)acrylate copolymers (Eudragit® EPO/Eudragit® L 100-55)

With a view to the application in oral controlled drug delivery systems (DDS), the design of new interpolyelectrolyte complexes (IPECs) between countercharged types of Eudragit® EPO (EPO) and Eudragit® L 100-55 (L100-55) was investigated. The formation and composition of four new IPECs between EPO and L100-55 were established by elementary analysis. The structure of the synthesized IPEC was investigated using FTIR spectroscopy and modulated-temperature differential scanning calorimetry. The binding ratio of a unit molecule of EPO with L100-55 was found to range between 1:2.75 (Z = 0.36) and 1:0.55 (Z = 1.81) while increasing the pH value from 5.5 to 7.0. As a result of electrostatic interaction between the copolymer chains, the glass transition temperature of the IPEC increased significantly. A large pH-sensitive swelling behavior was observed for different structures of the IPECs. The outcome of swelling and diclofenac sodium release from the polycomplex matrices confirm that they have great potential to be used as a controlled DDS in specified regions of gastrointestinal tract. © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

Interpolyelectrolyte complexes of Eudragit® e PO with sodium alginate as potential carriers for colonic drug delivery: Monitoring of structural transformation and composition changes during swellability and release evaluating

Background: With a view to the application in oral colon drug delivery systems, swelling and release behavior of synthesized interpolyelectrolyte complexes (IPEC) between sodium alginate and Eudragit® EPO were investigated. Method: The microenvironmental changes in IPECs structure as a function of pH during swellability testing were investigated using FT-IR spectroscopy and elementary analysis. Results: All samples of IPECs (Z 0.661.25) during swelling were transformed to a similar structure with approximately the same composition. The release of the model drug diclofenac sodium was significantly delayed from matrices made up of the IPECs and independent from the composition of polycomplexes. Conclusion: According to the obtained results, these IPECs can be considered to have potential in colonic drug delivery as combined pH- and time-dependent systems. © 2009 Informa UK, Ltd

PEGylated systems in pharmaceutics

This review addresses the use of poly(ethylene glycol) (PEG) and PEG conjugation for the design of novel dosage forms and the modification of biomolecules. The peculiarities of PEGylated nanoparticles, liposomes, proteins, enzymes, and small drug and polyelectrolyte molecules and their influence on systemic drug delivery, including overcoming of various biological barriers and adhesion to mucosal tissues (mucoadhesion), are considered

Eudragit E PO as a complementary material for designing oral drug delivery systems with controlled release properties: comparative evaluation of new interpolyelectrolyte complexes with countercharged Eudragit L100 copolymers

The design of new interpolyelectrolyte complexes (IPEC) between countercharged polymers (Eudragit EPO (EPO) and Eudragit L100 (L100)) was investigated. The formation and chemical composition of three new IPECs between EPO and L100 was established by elemental analysis. The structure and solid state properties of the synthesized IPEC were investigated using Fourier transform infrared (FTIR) spectroscopy and modulated temperatre differential scanning calorimetry (MTDSC). The binding ratio of a unit molecule of EPO with L100 was found to range between 1:0.98 (Z = 1.02) and 1:0.50 (Z = 2.00) while increasing the pH from 6.0 to 7.0. As a result of electrostatic interaction between the copolymer chains, the glass transition temperature of the IPEC increased significantly. Considerable pH-sensitive swelling in acidic and neutral media was observed for different type of IPECs. Through evaluation of diffusion-transportation properties of the IPECs, basic mechanisms controlling the delivery of chemically different drugs (diclofenac sodium and theophylline) were obtained. The results of swelling and release of the model drugs from the polycomplex matrices confirm that they have potential to be used in oral controlled drug delivery.status: publishe

Interpolyelectrolyte complexes of Eudragit® E PO with sodium alginate as potential carriers for colonic drug delivery: monitoring of structural transformation and composition changes during swellability and release evaluating

BACKGROUND: With a view to the application in oral colon drug delivery systems, swelling and release behavior of synthesized interpolyelectrolyte complexes (IPEC) between sodium alginate and Eudragit EPO were investigated. METHOD: The microenvironmental changes in IPECs structure as a function of pH during swellability testing were investigated using FT-IR spectroscopy and elementary analysis. RESULTS: All samples of IPECs (Z = 0.66-1.25) during swelling were transformed to a similar structure with approximately the same composition. The release of the model drug diclofenac sodium was significantly delayed from matrices made up of the IPECs and independent from the composition of polycomplexes. CONCLUSION: According to the obtained results, these IPECs can be considered to have potential in colonic drug delivery as combined pH- and time-dependent systems.status: publishe

Drug release modification by interpolymer interaction between countercharged types of Eudragit® RL 30D and FS 30D in double-layer films

Interpolymer interactions between the countercharged methacrylate copolymers Eudragit® RL 30D (polycation) and Eudragit® FS 30D (polyanion), were investigated in conditions mimicking the gastrointestinal environment. The formation of inter-macromolecular ionic bonds between Eudragit® RL 30D and Eudragit® FS 30D was investigated using FT-IR spectroscopy and modulated DSC. The FT-IR spectra of the tested polymeric matrices are characterized by visible changes in the observed IR region indicating the interaction between chains of two oppositely charged copolymers. A new band at 1570 cm-1 appeared which was assigned to the absorption of the carboxylate groups that form the ionic bonds with the quaternary ammonium groups. Moreover, while increasing the pH values from pH 5.8 to 7.4, a decrease of the intensity of the band at 960 cm-1 (quaternary ammonium group vibration) was observed. All binary mixtures were characterized by the presence of only one and narrow Tg, pointing to sample homogeneity, because of the compatibility of components. As a result of electrostatic interaction between the copolymer chains during swelling, the resulting Tg is decreased significantly and was dependent on the quantity of copolymers present in the structure of polycomplexes formed. Overall, the interaction between countercharged copolymers during passage in gastrointestinal tract can strongly modify the release profile of the model drug diclofenac sodium. © 2012 Elsevier B.V. All rights reserved

Interpolyelectrolyte complexes of Eudragit® e PO with sodium alginate as potential carriers for colonic drug delivery: Monitoring of structural transformation and composition changes during swellability and release evaluating

Background: With a view to the application in oral colon drug delivery systems, swelling and release behavior of synthesized interpolyelectrolyte complexes (IPEC) between sodium alginate and Eudragit® EPO were investigated. Method: The microenvironmental changes in IPECs structure as a function of pH during swellability testing were investigated using FT-IR spectroscopy and elementary analysis. Results: All samples of IPECs (Z 0.661.25) during swelling were transformed to a similar structure with approximately the same composition. The release of the model drug diclofenac sodium was significantly delayed from matrices made up of the IPECs and independent from the composition of polycomplexes. Conclusion: According to the obtained results, these IPECs can be considered to have potential in colonic drug delivery as combined pH- and time-dependent systems. © 2009 Informa UK, Ltd

Drug release modification by interpolymer interaction between countercharged types of Eudragit® RL 30D and FS 30D in double-layer films

Interpolymer interactions between the countercharged methacrylate copolymers Eudragit® RL 30D (polycation) and Eudragit® FS 30D (polyanion), were investigated in conditions mimicking the gastrointestinal environment. The formation of inter-macromolecular ionic bonds between Eudragit® RL 30D and Eudragit® FS 30D was investigated using FT-IR spectroscopy and modulated DSC. The FT-IR spectra of the tested polymeric matrices are characterized by visible changes in the observed IR region indicating the interaction between chains of two oppositely charged copolymers. A new band at 1570 cm-1 appeared which was assigned to the absorption of the carboxylate groups that form the ionic bonds with the quaternary ammonium groups. Moreover, while increasing the pH values from pH 5.8 to 7.4, a decrease of the intensity of the band at 960 cm-1 (quaternary ammonium group vibration) was observed. All binary mixtures were characterized by the presence of only one and narrow Tg, pointing to sample homogeneity, because of the compatibility of components. As a result of electrostatic interaction between the copolymer chains during swelling, the resulting Tg is decreased significantly and was dependent on the quantity of copolymers present in the structure of polycomplexes formed. Overall, the interaction between countercharged copolymers during passage in gastrointestinal tract can strongly modify the release profile of the model drug diclofenac sodium. © 2012 Elsevier B.V. All rights reserved