Influence of selected surfactants on the tackiness of acrylic polymer films

Anti-tacking agents are always necessary in polymeric film coating formulations in order to prevent substrate agglomeration. The objective of this study was to investigate the abilities of certain nonionic surfactants in a group of sorbitan ester in reducing the tackiness of the films obtained from aqueous acrylic polymer dispersions (Eudragit), compared with those of talc and glyceryl monostearate (GMS). The results from the peel tests demonstrated that GMS, Span 60 and Span 40 could significantly reduce the tackiness of both Eudragit NE 30D and Eudragit RS 30D films. The mechanisms in reducing the film tackiness were investigated by analyzing the film compositions, using attenuated total internal reflectance infrared spectroscopy (ATR-IR) and optical microscopy. The storage modulus of the films was also examined. The results indicated that GMS, Span 60, and Span 40 could reduce the film tackiness by decreasing the polymer contents at the film surfaces, resulting in a notable reduction in the contact area of the polymers between the surfaces. The use of only 5% (w/w) of either GMS, Span 60 or Span 40 in the coating formulations is enough to prevent pellet agglomeration without adverse effects on film flexibility. The pellets coated with Eudragit RS 30D/RL 30D (9:1, w/w) did not exhibit any difference in the drug release profiles when either 100% (w/w) talc or 5% (w/w) GMS was used, whereas the formulations containing Span 60 or Span 40 gave a slightly faster release rate.     

Mechanical Properties of Dry and Wet Cellulosic and Acrylic Films Prepared from Aqueous Colloidal Polymer Dispersions Used in the Coating of Solid Dosage Forms

The mechanical properties of dry and wet polymeric films prepared from various aqueous polymeric dispersions were evaluated by a puncture test. They were studied with respect to type of polymer dispersion [cellulosic: Aquacoat and Surelease; acrylic: Eudragit NE, L, RS, and RL 30 D], plasticizer type (water-soluble or water-insoluble), drying or curing conditions, method of film preparation (pseudolatex- vs solvent casting) and ratio of Eudragit RS/RL 30 D in mixed Eudragit RS/RL films. Dry and wet mechanical strengths of the polymeric films depended primarily on the types of the colloidal polymer dispersion and the plasticizer. Films prepared from ethylcellulose dispersions resulted in very weak and brittle films when compared to the acrylic films. Pseudolatex-cast ethylcellulose films showed lower puncture strength and elongation values when compared to those of the solvent-cast films. Curing of the pseudolatex-cast ethylcellulose films had minimal effects on their mechanical properties. Eudragit L 30D, an enteric polymer dispersion, resulted in brittle films in the dry state, but in very flexible films in the wet state because of the plasticization effect of water. Wet Eudragit RS 30 D polymer films plasticized with water-insoluble plasticizers were significantly more flexible than the corresponding wet films plasticized with water-soluble plasticizers. The water-soluble plasticizers leached from the films during exposure to the aqueous medium, while the water-insoluble plasticizers were almost completely retained within the wet films. The low permeability of a water-soluble drug, chlorpheniramine maleate, and the weak mechanical properties of Aquacoat films could suggest osmotic driven/rupturing effects as the release mechanisms from Aquacoat-coated dosage forms.     

Dry polymer powder coating and comparison with conventional liquid-based coatings for Eudragit) RS, ethylcellulose and shellac.

Drug-layered pellets were coated with micronized polymer powders (Eudragit) RS, ethylcellulose, and shellac) by a dry powder coating technique as an alternative to organic- and aqueous-based coatings (Eudragit) RS 30D, Aquacoat) ECD) were investigated. High plasticizer concentrations (40%) and a thermal after-treatment (curing) were necessary for the coalescence of the polymer particles and good film formation. Ethylcellulose required a higher curing temperature and time than Eudragit) RS because of its higher glass transition temperature (133 versus 58 degrees C). A smaller polymer particle size also promoted film formation. In general, pellets coated with polymer powders required higher coating levels to obtain similar drug release patterns as pellets coated with organic polymer solutions and aqueous polymer dispersions.     

Effect of pectinolytic enzymes on the theophylline release from pellets coated with water insoluble polymers containing pectin HM or calcium pectinate

Theophylline pellets were coated with cellulosic (Aquacoat ECD 30, Surelease clear) or acrylic (Eudragit NE30D, RS30D) polymer aqueous dispersions, containing 10% (related to the insoluble polymer content) of pectin HM or calcium pectinate, using a Uni-Glatt fluidized-bed coating apparatus. When commercial pectinolytic enzymes were added to the dissolution media (0.05 M acetate - phosphate buffer, pH 6.0), the release of theophylline from the coated pellets was generally slower than that observed in the media without enzymes. The enzymatic slowing down of the drug release, depending on the type of the aqueous polymer dispersion used, is more important with mixed Eudragit NE/calcium pectinate coated pellets. The results obtained have been examined with regard to the validity of the approach based on the combination of pectins and the insoluble polymer aqueous dispersions intended for specific-delivery of drugs to the colon. The mechanism of the hydrophilic drug release from pellets coated with insoluble polymer aqueous dispersions containing an aqueous gel-forming polymer has been also discussed.     

A new process control strategy for aqueous film coating of pellets in fluidised bed.

The parameters with effect on maximum spray rate and maximum relative outlet air humidity when coating pellets in a fluidised bed were investigated. The tested variables include type of water based modified release film coating (Eudragit NE 30D, Eudragit RS 30D, Aquacoat ECD) coating principle (top spray, bottom spray), inlet air humidity and type of pellets (sugar spheres, microcrystalline cellulose pellets). The maximum spray rate was not influenced by the coating principles. The highest spray rate was obtained for the film polymer with the lowest tackiness which is assumed to be the controlling factor. The type of pellets affected the maximum spray rate. A thermodynamic model for the coating process is employed throughout the process and not just during steady state. The thermodynamic model is incorporated into a new process control strategy. The process control strategy is based on in-process calculation of degree of utilisation of the potential evaporation energy (DUE) of the outlet air and the relative outlet air humidity (RH). The spray rate is maximised using set points of DUE and RH as control parameters. The product temperature is controlled simultaneously by regulating the inlet air temperature.     

Influence of film additives on stabilizing drug release rates from pellets coated with acrylic polymers.

The objective of this study was to investigate the influence of talc and triethyl citrate (TEC) on stabilizing the drug release rates following curing and storage at elevated temperature of pellets coated with an aqueous acrylic polymeric dispersion. Core pellets containing anhydrous theophylline (20%), microcrystalline cellulose, and polyvinylpyrrolidone were prepared by extrusion-spheronization. The aqueous dispersions were prepared by adding up to 30% TEC as a plasticizer and talc up to 200% as an antiadherent to a mixture of Eudragit RS 30D/RL 30D (95:5). The theophylline pellets were coated in a fluidized-bed coating unit and then cured at elevated temperatures. Theophylline pellets were successfully coated with the Eudragit dispersions that contained up to 200% talc, based on the dry polymer weight, and the coating efficiency was greater than 93%. Our results demonstrated that the polymer, which was plasticized by TEC, was able to function as a film-forming agent for dispersions containing high levels of talc. No sticking of the coated pellets was observed during the coating process or during the curing or equilibrating phase, even with high levels of TEC in the film. The dissolution rate of theophylline from the coated pellets was delayed when the film coating dispersion contained high levels of talc. Additionally, the stability of the drug release profiles from the coated pellets after storage was significantly improved. Furthermore, a modified dissolution testing used to simulate mechanical stresses that may be encountered in vivo showed the film coated pellets would have sufficient strength. The results of this study demonstrated that high levels of film additives in the acrylic dispersion contributed to the stabilization of the drug release rates as well as the reproducibility of the coating process.     

Influence of relative humidity on the mechanical and drug release properties of theophylline pellets coated with an acrylic polymer containing methylparaben as a non-traditional plasticizer.

The purpose of this study was to investigate the influence of relative humidity (RH) on the mechanical and dissolution properties of theophylline pellets coated with Eudragit((R)) RS 30 D/RL 30 D containing methylparaben (MP) as a non-traditional plasticizer. The coated beads were stored at 23 degrees C and at different relative humidities (0, 29, 51, 75 and 84% RH). The effect of storage conditions on the rate of drug release from coated beads was determined in pH 7.4 phosphate buffer solution. The mechanical properties, including tensile strength and Young's modulus, of individual beads were determined by a diametral compression method with a Chatillon((R)) tension/compression apparatus. The morphology of the intact and fractured beads was investigated using scanning electron microscopy (SEM). The moisture content of the polymeric films was determined using a Karl Fischer coulometric moisture analyzer. The results from the mechanical studies demonstrated that an increase in the relative humidity resulted in a decrease in the tensile strength and Young's modulus of the coated beads. SEM photographs showed that coated beads stored at 0% RH exhibited brittle fracture failure. The coated beads stored at 84% RH showed ductile behavior, which was attributed to the hydroplasticization effect on the acrylic polymer due to the uptake of moisture. The moisture content in the films was also shown to influence the rate of drug release from Eudragit((R)) RS 30 D/RL 30 D coated beads containing MP as the plasticizer. The change in release profiles could be minimized when the relative humidity was reduced to zero. The dissolution rate of theophylline from the coated beads decreased when stored at high relative humidities. This trend was reversed when the coated beads that were stored at 84% RH for 5 weeks, were then equilibrated at 0% RH.     

Non-traditional plasticization of polymeric films

The objective of this study was to investigate the influence of methylparaben, ibuprofen, chlorpheniramine maleate and theophylline on the thermal and mechanical properties of polymeric films of Eudragit RS 30 D. The effects of methylparaben and ibuprofen in the film coating on the rate of drug release from Eudragit RS 30 D coated beads were also studied. The physical and mechanical properties of the cast films and coated beads were investigated using thermal analysis, tensile testing, X-ray diffraction analysis and dissolution testing. The results demonstrated that the glass transition temperature of the Eudragit RS 30 D decreased with increasing levels of methylparaben, ibuprofen and chlorpheniramine maleate in the film. Theophylline exerted no influence on the thermal properties of the polymer. The higher levels of the ibuprofen and methylparaben incorporated into the film resulted in a decrease in the tensile strength of the film. The decrease in Young's modulus of Eudragit RS 30 D coated beads was attributed to an increase in the flexibility of the polymeric films when the level of methylparaben or ibuprofen in the polymeric dispersion was increased. The dissolution data demonstrated that the rate of release of the ibuprofen from coated beads was decreased by increasing the amount of ibuprofen and methylparaben in the polymeric film coating.     

Characterisation of the mechanical properties of polymer films formed from aqueous polymer dispersions by creep testing

The mechanical properties of films formed from an aqueous dispersion of polymethlymethacrylate (Eudragit NE30D) and as mixture with an aqueous dispersion of ethylcellulose (Aquacoat ECD30), have been assessed by applying creep tests at different temperatures, using a dynamic mechanical analyser. In the region of linear creep, the film prepared from 100% Eudragit was far less elastic than when 60% Aquacoat was present. In this region, when the applied stress was doubled, the strain response was doubled. In the non-linear region of behaviour, there is clear evidence that the mixed film is more elastic than the film containing only Eudragit.     

The influence of plasticizer on heat-humidity curing of cellulose acetate phthalate coated beads.

The objectives of the present study are to investigate the effect of plasticizer type and level on the curing of cellulose acetate phthalate (CAP) coated beads with and without the presence of humidity. Theophylline beads were coated in a fluidized-bed with CAP dispersion (Aquacoat CPD) plasticized by a water-insoluble plasticizer, diethyl phthalate (DEP), or a water-soluble plasticizer, triethyl citrate (TEC), at various levels. The coated heads were cured at a heat-only condition (50 degrees C for 24 hr) and a heat-humidity condition (50 degrees C/75% RH for 24 hr). Rapid drug release in the acidic media was found for both heat-only and heat-humidity cured beads when plasticizer was not used in the coating dispersion, indicating that the heat-humidity curing is ineffective without the presence of plasticizers. When plasticizer was incorporated in the coating formulations, heat-humidity curing effectively improved the acid resistance of the coated films at all plasticizer levels investigated. The minimum plasticizer level required to obtain enteric release profiles for heat-humidity cured beads coated at an outlet coating temperature of 46 degrees C was 15%. This limit was further decreased when the beads were coated at a lower temperature due to a less plasticizer loss at the lower coating temperature. Between the two plasticizers, less TEC was lost during the coating process, and TEC was more effective compared to DEP with regards to heat-humidity curing at the 10% plasticizer level. The enteric release profiles were reproducible following a 7-day drying period at 40 degrees C for all heat-humidity cured beads that had initially passed the enteric release dissolution test. The rapid leaching of TEC and DEP into the.     

Quality by design, part III: study of curing process of sustained release coated products using NIR spectroscopy

This study investigated the potential of near infrared spectroscopy (NIRS) to assess film coat curing for tablets coated with methacrylate copolymers. The ability of NIRS to monitor film coat curing was studied and compared to conventional methods like differential scanning calorimetry (DSC) and hot-stage microscopy (HSOM). This study showed that variation in the curing temperature and duration affected the NIR spectra for all formulations. These results and the DSC and HSOM results showed that the spectral changes are due to polymer curing. In addition, glass beads, theophylline and orbifloxacin tablets were coated using Eudragit RL, RS, and L 30-D with varying ratios. Principal component analysis (PCA) was performed on the NIR spectra to investigate the effect of curing time and temperature on cast films, uncoated tablets, coated tablets and coated glass beads. Score plots showed that curing duration and temperature affected coated glass beads, uncoated and coated tablets significantly. The amount of drug released at 250 min, and the NIR spectra of cured tablets were used to develop and validate a 7-factor partial least square (PLS) regression calibration for theophylline tablets coated with Eudragit RL:RS 30-D (1:4). This study demonstrated the potential of NIRS in film coat curing and release monitoring.     

Statistical optimisation of diclofenac sustained release pellets coated with polymethacrylic films

The objective of the present study was to evaluate three formulation parameters for the application of polymethacrylic films from aqueous dispersions in order to obtain multiparticulate sustained release of diclofenac sodium. Film coating of pellet cores was performed in a laboratory fluid bed apparatus. The chosen independent variables, i.e. the concentration of plasticizer (triethyl citrate), methacrylate polymers ratio (Eudragit RS:Eudragit RL) and the quantity of coating dispersion were optimised with a three-factor, three-level Box-Behnken design. The chosen dependent variables were cumulative percentage values of diclofenac dissolved in 3, 4 and 6 h. Based on the experimental design, different diclofenac release profiles were obtained. Response surface plots were used to relate the dependent and the independent variables. The optimisation procedure generated an optimum of 40% release in 3 h. The levels of plasticizer concentration, quantity of coating dispersion and polymer to polymer ratio (Eudragit RS:Eudragit RL) were 25% w/w, 400 g and 3/1, respectively. The optimised formulation prepared according to computer-determined levels provided a release profile, which was close to the predicted values. We also studied thermal and surface characteristics of the polymethacrylic films to understand the influence of plasticizer concentration on the drug release from the pellets.     

Dry Powder Coating of Pellets with Micronized Eudragit® RS for Extended Drug Release

PURPOSE: To develop a novel powder coating technology for extended-release pellets based on the acrylic polymer, Eudragit RS. METHODS: A mixture of micronized Eudragit RS plus talc and a liquid feed (plasticizer plus binder solution) were sprayed separately onto propranolol hydrochloride-loaded pellets in a fluidized bed coater. The coated pellets were heat-cured under different conditions (40 degrees C to 60 degrees C, 2 h to 24 h). The coalescence (film formation) of the polymer particles was studied via the determination of the glass transition and the minimum polymer-softening temperatures (MST). The coated pellets were characterized with respect to their morphologic, release, and stability properties. RESULTS: The optimum plasticizer type and concentration and process temperatures could be identified by the determination of the MST. High concentrations of plasticizer (40% based on the polymer) and a thermal treatment were necessary to achieve complete film formation and extended drug release. Curing the pellets resulted in release profiles, which did not change during storage for 3 years. The coated pellets had a smooth, continuous surface and a dense film structure after curing. CONCLUSIONS: This novel coating technique avoids the use of organic polymer solutions or latex dispersions, has short processing times, and results in stable extended-release profiles.     

Dynamic mechanical thermal analysis studies of polymer films prepared from aqueous dispersion

Dynamic Mechanical Thermal Analysis of cast and sprayed films of an aqueous dispersion of polymethyl methacrylate (Eudragit NE30D) and mixtures with an aqueous dispersion of ethylcellulose (Aquacoat ECD-30) has been undertaken. Such analysis allows the identification of glass transition temperatures and the degree of miscibility of the polymers. It was found that the two polymers formed as cast or sprayed films were not miscible but had an optimal composition of 30% of the ethylcellulose dispersion in the polymethyl methacrylate dispersion.     

Use of ion-exchange resins to prepare 100 microm-sized microcapsules with prolonged drug-release by the Wurster process

Ion-exchange resin (IER)--drug complexes were used as core materials to explore their capability to prepare a 100 microm-sized, highly drug-incorporated microcapsule with a prolonged drug release by the Wurster process. Diclofenac sodium was loaded into Dowex 1-X2 fractionated into 200--400 mesh and subsequently microencapsulated with two types of aqueous colloidal polymer dispersion, Aquacoator Eudragit RS30D. The mass median diameter and drug content of the microcapsules thus obtained were 98 microm and 46% with Aquacoat, and 95 microm and 50% with Eudragit RS30D, respectively. Each microcapsule was obtained at a product yield of 94%. The rate of drug release from the microcapsules was highly dependent on the encapsulating materials. For the microcapsules coated with Aquacoat, diclofenac sodium was found to be rapidly released over 4 h, even at a 25 wt% coating level because of cracks on the microcapsule surfaces resulting from the swelling stress of the drug-loaded IER cores. In contrast, significantly prolonged drug-release was achieved in the microcapsules prepared with Eudragit RS30D: even such a very low coating level as 3 wt% provided an exceptionally prolonged drug-release over 24 h. The results indicated that the use of IER along with a flexible coating material would be a feasible way to prepare a prolonged release type of microcapsules with a diameter of 100 microm and a drug content of more than 50% by the Wurster process.     

酒石酸美托洛尔缓释微丸的制备及处方因素考察

目的：选用Eudragit RS 30 D与Eudragil RL30D两种包衣材料，制备日服2次的酒石酸美托洛尔缓释徽丸，并对其处方因素进行考察。方法：采用Glatt流化床底喷溶液上药法制备载药微丸，考察缓释聚合物Eudragit RS 30D与Eudragit RL 30D的不同质量配比（2：3，7：3和9：1）、聚合物包衣增重（10％，20％和30％）以及增塑利嗣量（10％，20％和40％）和放置时间对药物释放的影响。结果：当Eudragit RS 30D与Eudragit RL 30D的质量比为9：1，聚合物包衣增重为20％，增塑剂用量为20％时，药物的释放行为符合中国药典对缓释制剂释放度的相关规定。结论：通过调整Eudragit RS 30D与Eudragit RL 30D之间的比例，或提高聚合物包衣增重等手段，能使酒石酸美托洛尔载药徽丸具备较理想的缓释效果。     

Influence of methylparaben as a solid-state plasticizer on the physicochemical properties of Eudragit RS PO hot-melt extrudates.

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 an enteric polymer on drug release rates of theophylline from pellets coated with Eudragit RS 30D

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 degrees 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 Eudragit L 100-55. Theophylline pellets when coated with Eudragit RS 30D containing the enteric polymer Eudragit L100-55 demonstrated no aging effects when stored at elevated temperatures. The overcoating of the pellets with Eudragit RD 100 did not affect the drug release profiles and prevented the particles from agglomerating during curing and storage.     

Study of crystallization of endogenous surfactant in Eudragit NE30D-Free films and its influence on drug-release properties of controlled-release diphenhydramine HCI pellets coated with Eudragit NE30D

This study investigates the crystallization of the endogenous surfactant nonoxynol 100 in Eudragit NE30D-free films during storage and the influences of nonoxynol 100 on the dissolution of diphenhydramine hydrochloric acid (HCL) pellets coated with Eudragit NE30D before and after aging at ambient conditions. Polarizing light microscopy showed that when Eudragit NE30D-free films were stored at ambient conditions, off-white, flower-shaped crystals formed and increased in the polymer film as storage time increased. Also, x-ray diffraction showed polymer crystals in the aged free film. Thermogravimetric analysis showed no evidence of combined volatile molecules with the polymer molecules, and Fourier transformed infrared spectroscopy (FTIR) data suggested the same chemical composition of the polymer before and after phase separation. Further, from normal light microscopy, the appearance of the melting droplets in the polymer film indicated that the polymer molecules did not form the crystals. After the extraction of nonoxynol 100 by water, the free film formed by the water-extracted Eudragit NE30D was found free of the crystals after aging at the same conditions. The combination of the thermogravimetric analysis, FTIR, and microscopy showed that the origin of the crystals in dry Eudragit NE30D-free films came from nonoxynol 100, and not from the polymer molecules themselves. Monitoring by differential scanning calorimeter, it was found that the rates of crystallization of nonoxynol 100 were faster when the films were stored at 30°C and 40°C than when stored at ambient conditions and 45°C. When stored at −5°C, the crystallization rate was nearly zero. As the temperature got closer to melting temperature, the crystallization rate was very low because the system was in a thermodynamically disfavored state. The rate gradually increased and finally passed through a maximum as the crystallization temperature decreased. As the temperature kept decreasing, the crystallization rate became small again and eventually stopped because the system turned into a kinetically disfavored state. Because the phase transition of nonoxynol 100 in Eudragit NE30D occurred at ambient conditions, its influence on the dissolution of diphenhydramine HCL pellets coated with Eudragit NE30D was studied. Three different levels of nonoxynol 100 were used in Eudragit NE30D dispersions to make 3 different batches of Eudragit NE30D film-coated, controlled-release diphenhydramine HCL pellets. The results showed the dissolution rate increased as the level of nonoxynol 100 increased in the coating formula. Compared to the commonly used water-soluble additive human peripheral mononuclear cell, nonoxynol 100 was more effective in enhancing the dissolution of diphenhydramine HCL from pellets coated with Eudragit NE30D. Further study showed that the phase separation of the surfactant during aging tends to stabilize or slightly increase dissolution rates at higher surfactant levels.Key words: Eudragit NE30D, Endogenous Surfactant, Free Film, Diphenhydramine HCL Pellets     

Comparison of physicomechanical properties of films prepared from organic solutions and aqueous dispersion of Eudragit RL

BACKGROUND AND THE PURPOSE OF THE STUDY: Mechanical properties of films prepared from aqueous dispersion and organic solutions of Eudragit RL were assessed and the effects of plasticizer type, concentration and curing were examined. METHODS: Films were prepared from aqueous dispersion and solutions of Eudragit RL (isopropy alcohol-water 9:1) containing 0, 10 or 20% (based on polymer weight) of PEG 400 or Triethyl Citrate (TEC) as plasticizer using casting method. Samples of films were stored in oven at 60°C for 24 hrs (Cured). The stress-strain curve was obtained for each film using material testing machine and tensile strength, elastic modulus, %elongation and work of failure were calculated. RESULTS AND MAJOR CONCLUSION: The films with no plasticizer showed different mechanical properties depending on the vehicle used. Addition of 10% or 20% of plasticizer decreased the tensile strength and elastic modulus and increased %elongation and work of failure for all films. The effect of PEG 400 on mechanical properties of Eudragit RL films was more pronounced. The differences in mechanical properties of the films due to vehicle decreased with addition of plasticizer and increase in its concentration. Curing process weakened the mechanical properties of the films with no plasticizer and for films with 10% plasticizer no considerable difference in mechanical properties was observed before and after curing. For those with 20% plasticizer only films prepared from aqueous dispersion showed remarkable difference in mechanical properties before and after curing. Results of this study suggest that the mechanical properties of the Eudragit RL films were affected by the vehicle, type of plasticizer and its concentration in the coating liquid.