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James W Mcginity - One of the best experts on this subject based on the ideXlab platform.

  • Properties of theophylline tablets dry powder coated with Eudragit E PO and Eudragit L 100-55.
    Pharmaceutical development and technology, 2009
    Co-Authors: Dorothea Sauer, James W Mcginity
    Abstract:

    The aim of the present study was to investigate the influence of Eudragit E PO on the drug release mechanism of Eudragit L 100-55 film coatings applied to theophylline tablets by a dry powder coating technique. The process was entirely liquid-free. Calculation of the Flory-Huggins interaction parameter based on solubility parameters suggested immiscibility of the two copolymers. MDSC thermograms were characterized by two glass transitions for the investigated Eudragit E PO/Eudragit L 100-55 ratios and confirmed incomplete miscibility of the copolymers at processing conditions. FT-IR analysis was employed to study binding interactions of the polymers. Due to the higher affinity of the plasticizer, triethyl citrate, for Eudragit E PO compared to Eudragit L 100-55, redistribution of the plasticizer was observed during the curing phase of the process. Plasticizer migration also affected the initial phase of drug release from powder-coated theophylline tablets that were stored for four weeks. Drug release from powder-coated tablets was dependent on the polymer blend ratio, coating thickness, and the pH of the dissolution medium. A broad range of pH dependent theophylline release profiles were obtained as a function of the polymer blend ratio. The particle size of the coating powder influenced the microstructure of the film coating.

  • influence of methylparaben as a solid state plasticizer on the physicochemical properties of Eudragit rs po hot melt extrudates
    European Journal of Pharmaceutics and Biopharmaceutics, 2003
    Co-Authors: James W Mcginity
    Abstract:

    The purpose of this study was to investigate the properties of methylparaben as a solid-state plasticizer for Eudragit® RS PO during a hot-melt extrusion process. Extruded matrices containing different levels of methylparaben and Eudragit® RS PO, were prepared by feeding the powder blend through a hot melt extruder. The melt viscosity of the polymer blends was assessed by torque rheometry using a Brabender Plasticorder. The physicochemical properties of the extruded methylparaben-containing polymer matrix were characterized by differential scanning calorimetry and X-ray diffraction. Solid state nuclear magnetic resonance spectroscopy (NMR) was used to study the possible interaction between methylparaben and Eudragit® RS PO polymer. The results demonstrated that the glass transition temperature of the Eudragit® RS PO decreased with increasing levels of methylparaben in the extrudate, due to an increase in the chain mobility of Eudragit® RS PO. The crystallinity of methylparaben was absent following hot-melt processing. At increasing levels of methylparaben in the extrudates, a decrease in the melt viscosity was seen due to a plasticization of the polymer. Rheological properties of the extrudates containing methylparaben were compared with the extrudates containing conventional plasticizers. It was found that methylparaben was as effective as triethyl citrate (TEC) in reducing torque during the extrusion process. Solid state NMR spectra indicated a change in the chemical shift of Eudragit® RS PO plasticized with methylparaben, which could be ascribed to an interaction between the hydroxyl group of the methylparaben and the ester group of the Eudragit® RS PO polymer. The results of this study demonstrated that methylparaben could be used as a solid-state plasticizer for the Eudragit® RS PO polymer when a hot melt extrusion technique was employed in the preparation of sustained release tablets.

  • influence of Eudragit ne 30 d blended with Eudragit l 30 d 55 on the release of phenylpropanolamine hydrochloride from coated pellets
    Drug Development and Industrial Pharmacy, 2003
    Co-Authors: Weijia Zheng, James W Mcginity
    Abstract:

    AbstractThe objective of this study was to investigate the influence of Eudragit® NE 30 D blended with Eudragit® L 30 D-55 on the release of phenylpropanolamine hydrochloride (PPA·HCl) from coated pellets. The miscibility of Eudragit NE 30 D/L 30 D-55 blends at different ratios was studied by using differential scanning calorimetry. The release of PPA·HCl from pellets coated with Eudragit NE 30 D alone and a Eudragit NE 30 D/L 30 D-55 blend, when stored at 40°C and 60°C, was determined by UV spectroscopy. Eudragit NE 30 D and Eudragit L 30 D-55 were miscible in ratios greater than 4:1. The curing time that was required to reach an equilibrium state decreased with the addition of Eudragit L 30 D-55. The presence of Eudragit L 30 D-55 also produced a film coating that was less tacky, and a dispersion of Eudragit NE 30 D containing Eudragit L 30 D-55 (5:1) was shown to prevent agglomeration of the pellets during coating and storage.

  • Influence of an Enteric Polymer on Drug Release Rates of Theophylline from Pellets Coated with Eudragit® RS 30D
    Pharmaceutical development and technology, 2003
    Co-Authors: James W Mcginity
    Abstract:

    The purpose of this research study was to investigate the influence of an enteric polymer on the drug release properties of theophylline pellets coated with Eudragit® RS 30D. Theophylline pellets were coated with aqueous colloidal dispersions of Eudragit® RS 30D containing various amounts of Eudragit® L 100-55. The effect of storage conditions on the release of drug from coated pellets was determined as a function of the pH of the dissolution medium. The results from the dissolution study showed significant changes in the dissolution rate of theophylline from pellets coated with Eudragit® RS 30D when cured at 40°C for 4 days. No change in the drug release rate was observed when Eudragit® L100-55 was present in the Eudragit® RS 30D dispersion. Increasing the ratio of Eudragit® L100-55 to Eudragit® RS 30D resulted in faster drug release rates from the coated pellets. An increase in the pH of the dissolution medium was found to enhance drug release from the pellets coated with Eudragit® RS 30D containing Eud...

N. Kurjakovic - One of the best experts on this subject based on the ideXlab platform.

  • A pH-Dependent Colon-Targeted Oral Drug Delivery System Using Methacrylic Acid Copolymers. II. Manipulation of Drug Release Using Eudragit® L100 and Eudragit S100 Combinations
    Drug development and industrial pharmacy, 2000
    Co-Authors: M. Z. I. Khan, H. P. Stedul, N. Kurjakovic
    Abstract:

    Tablets containing mesalazine as a model drug were coated using various combinations of two methacrylic acid copolymers, (Eudragit® L100 and Eudragit S100) by spraying from aqueous systems. The Eudragit L100–Eudragit S100 (w/w) combinations studied were 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, 1:5, and 0:1. The coated tablets were tested in vitro for their suitability for pH-dependent colon-targeted oral drug delivery. The dissolution profiles of the drug obtained from the studied tablets demonstrate that the release of the drug could be manipulated by changing the Eudragit L100–Eudragit S100 ratios in the combinations within the pH range between 6.0 and 7.0 in which the individual polymers are soluble, and a coating formulation consisting of a combination of the two polymers can overcome the issue of high gastrointestinal (GI) pH variability among individuals. The results also demonstrate the feasibility of using aqueous dispersions of Eudragit L100–Eudragit S100 combinations for coating tablets for colon-targeted ...

  • a ph dependent colon targeted oral drug delivery system using methacrylic acid copolymers i manipulation of drug release using Eudragit l100 55 and Eudragit s100 combinations
    Journal of Controlled Release, 1999
    Co-Authors: Zahirul M I Khan, željko Prebeg, N. Kurjakovic
    Abstract:

    Abstract Lactose-based placebo tablets were coated using various combinations of two methacrylic acid copolymers, Eudragit® L100-55 and Eudragit® S100, by spraying from aqueous systems. The Eudragit® L100-55–Eudragit® S100 combinations (w/w) studied were 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, 1:5 and 0:1. The coated tablets were tested in vitro for their suitability for pH dependent colon targeted oral drug delivery. The same coating formulations were then applied on tablets containing mesalazine as a model drug and evaluated for in vitro dissolution rates under various conditions. The disintegration data obtained from the placebo tablets demonstrate that disintegration rate of the studied tablets is dependent on: (i) the polymers combination used to coat the tablets, (ii) pH of the disintegration media, and (iii) the coating level of the tablets. Dissolution studies performed on the mesalazine tablets further confirmed that the release profiles of the drug could be manipulated by changing the Eudragit® L100-55 and Eudragit® S100 ratios within the pH range of 5.5 to 7.0 in which the individual polymers are soluble respectively, and a coating formulation consisting of a combination of the two copolymers can overcome the issue of high gastrointestinal (GI) pH variability among individuals. The results also demonstrated that a combination of Eudragit® L100-55 and Eudragit® S100 can be successfully used from aqueous system to coat tablets for colon targeted delivery of drugs and the formulation can be adjusted to deliver drug at any other desirable site of the intestinal region of the GI tract on the basis of pH variability. For colon targeted delivery of drugs the proposed combination system is superior to tablets coated with either Eudragit® L100-55 or Eudragit® S100 alone.

Philippe Maincent - One of the best experts on this subject based on the ideXlab platform.

  • impact of bulk and surface properties of some biocompatible hydrophobic polymers on the stability of methylene chloride in water mini emulsions used to prepare nanoparticles by emulsification solvent evaporation
    Colloids and Surfaces B: Biointerfaces, 2007
    Co-Authors: Valery G Babak, Francis Baros, Omar Boulanouar, Frank Boury, M Fromm, Nathalie R Kildeeva, Nathalie Ubrich, Philippe Maincent
    Abstract:

    The emulsifying and stabilizing ability of several hydrophobic (insoluble in water and soluble in volatile organic solvents) polymers, such as Eudragit RL, Eudragit RS, PLGA, PCL, and their mixtures, with regard to the methylene chloride (MC)-in-water mini-emulsions, has been compared to the viscosity of MC solutions and to the properties of adsorption and spread monolayers of these polymers. Eudragits RS and RL contain ∼2.5 and ∼5 mol% of pendent cationic trimethylammonium (TMA) groups per ∼164 g/mol segments, whereas PLGA and PCL contain 1 and 2 polar carbonyl groups per 130 and 114 g/mol, respectively. The electrostatic attraction between the dipoles, formed by TMA groups and the condensed counter ions in the MC solutions, leads to the contraction of macromolecular coils of Eudragits, whereas the PLGA and PCL macromolecules, interacting by low polar carbonyl groups (with dipole moment μ = 2.7 D) retain more extended conformation in MC. This explains why the characteristic viscosities [η] of MC solutions are much lower for the former polymers (∼0.1 dL/g) with regard to PLGA and PCL solutions whose [η] is equal to 0.3 and 0.6 dL/g, respectively. The ionization of TMA groups in contact with the water phase leads to the irreversible adsorption of Eudragits at the MC/water interface and to high decrease of the interfacial tension γ (down to 4 mN/m for the 5% MC solutions). Whereas PLGA and PCL possessing low polar carbonyl groups adsorb poorly at the MC/water interface exhibiting γ ≅ 28 mN/m. Higher stability of spread monolayers of Eudragits (π* ∼ 40 mN/m) with regard to PLGA and PCL (π* < 20 mN/m) correlates well with higher interfacial activity of the former with regard to the later. The higher surface potential ΔV of Eudragits (0.9 V) with regard to PLGA (0.3 V) and PCL (0.4 V) is explained by the formation of electric double layer (DL) by the former, whereas the later contribute to the ΔV only by cumulative dipole moments of carbonyl groups. The experimental values of surface potentials correlate well with the Gouy–Chapman model of the DL and the Helmholtz model of the monolayer. The ensemble of experimental results leads to the conclusion that higher emulsifying and stabilizing ability of Eudragits with regard to PLGA and PCL is due to higher adsorption activity of the former which form the corona of polymeric chains with ionized TMA groups around the droplets. It can be postulated that Eudragit polymers have good surface active properties which may allow manufacturing of biocompatible nanoparticles by emulsification–solvent evaporation method without surfactants.

  • Impact of bulk and surface properties of some biocompatible hydrophobic polymers on the stability of methylene chloride-in-water mini-emulsions used to prepare nanoparticles by emulsification-solvent evaporation.
    Colloids and Surfaces B: Biointerfaces, 2007
    Co-Authors: Valery G Babak, Francis Baros, Omar Boulanouar, Frank Boury, M Fromm, Nathalie R Kildeeva, Nathalie Ubrich, Philippe Maincent
    Abstract:

    The emulsifying and stabilizing ability of several hydrophobic (insoluble in water and soluble in volatile organic solvents) polymers, such as Eudragit RL, Eudragit RS, PLGA, PCL, and their mixtures, with regard to the methylene chloride (MC)-in-water mini-emulsions, has been compared to the viscosity of MC solutions and to the properties of adsorption and spread monolayers of these polymers. Eudragits RS and RL contain approximately 2.5 and approximately 5 mol% of pendent cationic trimethylammonium (TMA) groups per approximately 164 g/mol segments, whereas PLGA and PCL contain 1 and 2 polar carbonyl groups per 130 and 114 g/mol, respectively. The electrostatic attraction between the dipoles, formed by TMA groups and the condensed counter ions in the MC solutions, leads to the contraction of macromolecular coils of Eudragits, whereas the PLGA and PCL macromolecules, interacting by low polar carbonyl groups (with dipole moment mu = 2.7 D) retain more extended conformation in MC. This explains why the characteristic viscosities [eta] of MC solutions are much lower for the former polymers ( approximately 0.1 dL/g) with regard to PLGA and PCL solutions whose [eta] is equal to 0.3 and 0.6 dL/g, respectively. The ionization of TMA groups in contact with the water phase leads to the irreversible adsorption of Eudragits at the MC/water interface and to high decrease of the interfacial tension gamma (down to 4 mN/m for the 5% MC solutions). Whereas PLGA and PCL possessing low polar carbonyl groups adsorb poorly at the MC/water interface exhibiting gamma congruent with 28 mN/m. Higher stability of spread monolayers of Eudragits (pi* approximately 40 mN/m) with regard to PLGA and PCL (pi* < 20 mN/m) correlates well with higher interfacial activity of the former with regard to the later. The higher surface potential DeltaV of Eudragits (0.9 V) with regard to PLGA (0.3 V) and PCL (0.4V) is explained by the formation of electric double layer (DL) by the former, whereas the later contribute to the DeltaV only by cumulative dipole moments of carbonyl groups. The experimental values of surface potentials correlate well with the Gouy-Chapman model of the DL and the Helmholtz model of the monolayer. The ensemble of experimental results leads to the conclusion that higher emulsifying and stabilizing ability of Eudragits with regard to PLGA and PCL is due to higher adsorption activity of the former which form the corona of polymeric chains with ionized TMA groups around the droplets. It can be postulated that Eudragit polymers have good surface active properties which may allow manufacturing of biocompatible nanoparticles by emulsification-solvent evaporation method without surfactants.

Ganeshchandra S Sonavane - One of the best experts on this subject based on the ideXlab platform.

  • preparation and in vitro in vivo evaluation of gliclazide loaded Eudragit nanoparticles as a sustained release carriers
    Drug Development and Industrial Pharmacy, 2007
    Co-Authors: Padma V Devarajan, Ganeshchandra S Sonavane
    Abstract:

    ABSTRACTThe aim of this study was to formulate and optimize gliclazide-loaded Eudragit nanoparticles (Eudragit L100 and Eudragit RS) as a sustained release carrier with enhanced efficacy. Eudragit L 100 nanoparticles (ELNP) were prepared by controlled precipitation method whereas Eudragit RSPO nanoparticles (ERSNP) were prepared by solvent evaporation method. The influence of various formulation factors (stirring speed, drug:polymer ratio, homogenization, and addition of surfactants) on particle size, drug loading, and encapsulation efficiency were investigated. The developed Eudragit nanoparticles (L100 and RS) showed high drug loading and encapsulation efficiencies with nanosize. Mean particle size altered by changing the drug:polymer ratio and stirring speed. Addition of surfactants showed a promise to increase drug loading, encapsulation efficiency, and decreased particle size of ELNP as well as ERSNP. Dissolution study revealed sustained release of gliclazide from Eudragit L100 as well as Eudragit RS...

  • Preparation and in vitro/in vivo evaluation of gliclazide loaded Eudragit nanoparticles as a sustained release carriers.
    Drug development and industrial pharmacy, 2007
    Co-Authors: Padma V Devarajan, Ganeshchandra S Sonavane
    Abstract:

    ABSTRACTThe aim of this study was to formulate and optimize gliclazide-loaded Eudragit nanoparticles (Eudragit L100 and Eudragit RS) as a sustained release carrier with enhanced efficacy. Eudragit L 100 nanoparticles (ELNP) were prepared by controlled precipitation method whereas Eudragit RSPO nanoparticles (ERSNP) were prepared by solvent evaporation method. The influence of various formulation factors (stirring speed, drug:polymer ratio, homogenization, and addition of surfactants) on particle size, drug loading, and encapsulation efficiency were investigated. The developed Eudragit nanoparticles (L100 and RS) showed high drug loading and encapsulation efficiencies with nanosize. Mean particle size altered by changing the drug:polymer ratio and stirring speed. Addition of surfactants showed a promise to increase drug loading, encapsulation efficiency, and decreased particle size of ELNP as well as ERSNP. Dissolution study revealed sustained release of gliclazide from Eudragit L100 as well as Eudragit RS...

Rawia M. Khalil - One of the best experts on this subject based on the ideXlab platform.

  • Preparation and Evaluation of Sustained-Release Solid Dispersions of Drugs with Eudragit Polymers
    Drug Development and Industrial Pharmacy, 1997
    Co-Authors: Hussein O. Ammar, Rawia M. Khalil
    Abstract:

    AbstractCoevaporates of paracetamol and rifampicin with Eudragit polymers of different natures (anionic, cationic, and zwitterionic) were prepared. Determination of dissolution rate of these coevaporates in dissolution media simulating those of the gastrointestinal tract (GIT) revealed that the release rate of paracetamol is retarded from all the coevaporates studied. In this respect, Eudragit L100-SS shows the highest sustainment of drug release, while Eudragit E100 shows the lowest. Conversely, the release of rifampicin from its coevaporates with the anionic Eudragit S100 polymer is more retarded than the corresponding coevaporate with the zwitterionic Eudragit RL100 or from coevaporates with equal mixtures of the two polymers.Increasing the polymer weight fraction in rifampicin coevaporates with Eudragit S100 up to 0.5 resulted in a corresponding decrease in the dissolution rate. However, beyond this weight fraction, the polymer effect on the dissolution rate of the drug becomes minimized. The results ...