Eudragit E100 surface activity and lipid interactions

In situ and in vitro evaluation of the bioavailability of rumen-protected methionine with coating prototypes

Rumen protected amino acids are supplements that can enhance ruminal performance, yet the coating designed to protect the amino acids might also lead to different effects. Methionine is an essential methyl donor to synthesize protein, and little data exists on the effects of coating materials on its bioavailability. The purpose of this study was to estimate the effect of rumen-protected methionine (RPM) coatings with different ratios of acrylic resin IV (AR), ethyl cellulose (EC), and a mixture of AR and EC (AREC). Fifteen RPMs were prepared according to a single factor design, with 5 proportions each of AR, EC, and AREC to DL-methionine (DL-Met). Twelve hybrid small-tailed Han sheep with rumen fistula were utilized to evaluate in situ escape of RPMs, followed by in vitro abomasum-intestinal release of the RPMs. The results showed a regular variation in both ruminal disappearance and gastrointestinal release of RPMs with different coating prototypes and retention time. The RPMs that were EC and AREC coated presented high bioavailability compared to those with AR. Bioavailability of RPMs was optimal with the 2:20 AREC: DL-Met ratio, when the proportion of AR:EC is 1:1. Additionally, RPMs with a 1:3 ratio of AR:EC confirmed the optimum effect for the RPM of 2:20 AREC: DL-Met. In conclusion, an RPM with a lower AREC ratio coating can achieve better bioavailability and is synergistic to those with EC and AR.

Study of antimycobacterial, cytotoxic, and mutagenic potential of polymeric nanoparticles of copper (II) complex

This study aimed to encapsulate and characterize a potential anti-tuberculosis copper complex (CuCl₂(INH)₂.H₂O:I1) into polymeric nanoparticles (PNs) of polymethacrylate copolymers (Eudragit®, Eu) developed by nanoprecipitation method. NE30D, S100 and, E100 polymers were tested. The physicochemical characterizations were performed by DLS, TEM, FTIR, encapsulation efficiency and, in vitro release studies. Encapsulation of I1 in PN-NE30D, PN-E100, and PN-S100 was 26.3%, 94.5%, 22.6%, respectively. The particle size and zeta potential were 82.3 nm and -24.5 mV for PNs-NE30D, 304.4 nm and +18.7 mV for PNs-E100, and 517.9 nm and -6.9 mV for PNs-S100, respectively. All PDIs were under 0.5. The formulations showed a I1 controlled release at alkaline pH with 29.7% from PNs-NE30D, 7.9% from PNs-E100 and, 28.1% from PNs-S100 at 1 h incubation. PNs were stable for at least 3 months. Particularly, PNs-NE30D demonstrated moderate inhibition of M. tuberculosis and low cytotoxic activity. None of the PNs induced mutagenicity.

Benzoic acid complexes with Eudragit E100®: New alternative antimicrobial preservatives

Given that the use of some preservatives in cosmetics has been restricted, novel alternative preservatives are needed. The aim of this study was to characterize the physicochemical and antimicrobial properties of two polyelectrolyte complexes (EuB₁₀₀ and EuB₇₅Cl₂₅), which were developed through hot melt extrusion (HME) using benzoic acid (BA) and Eudragit E100. Based on phase diagrams and an experimental statistical design, the solubility of the acid in the polymer and the HME conditions were established. Intermolecular interactions were evaluated through Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRPD). Release behavior was determined for the systems. Antibacterial activity and ζ-potential were determined on Escherichia coli. FTIR revealed acid-base interaction, and XPS showed that the percentages of protonated nitrogen N1s were 13.5% for EuB₁₀₀ and 20.3% for EuB₇₅Cl₂₅. The BA released showed a non-Fickian behavior, and a satisfactory antibacterial activity against E. coli was demonstrated at pH 6.9. The complexes modified ζ-potential, destabilizing the membrane functionality of E. coli. These complexes are potential antimicrobial preservatives with a greater spectrum of action, with bactericidal activity against E. coli in a wider pH range than uncomplexed BA, even at pH 6.9.

Solely aqueous formulation of hydrophobic cationic polymers for efficient gene delivery

Cationic polymers are promising gene delivery vectors due to their ability to bind and protect genetic material. The introduction of hydrophobic moieties into cationic polymers can further improve the vector efficiency, but common formulations of hydrophobic polymers involve harsh conditions such as organic solvents, impairing intactness and loading efficiency of the genetic material. In this study, a mild, aqueous formulation method for the encapsulation of high amounts of genetic material is presented. A well-defined pH-responsive hydrophobic copolymer, i.e. poly((n-butylmethacrylate)-co-(methylmethacrylate)-co-(2-(dimethylamino) ethylmethacrylate)), (PBMD) was synthesized by reversible addition fragmentation chain transfer (RAFT) polymerization. Exploiting the pH-dependent solubility behavior of the polymer, stable pDNA loaded nanoparticles were prepared and characterized using analytical ultracentrifugation (AUC), cryo-transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS). This novel formulation approach showed high transfection efficiencies in HEK293T cells, while requiring 5- to 10-fold less pDNA compared to linear polyethylenimine (LPEI), in particular at short incubation times and in serum-containing media. Furthermore, the formulation was successfully adopted for siRNA and mRNA encapsulation and the commercially approved polymer Eudragit® E(PO/100). Overall, the aqueous formulation approach, accompanied by a tailor-made hydrophobic polymer and detailed physicochemical and application studies, led to improved gene delivery vectors with high potential for further applications.

Binary Medical Nanofluids by Combination of Polymeric Eudragit Nanoparticles for Vehiculization of Tobramycin and Resveratrol: Antimicrobial, Hemotoxicity and Protein Corona Studies

The development of smart nanoparticles (NPs) became a trend to enhance the delivery of drugs. In the present work, Tobramycin (TB), an aminoglycoside antibiotic that displays several undesirable side effects, has been encapsulated into cationic Eudragit®E100 (E100) NPs for the treatment of infections caused by Pseudomonas aeruginosa. Combination with neutral Eudragit®NE30D (NE30D) NPs containing resveratrol (RSV), a strong natural antioxidant, increased the antimicrobial activity of TB (75% higher than free TB). NPs were stabilized with 1.0% (w/v) poloxamer 188 (P188) or poloxamer 407 (P407) as surfactants. E100 NPs showed 83.3 ± 8.5%, and 70.1 ± 2.7 encapsulation efficiency (EE) of TB with P188 and P407 coatings, respectively. The presence of NPs was confirmed by DLS and TEM studies. TB was controlled released from NPs for 6 h. Hemotoxicity tests of NPs in the range of MIC values on human blood gave negative results. Analysis of Surface Plasmon Resonance verified that NE30D/P407/RSV does not interact with plasma proteins BSA, IgG or fibrinogen, besides E100/P188/TB interact with BSA, findings that are compatible with a negligible in vivo clearance of the nanovehicles. The obtained results show a potential binary fluid composed of two NPs to highly improve the effectiveness of conventional antibiotics.

Lamotrigine Nanoparticle Laden Polymer Composite Oral Dissolving Films for Improving Therapeutic Potential of the Hydrophobic Antiepileptic Molecule

Lamotrigine is used for neurological disorders and antiepileptic therapy at frequent dosing due to its poor solubility. The present work aims to study the influence of combining the Lamotrigine nanoparticles and polymer composite oral dissolving film to improve the solubility and dissolution kinetics of the drug. The Lamotrigine-Eudragit E100 nanoparticles were synthesized through solvent evaporation followed by precipitation process, which were laden in oral dissolving films through solvent casting technique. The optimized nanoparticles were assessed for particle size, colloidal stability, drug entrapment efficiency, in vitro release profile, physicochemical characteristics, and cytotoxicity. The optimized polymeric nanoparticles of Lamotrigine: Eudragit E100 (1:0.5) exhibited monodispersed particles with 103 nm average size, +7.96 mV zeta potential, and 82.96% ± 1.2% entrapment efficiency. The composite oral matrix films blended with polyvinyl alcohol and polyvinyl pyrrolidone (0.5:0.5 ratio) incorporated with the polymeric nanoparticles demonstrated >64% drug release within 2 h. The nanoparticles and its composite films exhibited 9- and 11-fold higher drug release than pure drug, respectively. The analytical characterization studies proved the formation of nanoparticles with mild drug-polymer interactions and optimum stability, which resulted in enhanced solubility and dissolution of drug. The nanoparticles displayed lesser cytotoxicity to the normal (Vero) cells at concentration of 10-50 μg/mL compared to pure drug. The optimized polymeric nanoparticle loaded oral films could be suitable for in vivo administration of Lamotrigine at low doses to improve bioavailability and therapeutic efficiency with reduced side effects.

pH Tunable Thin Film Gradients of Magnetic Polymer Colloids for MRI Diagnostics

Magnetic polymer colloids comprising of magnetite (Fe₃O₄) nanoparticles and Eudragit E100 were employed to fabricate thin film gradients and were investigated for in-vitro magnetic resonance imaging. Magnetic polymer colloids (MPC) and polyacrylic acid (PAA) with stimuli-responsive cationic and anionic functional groups respectively facilitate the formation of thin film gradients via layer by layer technique. The characteristics of films were controlled by changing the pH and level of the adsorbing solutions that lead to the development of gradient films having 5.5, 10.5 and 15.5 bilayers. Optical microscopy, scanning electron microscopy and magnetic force microscopy was carried out to determine the surface coverage of films. Surface wettability demonstrated the hydrophilicity of adsorbed colloids. The developed thin-film gradients were explored for in vitro magnetic resonance imaging that offers a point of care lab-on-chip as a dip-stick approach for ultrasensitive in-vitro molecular diagnosis of biological fluids.

Poly-L-lactide scaffolds with super pores obtained by freeze-extraction method

A nonplanar polylactide scaffold to be used in tissue engineering was obtained by freeze-extraction method. Properties of the scaffold were modified by adding Eudragit® E100. The impact of the modification on morphology, porosity and pore size, mass absorbability, mechanical properties was determined. Scanning electron microscopy (SEM), hydrostatic weighing test, static compression test was used to this end. The chemical composition of the scaffold was defined based on infrared spectroscopy (FTIR) and energy-dispersive X-ray spectroscopy (EDX). Biocompatibility was confirmed by quantitative tests and microscopic observation. The obtained results show that the obtained scaffolds may be applied as a carrier of hydrophilic cellular growth factors for more efficient tissue regeneration.

Development of Polyelectrolyte Complex Nanoparticles-PECNs Loaded with Ampicillin by Means of Polyelectrolyte Complexation and Ultra-High Pressure Homogenization (UHPH)

This study was focused on synthesizing, characterizing and evaluating the biological potential of Polyelectrolyte Complex Nanoparticles (PECNs) loaded with the antibiotic ampicillin. For this, the PECNs were produced initially by polyelectrolytic complexation (bottom-up method) and subsequently subjected to ultra-high pressure homogenization-UHPH (top-down method). The synthetic polymeric materials corresponding to the sodium salt of poly(maleic acid-alt-octadecene) (PAM-18Na) and the chloride salt of Eudragit E-100 (EuCl) were used, where the order of polyelectrolyte complexation, the polyelectrolyte ratio and the UHPH conditions on the PECNs features were evaluated. Likewise, PECNs were physicochemically characterized through particle size, polydispersity index, zeta potential, pH and encapsulation efficiency, whereas the antimicrobial effect was evaluated by means of the broth microdilution method employing ampicillin sensitive and resistant S. aureus strains. The results showed that the classical method of polyelectrolyte complexation (bottom-up) led to obtain polymeric complexes with large particle size and high polydispersity, where the 1:1 ratio between the titrant and receptor polyelectrolyte was the most critical condition. In contrast, the UHPH technique (top-down method) proved high performance to produce uniform polymeric complexes on the nanometric scale (particle size < 200 nm and PDI < 0.3). Finally, it was found there was a moderate increase in antimicrobial activity when ampicillin was loaded into the PECNs.

Intermolecular Interactions between Drugs and Aminoalkyl Methacrylate Copolymer in Solution to Enhance the Concentration of Poorly Water-Soluble Drugs

An aminoalkyl methacrylate copolymer, Eudragit^® E (EUD-E), has gained tremendous attention as a solid dispersion carrier because it efficiently stabilizes drugs in the amorphous state. Furthermore, EUD-E remarkably enhances drug dissolution in water. This review focuses on the interaction between drugs and EUD-E in solution, which contributes to the enhancement of drug concentration. Studies examining interactions between acidic drugs and EUD-E in organic solvents have revealed that the interaction occurs predominantly by electrostatic interaction, including hydrogen bonding and dipolar interactions. Other studies on interactions in aqueous solution found evidence for strong electrostatic interactions between acidic drugs and EUD-E in ion exchange experiments. ¹H-NMR studies using high-resolution magic-angle spinning, nuclear Overhauser effect spectroscopy, diffusion, and relaxation time measurements successfully identified the interaction site and strength in aqueous solution. Hydrophobic and ionic interactions occurred between drugs and EUD-E. The conformation of EUD-E, which was affected by the ionic strength and pH of the aqueous media, also influenced the interaction. The knowledge discussed in this review will be helpful in designing solid dispersion formulations with EUD-E, which will efficiently enhance drug concentration and subsequent absorption into the body.

Relationship between Degree of Polymeric Ionisation and Hydrolytic Degradation of Eudragit® E Polymers under Extreme Acid Conditions

The commercial copolymers Eudragit^® E 100 and Eudragit^® PO are widely used materials in the pharmaceutical field as coating systems. Such materials derived from amino-methacrylate groups under acidulated conditions may acquire an ionisable fraction or undergo hydrolytic degradation of the polymeric structure. This work focused on establishing the chemical, physical, and surface changes of two reprocessed polymeric materials, here named as EuCl-E-100 and EuCl-E-PO, which were obtained from the commercial Eudragit^® E 100 and Eudragit^® E PO, respectively. The commercial materials were exposed to extreme acid conditions, where the polymers were solubilised and subsequently dried by the refractance window method. The materials obtained were chemically characterised by potentiometric titration, nuclear magnetic resonance spectroscopy (¹H NMR and ¹³C NMR) in one and two dimensions (COSY, HSQC, and HMBC), infrared spectroscopy, X-ray diffraction, and differential scanning calorimetry. Changes in the physical properties of the materials were evaluated through studies of flowability, compactability, and their ability to gain and lose humidity. Surface thermodynamic studies were carried out through contact angle measurements using the sessile drop method. The results showed that the processed polymeric materials acquired a substantial degree of ionisation without undergoing hydrolysis of the esterified groups. Furthermore, such changes improved the flow characteristics of the material and the solubility in aqueous media at pH > 5, while also maintaining the hydrophobicity degree of the polymeric surface.

Potential of Chemical and Physical Enhancers for Transungual Delivery of Amorolfine Hydrochloride

Topical monotherapy of nail infection is limited by poor drug permeability into the human nail plate. Numerous substances and methods are applied to improve the antifungal agent delivery across the nail plate. This work aimed to evaluate the effect of chemical and physical enhancers on the accumulation and permeation of amorolfine hydrochloride through human nail clippings. Polymeric nail lacquers with Eudragit E100 were developed as a potentially suitable delivery system for amorolfine hydrochloride. Incorporating thioglycolic acid and urea into formulations provided increased accumulation of antifungal agent in nail layers of up to 100% and 57%, respectively. Structural changes of nail barrier, induced by fractional CO₂ laser, were visualized by microscopy. The permeation of amorolfine hydrochloride through the nail increased twofold when thioglycolic acid-containing formulation was applied and the nail was pretreated with a fractional CO₂ laser. The results suggest that this novel combination of enhancers has the potential to be an effective option for topical drug delivery through the nail, and increased the efficacy of treatment.

Enhanced In Situ Availability of Aphanizomenon Flos-Aquae Constituents Entrapped in Buccal Films for the Treatment of Oxidative Stress-Related Oral Diseases: Biomechanical Characterization and In Vitro/Ex Vivo Evaluation

In recent years, the key role of oxidative stress in pathogenesis of oral diseases has been emphasized and the use of antioxidant agents has been encouraged. Aphanizomenon flos-aquae (AFA) is a unicellular blue-green alga with antioxidant and anti-inflammatory properties. The aim of this study was the formulation and characterization of mucoadhesive thin layer films loaded with AFA, finalized to the treatment of oxidative stress (OS)-related oral diseases. First, to enhance the bioavailability of AFA constituents, the raw food grade material was appropriately treated by a high frequency homogenization able to disrupt cell walls. Thus, Eudragit^® E100-based buccal films were produced by the solvent casting method, containing 7% and 18% of AFA. The films, characterized by uniformity in thickness, weight, and drug content, showed low swelling degree, good muco-adhesiveness and controlled drug release. The mechanical tests showed elastic moduli of films of almost 5 MPa that is well-suitable for human buccal applications without discomfort, besides biaxial tests highlighted a marked material isotropy. Permeation studies through porcine mucosae demonstrated the ability of films to promote AFA penetration in the tissues, and when sublingually administered, they produced a drug flux up to six-fold higher than an AFA solution. The new formulations represent an interesting alternative for the development of cosmetics and nutraceuticals with a functional appeal containing plant extracts.

Decrease of Antimicrobial Resistance through Polyelectrolyte-Coated Nanoliposomes Loaded with β-Lactam Drug

Currently, one of the greatest health challenges worldwide is the resistance to antibiotic drugs, which has led to the pursuit of new alternatives for the recovery of biological activity, where the use of different types of nano-systems has shown an interesting potential. In this study, we evaluated the antibiotic activity of a model drug (ampicillin) encapsulated within coated-nanoliposomes on strains of Staphylococcus aureus with different antibiotic-resistance degrees. Hence, liposomes were elaborated by the ethanol injection method and were coated with a cationic polymer (Eudragit E-100) through the layer-by-layer process. Liposome characterization, such as size, polydispersity, zeta potential, and encapsulation efficiency were determined using dynamic light scattering and ultrafiltration/centrifugation techniques. Although biological activity was evaluated using three ATCC strains of S. aureus corresponding to ATCC 25923 (sensitive), ATCC 29213 (resistant) and ATCC 43300 (very resistant). The results showed changes in size (from ~150 to 220 nm), polydispersity (from 0.20 to 0.45) and zeta potential (from -37 to +45 mV) for the coating process. In contrast, encapsulation efficiency of approximately 70% and an increase in antibiotic activity of 4 and 18 times more on those S. aureus-resistant strains have been observed.

Physicochemical characterization of in situ drug-polymer nanocomplex formed between zwitterionic drug and ionomeric material in aqueous solution

Biocompatible polymeric materials with the potential to form functional structures, in association with different therapeutic molecules, in physiological media, represent a great potential for biological and pharmaceutical applications. Therefore, here the formation of a nano-complex between a synthetic cationic polymer and model drug (ampicillin trihydrate) was studied. The formed complex was characterized by size and zeta potential measurements, using dynamic light scattering and capillary electrophoresis. Moreover, the chemical and thermodynamically stability of these complexes were studied. The ionomeric material, here referred as EuCl, was obtained by equimolar reaction between Eudragit E and HCl. The structural characterization was carried out by potentiometric titration, FTIR spectroscopy, and DSC. The effect of pH, time, polymer concentration and ampicillin/polymer molar ratio over the hydrodynamic diameter and zeta potential were established. The results show that EuCl ionomer in aqueous media presents two different populations of nanoparticles; one of this tends to form flocculated aggregates in high pH and concentrations, by acquiring different conformations in solution by changing from a compact to an extended conformation. Moreover, the formation of an in situ interfacial polymer-drug complex was demonstrated, this could slightly reduce the hydrolytic degradation of the drug while affecting its solubility, mainly under acidic conditions.

Dimethylaminoethyl methacrylate copolymer-siRNA nanoparticles for silencing a therapeutically relevant gene in macrophages

DMC nanoparticles target Bfl1/A1 gene in lung macrophages and effective silencing of Bfl1/A1 gene by DMC nanoparticles paves the way for research on alternative treatment strategies for tuberculosis.

Ocular delivery of flurbiprofen based on Eudragit(®) E-flurbiprofen complex dispersed in aqueous solution: preparation, characterization, in vitro corneal penetration, and ocular irritation

A novel ophthalmic formulation based on the ionic complexation between Eudragit E 100 (EU) and flurbiprofen (FB) is proposed. The selected complex composition, named EU-FBH50 Cl50 , had the basic groups of EU completely neutralized with equal molar amounts of FB and HCl. This complex, obtained in the solid state, exhibited a high aqueous compatibility producing a colloidal dispersion with a high positive electrokinetic potential, in which more than 99% of FB was ionically condensed with EU. In bicompartimental Franz cells, FB diffusion from the complex was very slow. However, dispersion in 0.9% NaCl increased the FB release through an ionic exchange, providing an optimal constant rate of delivery. Corneal FB permeation from 0.1% EU-FBH50 -Cl50 dispersed in 0.9% NaCl solution was substantially more effective compared with 0.1% FB solution, EU-FBH50 -Cl50 (Dex), or Tolerane(®) (a marketed formulation). This complex formulation was shown to be innocuous for rabbit ocular tissues because no irritant effects were evidenced.

Effect of aminoalkyl methacrylate copolymer E/HCl on in vivo absorption of poorly water-soluble drug

This study aimed to investigate in vivo absorption of tacrolimus formulated as a solid dispersion using Eudragit E®/HCl (E-SD). E-SD is an aminoalkyl methacrylate copolymer that can be dissolved under neutral pH conditions. E-SD was used alone as a solid dispersion carrier and/or was mixed with tacrolimus primarily dispersed with hydroxypropylmethylcellulose (HPMC). Tacrolimus was formulated with E-SD at several different ratios. Formulations with tacrolimus/E-SD ratio of 1/3 showed higher in vivo absorption, compared to tacrolimus dispersed in the excipients (primarily HPMC) found in commercially available tacrolimus capsules, using a rat in situ closed loop method. Good correlation was observed between in vitro drug solubility and in vivo drug absorption. In vitro solubility tests and rat oral absorption studies of tacrolimus/HPMC solid dispersion formulations were also conducted after mixing the HPMC dispersion with several ratios of E-SD. E-SD/tacrolimus/HPMC formulations yielded high in vitro drug solubility but comparatively low in vivo absorption. Dog oral absorption studies were conducted using capsules containing a formulation of tacrolimus/E-SD at a ratio of 1/5. The E-SD formulation-containing capsule showed higher in vivo drug absorption than tacrolimus dispersed in the standard HPMC capsule. These studies report enhancement of the in vivo absorption of a poorly water-soluble drug following dispersion with E-SD when compared to formulation in HPMC.