Concentration Of Ethyl Cellulose Research Articles

Preparation and Characterization of Gastro-retentive Sustained Release Microcapsules of Salbutamol Sulphate

The objective of this study was to prepare gastro-retentive microcapsules using solvent evaporation method containing salbutamol sulphate. The effect of various viscosity grades of ethylcellulose (EC) on In vitro drug release and buoyancy was evaluated. The influence of formulation factors (stirring speed, Drug: EC ratio, various viscosity grades of EC) on particle size, encapsulation efficiency, in-vitro release characteristics was studied. FT-IR and DSC studies revealed no interaction between drug and EC. The yields and the encapsulation efficiencies were high for all microcapsule formulations. Floating lag time was zero for all microcapsules prepared with EC 7 cPs whereas EC N50 based microcapsules did not show buoyancyl. EC 18-22 cPs based microcapsules showed zero floating lag time for formulations with drug to EC ratio of 1:1 and 1:1.5 but 1:2 ratio did not exhibit buoyancy. Stirring speed was inversely related to the size of the microcapsules. In-vitro release studies revealed that the drug release was sustained upto 12 h for microcapsules prepared with EC 18-22 cPs and EC N50 whereas EC 7 cPs based microcapsules could not sustain the release for more than 6 h. Stability studies as per ICH guidelines revealed no significant change in drug entrapment efficiency, in vitro buoyancy and in vitro drug release. Hence incorporation of optimum concentration of EC 18-22 cPs (F5) in the formulation of microcapsules by solvent evaporation method proved to be an effective method in achieving desired release behavior and buoyancy.

Pentoxifylline Loaded Floating Microballoons: Design, Development and Characterization.

The floating microballoons have been utilized to obtain prolonged and uniform release in the stomach. The objective of the present study involves design, development, and characterization of pentoxifylline loaded floating microballoons to prolong their gastric residence time. Pentoxifylline (trisubstituted xanthine derivative) loaded microballoons were prepared by the solvent evaporation technique using different concentrations of polymers like HPMC K4M and ethyl cellulose (EC) in ethyl alcohol and dichloromethane organic solvent system. Microballoons were characterized for their particle size, surface morphology, production yield, loading efficiency, buoyancy percentage, and in vitro drug release studies. From the characterization it was observed that increases in amount of polymers (HPMC K4M and EC) led to increased particle size, loading efficiency, and buoyancy percentage, and retarded drug release. The particle size, particle yield, loading efficiency, buoyancy percentage and in vitro drug release for optimized formulation (F3) were found to be 104.0 ± 2.87 µm, 80.89 ± 2.24%, 77.85 ± 0.61%, 77.52 ± 2.04%, and 82.21 ± 1.29%, respectively. The data was fitted to different kinetic models to illustrate its anomalous (non-Fickian) diffusion. The in vitro result showed that formulations comprised of varying concentrations of ethyl cellulose in higher proportion exhibited much retarded drug release as compared to formulations comprised of higher proportion of varying concentrations of HPMC K4M.

Ethylcellulose solvent substitution method of preparing heat resistant chocolate

In the present study a structuring technique was developed to produce chocolate which resists deformation at temperatures above 40°C. It was hypothesized that by adding ethylcellulose (EC) solubilized in ethanol (EtOH) to chocolate and evaporating the EtOH an organogel could be formed in situ with the fat phase of the chocolate. Heat resistant chocolate (HRC) was produced by mixing a 20% EC in EtOH solution with molten chocolate. The EtOH was evaporated and the resulting chocolate was incubated at 40°C for 2h and tested for hardness. The effect of various EC viscosities (4, 10, 20, 22, and 45cP) and concentrations ranging from 1.0 to 2.2% on different types of chocolates was studied. Milk chocolate containing 1.9% EC had a hardness of 26.0N whereas the control chocolate was too soft to be tested. Further experiments revealed that white and dark chocolates had hardnesses of 29.5 and 10.5N, respectively. The hardness of the chocolate was dependent on the chocolate formulation and concentration of EC, and independent of EC viscosity. It was observed that the addition and evaporation of EtOH from the compound milk chocolate samples led to an increase in the lightness of the chocolate surface if the EtOH was evaporated at temperatures of 40°C or higher. Addition of EC to chocolate represents a new strategy for the manufacture of HRC. Future work should focus on determining the mechanism by which heat resistance is achieved in these chocolates.

Development and evaluation of diltiazem hydrochloride controlled-release pellets by fluid bed coating process

The aim of the present study was to develop controlled-release pellets of diltiazem HCl with ethyl cellulose and hydroxylpropyl methylcellulose phthalate as the release rate retarding polymers by fluid bed coating technique. The prepared pellets were evaluated for drug content, particle size, subjected to Scanning Electron Microscopy (SEM) and Differential Scanning Calori metry (DSC), and evaluated for in vitro release. Stability studies were carried out on the optimized formulations for a period of 3 months. The drug content was in the range of 97%-101%. The mean particle size of the drug-loaded pellets was in the range 700-785 μm. The drug release rate decreased as the concentration of ethyl cellulose increased in the pellet formulations. Among the prepared formulations, FDL10 and FDL11 showed 80% drug release in 16 h, matching with USP dissolution test 6 for diltiazem HCl extended-release capsules. SEM photographs confirmed that the prepared formulations were spherical in nature with a smooth surface. The compatibility between drug and polymers in the drug-loaded pellets was confirmed by DSC studies. Stability studies indicated that the pellets were stable.

Evaluation of droplet size distributions using univariate and multivariate approaches

Pharmaceutically relevant material characteristics are often analyzed based on univariate descriptors instead of utilizing the whole information available in the full distribution. One example is droplet size distribution, which is often described by the median droplet size and the width of the distribution. The current study was aiming to compare univariate and multivariate approach in evaluating droplet size distributions. As a model system, the atomization of a coating solution from a two-fluid nozzle was investigated. The effect of three process parameters (concentration of ethyl cellulose in ethanol, atomizing air pressure, and flow rate of coating solution) on the droplet size and droplet size distribution using a full mixed factorial design was used. The droplet size produced by a two-fluid nozzle was measured by laser diffraction and reported as volume based size distribution. Investigation of loading and score plots from principal component analysis (PCA) revealed additional information on the droplet size distributions and it was possible to identify univariate statistics (volume median droplet size), which were similar, however, originating from varying droplet size distributions. The multivariate data analysis was proven to be an efficient tool for evaluating the full information contained in a distribution.

A Comparative Study of Acyclovir icroencapsulation by Novel Solvent Evaporation-Matrix Erosion and Spray Drying Techniques

Designing and evaluating a multiparticulate controlled release dosage form, to increase the efficacy of acyclovir (a selective antiherpes agent). Spray drying technique for microsphere production is compared with novel solvent evaporation-matrix erosion technique for variable drug loading in different concentration of ethyl cellulose. The microspheres were characterized for physicochemical properties. The microspheres sizes were ranged from 7-25 μm. The spray dried microspheres had better encapsulation efficiency (up to 91%) compared to that of novel solvent evaporation-matrix erosion technique microspheres. Scanning electron microscopy confirmed spherical geometry due to high cross-linking density. Differential scanning calorimetry, Fourier-transform infrared spectroscopy and x-ray diffraction studies showed chemical stability and intactness of entrapped drug in the microspheres. In vitro release of acyclovir from spray dried microspheres continued for longer period compared to novel solvent evaporation-matrix erosion method. Overall, the release studies depended on the concentration of ethyl cellulose, extent of drug loading, and the technique used to prepare microspheres. Thus, marked retardation of drug release may provide a useful effective anti-retroviral drug therapy.

Understanding Interfacial Behavior of Ethylcellulose at the Water–Diluted Bitumen Interface

An environmentally friendly and commercially available polymer, ethylcellulose (EC), was found to be effective for water removal from water-in-diluted-bitumen emulsions. In a previous study, atomic force microscopy images of bitumen films transferred from the water–toluene interface onto a silicon wafer revealed progressive disruption of bitumen films by increasing the addition of EC. The in situ micropipet experiments, on the other hand, demonstrated the flocculation and enhanced coalescence of two approaching water droplets at low and high EC concentrations, respectively. In this study, we investigated the effect of EC addition on compressibility, composition, thickness, and surface properties of the interfacial films formed by surface-active components of bitumen, aiming to understand the interfacial behavior of EC at the water–diluted bitumen interface. The pressure–area isotherms of Langmuir interfacial films indicated a transformation of a rigid interfacial film formed by surface-active components o...

Grafting of LiAMPS on ethyl cellulose: a route to the fabrication of superior quality polyelectrolyte gels for rechargeable Lithium ion batteries

New types of semi-interpenetrating polymer gel electrolytes with high conductivity as well as strength for use in rechargeable Lithium polymer batteries are synthesized. Single ion conducting polyelectrolyte gels are made by first synthesizing grafted linear chains of Lithium salt of 2-acrylamido-2-methylpropane sulphonic acid on ethyl cellulose (EC) using free radical initiator azobis (cyclohexanecarbonitrile) in dimethyl acetamide solvent, then copolymerizing methyl methacrylate (MMA) and a crosslinking agent ethyleneglycol dimethacrylate to form semi-interpenetrating network. The effect of concentrations of EC and MMA on electrical conductivity and mechanical strength of gels are determined.

Asymmetric membrane osmotic capsules for terbutaline sulphate

The aim of the present study was to design an asymmetric membrane capsule, an osmotic pump-based drug delivery system of ethyl cellulose for controlled release of terbutaline sulphate. asymmetric membrane capsules contains pore-forming water soluble additive, sorbitol in different concentrations in the capsule shell membrane, which after coming in contact with water, dissolves, resulting in an in situ formation of a microporous structure. The terbutaline sulphate is a β-adrenoreceptor agonist widely used in the treatment of asthma. The oral dosage regimen of terbutaline sulphate is 5 mg twice or thrice daily, the plasma half-life is approximate 3-4 h and it produces GI irritation with extensive first pass metabolism. Hence, terbutaline sulphate was chosen as a model drug with an aim to develop controlled release system. Different formulations of ethyl cellulose were prepared by phase inversion technique using different concentrations of sorbitol as pore forming agent. It was found that the thickness of the prepared asymmetric membrane capsules was increased with increase in concentration of ethyl cellulose and pore forming agent, i.e. sorbitol. The dye release study in water and 10% sodium chloride solution indicates that, the asymmetric membrane capsules follow osmotic principle to release content. The pores formed due to sorbitol were confirmed by microscopic observation of transverse section of capsule membrane. Data of in vitro release study of terbutaline sulphate from asymmetric membrane capsules indicated that, the capsules prepared with 10% and 12.5% of ethyl cellulose and 25% of sorbitol released as much as 97.44% and 76.27% in 12 h, respectively with zero order release rate. Hence asymmetric membrane capsule of 10% ethyl cellulose and 25% of sorbitol is considered as optimum for controlled oral delivery of terbutaline sulphate.

Sustained release of ethyl cellulose micro-particulate drug delivery systems prepared using electrospraying

Sustained-release ethyl cellulose (EC) micro-particles were prepared by electrospraying. Ketoprofen (KET) was taken as a model drug and various concentrations of EC functioned as a rate-controlling polymer. The morphology of the micro-particles was assessed using SEM. Images showed that as EC content increased, the granules shared similar surface characteristics containing pure EC. Micro-particle structures were analyzed by DSC, XRD, and FTIR. It was noted that the crystalline drug was converted into an amorphous form in all the granulations and that there was chemical interaction between KET and EC observed from FTIR. Dissolution studies revealed that as the amount of EC increased, the drug release rate decreased. This investigation suggests that electrospraying can be exploited as a useful tool for developing novel particulate drug delivery systems.

Rheological and mechanical properties of oleogels based on castor oil and cellulosic derivatives potentially applicable as bio-lubricating greases: Influence of cellulosic derivatives concentration ratio

Nowadays the lubricating market is demanding new biodegradable or more environmentally acceptable products based on renewable resources as a consequence of progressively more strict environmental regulations. In this framework, this study deals with the design of gel-like dispersions potentially applicable as environmentally friendly lubricating greases. These dispersions were formulated using castor oil and ethyl cellulose/α-cellulose or ethyl cellulose/methyl cellulose blends. In particular, the influence of cellulosic derivatives concentration ratio on the linear viscoelasticity and mechanical stability of the resulting oleogel formulations was studied. The modification of ethyl cellulose/α-cellulose or ethyl cellulose/methyl cellulose weight ratios allows obtaining some formulations with suitable rheological characteristics and mechanical stability for potential lubricating applications. An important decrease in the values of the linear viscoelasticity functions down to a minimum value was found by increasing ethyl cellulose/α-cellulose or ethyl cellulose/methyl cellulose weight ratios ( W) up to a critical value, which depends on both nature of the cellulosic derivatives employed and temperature. Above this critical value, the linear viscoelastic functions increase with W, at temperatures in the range 0–75 °C, and continuously decrease at higher temperatures, i.e. 125 °C. Thermal susceptibility is significantly dampened by reducing ethyl cellulose concentration. Gel-like dispersions formulated with ethyl cellulose/methyl cellulose blends showed appropriate mechanical stabilities to be used as bio-lubricating greases.

Development and evaluation of injection-molded sustained-release tablets containing ethylcellulose and polyethylene oxide

Purpose: It was the aim of the present study to develop sustained-release matrix tablets by means of injection molding of ethylcellulose (EC) and polyethylene oxide (PEO) mixtures and to evaluate the influence of process temperature, matrix composition, and viscosity grade of EC and PEO on processability and drug release. Methods: Formulations consisting of metoprolol tartrate (MPT, concentration: 30%), EC plasticized by dibutyl sebacate, and PEO were extruded and consequently injection molded into tablets. The influence of process temperature (120°C and 140°C), matrix composition, viscosity grade of EC (4, 10, 20, 45, and 100 mPa·s) and PEO (7 × 106, 1 × 106, and 1 × 105 Mw) on processability and drug release was determined. Results: Formulations consisting of 70% EC and 30% MPT showed incomplete drug release, whereas drug release was too fast for formulations without EC. Higher PEO concentrations increased drug release. Formulations containing 30% metoprolol, EC, and different concentrations of PEO showed first-order release rates with limited burst release. Drug release from direct compressed tablets showed faster drug release rates compared to injection-molded formulations. There was no clear relationship between the molecular weight of EC and drug release. The melting endotherm (113.9°C) of MPT observed in the differential scanning calorimeter thermogram of the tablets indicated that a solid dispersion was formed which was confirmed by X-ray diffractogram. X-ray tomography demonstrated a difference in pore structure between tablets processed at 120°C and 140°C. Conclusion: It was concluded that injection molding can be applied successfully to develop sustained-release PEO/EC matrix tablets.

Optimization of a novel wax matrix system using aminoalkyl methacrylate copolymer E and ethylcellulose to suppress the bitter taste of acetaminophen

The purpose of the present study was to design and evaluate a novel wax matrix system containing various ratios of aminoalkyl methacrylate copolymer E (AMCE) and ethylcellulose (EC) as functional polymers in order to achieve the optimal acetaminophen (APAP) release rate for taste masking. A two factor, three level (3 2) full factorial study design was used to optimize the ratios of AMCE and EC, and the release of APAP from the wax matrix was evaluated using a stationary disk in accordance with the paddle method. The disk was prepared by congealing glyceryl monostearate (GM), a wax with a low melting point, with various ratios of polymers and APAP. The criteria for release rate of APAP from the disk at pH 4.0 and pH 6.5 were calculated to be more than 0.5017 μg/(ml·min) and less than 0.1414 μg/(ml·min), respectively, under the assumption that the particle size of spherical matrix should be 100 μm. In multiple regression analysis, the release of APAP at pH 4.0 was found to increase markedly as the concentration of AMCE increased, whereas the release of APAP at pH 6.5 decreased as the EC concentration increased, even when a high level of AMCE was incorporated. Using principle component analysis, it was found that the viscosity of the matrix affects the pH-dependent release of APAP at pH 4.0 and pH 6.5. Furthermore, using multiple regression analysis, the optimum ratio of APAP:AMCE:EC:GM was found to be 30:7:10:53, and the release pattern of APAP from the optimum wax formulation nearly complied with the desired criteria. Therefore, the present study demonstrated that the incorporation of AMCE and EC into a wax matrix system enabled the appropriate release of APAP as a means of taste masking.

Spray Dried Sustained Release Solid Dispersion of Venlafaxine Hydrochloride

Sustained release solid dispersion of venlafaxine hydrochloride, an antidepressant agent, was prepared by the spray drying technique using various concentration of ethyl cellulose. Characterization was done using thermal analysis (DSC), X-ray diffraction (XRD) and infrared spectroscopy (FTIR). Drug content and dissolution rate studies and its kinetics were also performed. Dissolution studies revealed that the drug release from the solid dispersion matrix was significantly reduced.

Development of ethylcellulose-polyethylene glycol and ethylcellulose-polyvinyl pyrrolidone blend oral microspheres of ibuprofen

Ibuprofen (IBP) was successfully encapsulated in ethylcellulose (EC) microspheres by oil-in-water solvent evaporation method. Dichloromethane (DCM) was used as the dispersed phase and distilled water was used as a dispersing medium. The objective of this work was to develop and observe the effect of formulation parameters on the physical characteristics of the resulting microspheres. The percent recovery of microspheres, their hydration rate, IBP loading efficiency and the drug release rate from microspheres were analyzed. Almost spherical microspheres having an encapsulation efficiency of 90-99 % were obtained. The drug release was also controlled to a great extent by the addition of water soluble polymers polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP). Decreasing the concentration of EC in the dispersed phase decreased the recovered weight. But this decrease in polymer concentration and increase of pore formers like PEG and PVP increased the release rate of the drug from microspheres, their hydration, drug loading as well as encapsulation efficiency. FTIR and XRD confirmed the absence of drug polymer interaction and amorphous state of drug after encapsulation. Moreover, the release pattern did not show any burst effect indicating that the absence of free ibuprofen on the surface of formed microspheres and formulations containing PVP provide better control release than PEG containing formulation. Drug release mechanism at pH 6.8 in all formulations is anomalous except the formulation containing 400 mg of PEG as channeling agent, which shows super case II transport.

Ethyl Cellulose Microcapsules for Protecting and Controlled Release of Folic Acid

Ethyl cellulose microcapsules were developed for use as a drug-delivery device for protecting folic acid from release and degradation in the undesirable environmental conditions of the stomach, whilst allowing its release in the intestinal tract to make it available for absorption. The controlled release folic acid-loaded ethyl cellulose microcapsules were prepared by oil-in-oil emulsion solvent evaporation using a mixed solvent system, consisting of a 9:1 (v/v) ratio of acetone:methanol and light liquid paraffin as the dispersed and continuous phase. Span 80 was used as the surfactant to stabilize the emulsion. Scanning electron microscopy revealed that the microcapsules had a spherical shape. However, the particulate properties and in vitro release profile depended on the concentrations of the ethyl cellulose, Span 80 emulsifier, sucrose (pore inducer), and folic acid. The average diameter of the microcapsules increased from 300 to 448 microm, whilst the folic acid release rate decreased from 52% to 40%, as the ethyl cellulose concentration was increased from 2.5% to 7.5% (w/v). Increasing the Span 80 concentration from 1% to 4% (v/v) decreased the average diameter of microcapsules from 300 to 141 microm and increased the folic acid release rate from 52% to 79%. The addition of 2.5-7.5% (w/v) of sucrose improved the folic acid release from the microcapsules. The entrapment efficiency was improved from 64% to 88% when the initial folic acid concentration was increased from 1 to 3 mg/ml.

Multiple Unit Asymmetric Membrane Capsule: A Means for Delivery of Highly Water Soluble Drug

A multiple unit, non-disintegrating asymmetric polymeric capsular system was used to deliver highly water-soluble drug in a controlled manner. A highly water-soluble drug, metformin hydrochloride (MHCl), was selected as a model drug to demonstrate how the controlled release could be generated in vitro by changes in the core as well as the coating formulation. Formation of asymmetric capsule wall membrane involved wet phase inversion process, in which the asymmetric membrane (AM) was precipitated on glass mold pins by dipping the mold pins into a coating solution containing the good and bad solvents for the polymer followed by quenching in an aqueous quench bath. The study optimized by 23 factorial design evaluates the influence of coating formulation namely concentration of ethylcellulose and pore former (glycerol) and core component namely controlled release potassium chloride crystals. Scanning Electron Microscopy (SEM) showed the presence of outer dense non porous region and inner, thick, porous region for the prepared AM. Statistical test were applied at P > 0.05 on all the formulations undergoing in vitro release studies. Results showed the solubility of MHCl to have been modulated (reduced) over an extended period of time with pH independent, and osmotic pressure dependant drug release. The release kinetics was found to be zero order.

Development and in vitro evaluation of floating rosiglitazone maleate microspheres

Background: Various approaches have been used to retain the dosage form in stomach as a way of increasing the gastric residence time, including floatation systems; high-density systems; mucoadhesive systems; magnetic systems; unfoldable, extensible, or swellable systems; and superporous hydrogel systems. Aim : The objective of this study was to prepare and evaluate floating microspheres of rosiglitazone maleate for the prolongation of gastric residence time. Method: The microspheres were prepared by solvent diffusion–evaporation method using ethyl cellulose and hydroxypropylmethylcellulose. A full factorial design was applied to optimize the formulation. Results: Preliminary studies revealed that the polymer:drug ratio, concentration of polymer, and stirring speed significantly affected the characteristics of microspheres. The optimum batch exhibited a prolonged drug release, remained buoyant for >12 hours, high entrapment efficiency, and particle size in the order of 350 μm. Conclusion: The results of 32 full factorial design revealed that the concentration of ethylcellulose 7 cps (X1) and stirring speed (X2) significantly affected drug entrapment efficiency, percentage release after 8 h and particle size of microspheres.

Novel drug delivery devices for providing linear release profiles fabricated by 3DP

Novel doughnut-shaped multi-layered drug delivery devices (DDDs) were developed with local variations of the drug and release-retardant material for providing linear release profiles. Based on computer-aided design models, different DDDs containing acetaminophen as a model drug, hydroxypropyl methylcellulose as matrix and ethyl cellulose (EC) as a release-retardant material were prepared automatically using a three-dimensional printing (3DP) system. In vitro dissolution assays demonstrated that all the 3DP DDDs had with different diameters, heights, concentrations of EC and central hole diameters were able to give linear release profiles. Morphological and erosion studies showed that acetaminophen was released through a simultaneous surface erosion process involving the outer peripheries and inner apertures. The barrier layers on both bases of DDDs had good adhesion strength with the drug-contained regions and offered consistent release retardation for the whole duration of the dissolution process. The release time periods of the DDDs were dependent on the annular thicknesses or the passes of binder solution containing a release-retardant material. The dosage of the DDD can be adjusted independently by changing the heights of the DDDs. Thus, 3DP is capable of offering novel strategies for developing DDDs with complex design features for desired drug release profiles.

Controlled Indomethacin Release from Mucoadhesive Film: <i>In Vitro</i> and Clinical Evaluations

To develop a film formulation allowing controlled release for long-term analgesia, we selected ethyl cellulose (EC) as a novel additive, prepared a film formulation using indomethacin (IM film), and evaluated it in vitro and clinically. In the in vitro experiments, the effects of the EC concentration on the release rate of IM and on the adhesion force to the mucous membrane were investigated. The addition of 10% EC resulted in more sustained slow release compared with no EC, and the adhesion of the film with 10% EC added was similar to that of films containing carboxyvinyl polymer, which we reported previously showed significantly increased adhesion. A two-layered film consisting of an adhesive layer with 2% or 1% IM and 10% EC and a nonadhesive layer with 2% polyethylene glycol as a softening agent, was investigated for clinical use. Film consisting of an adhesive layer with 2% IM and 10% EC exhibited rapid onset of potent analgesia and was expected to prolong the duration of analgesia. These results suggest that IM film with EC added may be useful clinically, since it shows both immediate analgesic effects and prolonged duration of release.