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.

Characteristics of interpolyelectrolyte complexes of Eudragit E 100 with sodium alginate.

With a view to the application in oral drug delivery formulations, the possibility to form interpolyelectrolyte complexes (IPEC) of Eudragit E 100 (EE) with sodium alginate (AL) was investigated, employing turbidimetry, apparent viscosity measurements, FT-IR and elementary analysis. The interaction or binding ratio of a unit molecule of AL with EE was largely affected by the pH value of the media, showing a change from 1.5:1 to 1:1.25 (0.66

Characteristics of interpolyelectrolyte complexes of Eudragit E100 with Eudragit L100.

With a view to the application in oral controlled drug delivery systems, the formation of interpolyelectrolyte complexes (IPEC) between Eudragit E100 (EE) and Eudragit L100 (EL) was investigated, using turbidimetry, solution viscosity measurements and elementary analysis. The structure of the synthesized IPEC was investigated by using FT-IR spectroscopy. The binding ratio of a unit molecule of EL with EE was found to be approximately 1:1 in pH 6.0. Based on the results of elementary analysis, and FT-IR, the binding ratio of each component in the solid complexes was very close to that observed in turbidity and viscosity measurements and indicate that the synthesized products can be considered as IPEC. Due to the structure of the IPEC, two maxima were observed in the swelling behaviour as a function of pH. The release of the model drug ibuprofen was significantly retarded from tablets made up of the IPEC.

[The pharmacokinetics of the new Russian prolonged-action form of diclofenac sodium--Ortopek--in a single oral dose]. / Farmakokinektika novoi otechestvennoi prolongirovannoi formy diklofenaka natriia--ortopéka--pri odnorazovom prieme vnutr'.

Ortopak tablets, 100 mg, were investigated. The pharmacokinetics of Ortopak was studied in 10 rheumatoid arthritis patients after a single oral dose of 100 mg. Ortophenum and voltaren-retard (Ciba-Geigy) were used for comparison. Diclophenac-sodium was measured in the patient's plasma by using high performance liquid chromatography. Ortopak was shown to be eliminated from the patient's body much slower than Ortophenum. The bioequivalence of Ortopak versus Ortophenum was 62.7%. The pharmacokinetic properties of Ortopak were similar to those of Voltaren-retard, which were close to those of diclophenac-sodium in the blood plasma within the therapeutic range.