Amount Of Ethyl Cellulose Research Articles

FORMULATION AND OPTIMIZATION OF MUCOADHESIVE MICROSPHERES OF VALSARTAN BY USING BOX-BEHNKEN DESIGN

Objective: The purpose of this study was to formulate and optimize mucoadhesive microspheres of antihypertensive drug (valsartan) within ethyl cellulose as a carrier polymer and carbopol 934P as a mucoadhesive polymer for controlling the release of valsartan.
 Methods: The emulsion solvent evaporation technique was used for preparation of microspheres of valsartan and the Box-Behnken design was employed with thee independent variables that is amount of ethyl cellulose (X1) and amount of carbopol 934P (X2) and stirring speed (X3) and evaluate four dependent variables such as percentage mucoadhesion, Q1 h, t90% and drug entrapment efficiency.
 Results: The optimum conditions were found to be X1= 200 mg, X2= 107 mg and X3= 1200rpm. The optimized batch exhibited a high drug entrapment efficiency of 85.63±1.384%, percentage mucoadhesion was 66.76±0.986% and drug release was also sustained for more than 12 h.
 Conclusion: The analysis of variance showed a significant effect of independent variables. The scaning electron microscopy (SEM) analysis showed that the microspheres were spherical and free-flowing. The microspheres of valsartan were stable after thee month stability study at accelerated condition.

Chronotherapeutic Drug Delivery of Ketoprofen and Ibuprofen for Improved Treatment of Early Morning Stiffness in Arthritis Using Hot-Melt Extrusion Technology.

This work developed a chronotherapeutic drug delivery system (CTDDS) utilizing a potential continuous hot-melt extrusion (HME) technique. Ketoprofen (KTP) and ibuprofen (IBU) were used as two separate model drugs. Eudragit S100 (ES100) was the matrix-forming agent, and ethyl cellulose (EC) (2.5 and 5%) was the release-retarding agent. A 16-mm extruder was used to develop the CTDDS to pilot scale. The obtained extrudate strands were transparent, indicating that the drugs were homogeneously dispersed in the matrix in an amorphous form, confirmed by both differential scanning calorimetry and powder X-ray diffraction. The strands were pelletized into 1, 2, and 3mm size pellets. A 100% drug release from 1, 2, and 3mm pellets with 2.5% EC was observed at 12, 14, and 16h, whereas the drug release was sustained for 14, 16, and 22h from 5% EC pellets, respectively, for KTP. The release characteristics of IBU were similar to those of KTP with modest variations in release at lag time. The in vitro drug release study conducted in three-stage dissolution media showed a desired lag time of 6h. The percent drug release from 1, 2, and 3mm pellets with 40% drug load showed < 20% release from all formulations at 6h. The amount of ethyl cellulose and pellet size significantly affected drug release. Formulations of both KTP and IBU were stable for 4months at accelerated stability conditions of 40°C/75% RH. In summary, HME is a novel technique for developing CTDDS.

Utilization of ethyl cellulose polymer and waste materials for roofing tile production

The aim of this study was to utilize ethyl cellulose, mixture of waste engine oil and waste vegetable oil as a binder in the environmental friendly roofing tile production. The waste engine-vegetable oil wasmix together with ethyl cellulose, fly ash, coarse aggregates, fine aggregatesand a catalyst. The Fourier Transform Infrared (FTIR) analysis showed that the oil mixture added with ethyl cellulose has the relatively high binding effect due to the presence of strong carbonyl group especially after being heat cured at 1900C for 24 hours. The mixed proportion of materials with different amount of ethyl cellulose used was studied in the production of tile specimen. The results showed that the ethyl cellulose composed roofing tile specimens passed the transverse breaking strength, durability, permeabilityand the ultraviolet accelerated test. The shrinkage on the tile can be overcome by adding temperature resistance polymer on the exterior of the tile.

Development and Characterization of Thermosensitive intranasal Gel Containing Paliperidone Loaded Microspheres

Purpose: The objective of the present investigation was to fabricate a thermosensitive gel containing paliperidone loaded microspheres for the treatment of schizophrenia for brain delivery through nasal route. Incorporation of drug in to microspheres and then in to gel should increase the duration of release and nasal duration time respectively. Material and Method: Ethyl cellulose microspheres containing paliperidone palmitate were prepared by emulsification of ethyl acetate dispersion containing polymer and drug with aqueous external phase containing polysorbate 80. Amount of ethyl cellulose and polysorbate 80 were identified as critical formulation variables influencing the drug release at critical time points, percentage yield and particle size. These factors were studied using 2 factors and 3 level face centered factorial design using Design Expert ® . Drug-excipient compatibility was ascertained using FTIR analysis. The paliperidone microspheres were then incorporated in to Pluronic F127 and HPMC gel having required thermo sensitive and muco adhesive properties. Gel containing microspheres was subjected to Ex vivo permeation study, irritation study using sheep nasal mucosa and pharmacodynamic study (spontaneous motor activity in mice). Results: Microspheres that could sustain the drug release up to 8 hours were developed. Thermoreversible gel having required thermo sensitive and muco adhesive properties was developed. The Ex vivo permeation study and pharm a codynamic study of the drug loaded microsphere containing gel confirmed the release up to 8 hours. The histopathology study showed absence of irritation on sheep nasal mucosa. Conclusion: Paliperidone palmitate loaded microspheres containing gel could prolong and target the drug release to brain and therefore give prolonged and intense action. Key words: Nose to brain delivery, Paliperidone palmitate, Pharmacodynamic activity, Thermoreversible gel, Desirability index.

Optimization of spray-dried diclofenac sodium-loaded microspheres by screening design

ABSTRACTThe aim of the present study was to investigate the effect of formulation and operating parameters of the laboratory spray dryer on polymeric microspheres intended to be used for sustaining drug delivery of diclofenac sodium (DS). Four operating and four formulation parameters were investigated by Plackett–Burman design to enhance the encapsulation efficiency (EE). The independent variables were air inlet temperature, aspirator, feed flow rate, spray nozzle diameter, amount of drug, amount of polymers, and volume of organic solvent. The resultant microspheres were characterized for their EE. The microspheres having high EE were further characterized for particle size, morphology, and in vitro drug release. Interaction between the drug and the polymer were investigated by Fourier transform infrared (FTIR) spectroscopy and X-ray powder diffractometry (XRPD). The Pareto chart showed that amount of Eudragit® RS100, amount of ethylcellulose, and aspirator were identified as significant factors. The microspheres showed high EE (47.55 ± 0.006% to 67.99 ± 0.007%). The microspheres were found to be discrete, spherical with smooth surface. The FTIR analysis confirmed the compatibility of DS with the polymers without interaction. The XRPD revealed the dispersion of drug within microspheres formulation. The in vitro drug release from these DS-loaded microspheres showed sustained release of DS over a period of 12 h and followed the Korsmeyer–Peppas model [R2 = 0.9920 (Run 1) and 0.9957 (Run 13)] with a value of the slope (n) ≤ 0.43. This n value, however, appears to indicate that Fickian release is the dominant mechanism of drug release with these formulations.

Risk based approach for design and optimization of site specific delivery of isoniazid

The research envisaged focuses on risk management approach for development and optimization of enteric coated tablet of isoniazid giving extended release in pH 6.8 phosphate buffer. Risk assessment using failure mode and effects analysis was done to depict the effects of unambiguous failure modes related to particular formulation/process variable. A 23 full factorial design was employed for optimization of core tablet to investigate effect of amount of Polyox WSR 303 (A), hardness (B) and amount of ethyl cellulose (C) on percent drug release in pH 6.8 phosphate buffer. Main effects and interaction plots were generated to study effects of variables. The selection of optimized formulation was done on overlay contour plots and desirability function. The optimized formulation exhibited percent drug release at first hour of 26.97 %, second hour of 44.20 %, fourth hour of 66.15 % and eighth hour of 97.9 % in phosphate buffer pH 6.8. Akaike information criteria and Model selection criteria revealed that the model was best described by Korsmeyer–Peppas power law. The Kopcha and Peppas–Sahlin model revealed diffusion as predominant mechanism of release which may be due to high solubility of drug and drug loading. Enteric coating optimization revealed weight gain of 10 % w/w as optimum; giving nil release of isoniazid in 0.1 N hydrochloric acid. The composite desirability for optimized formulation computed using equations and software were 0.91 and 0.90 respectively. Capability analysis on reproducibility batches revealed all indices above 1.33 signifying process was within control of producing batches as per desired specifications.

Formulation and Evaluation of Sustained Release Extrudes Prepared via Novel Hot Melt Extrusion Technique

The purpose of the present investigation is to emphasize the application of hot-melt extrusion technique (HMET) for the preparation of sustained release matrix formulation of highly dosed, freely soluble drugs. In this study, sustained release multiple unit dosage of venlafaxine hydrochloride (VH) was prepared by HMET. Custom design was used to screen the effect of four factors-type of polymer (ethylcellulose and eudragit RSPO) (X1), amount of polymer (X2), type of plasticizer (DBS, ATBC, TEC, and PEG) (X3), and plasticizer concentration (X4), on the drug release at 8 h (Y1) and machine torque (Y2). The experiments were carried out according to a four-factor 16-run statistical model and subjected to 12-h dissolution study in purified water. The significance of the model was indicated by ANOVA. Results of in vitro release study indicate that formulations prepared with higher amount of ethylcellulose and DBC show significant retardation at 8 h. The result shows that increase in concentration of polymer with the combination of water insoluble plasticizer (DBS and ATBC) has better sustained release while increasing concentration of TEC and PEG results faster in vitro release. Besides that increase in plasticizer concentration helps in reducing the melt temperature and machine torque. The in vivo study was performed, and formulations were compared using area under the plasma concentration-time curve (AUC0-∞), time to reach peak plasma concentration (Tmax), and peak plasma concentration (Cmax). The drug release profiles of extrudes were found to fit both diffusion and surface erosion models. Further to this, scanning electron microscopy, differential scanning calorimetry, and X-ray diffraction analysis of the hot-melt extrudates demonstrated that VH remained crystalline and was homogeneously dispersed throughout the polymer matrix.

Optimization of Mucoadhesive Microspheres of Acyclovir by Applying 32 Full Factorial Design

The purpose of this research was to formulate and evaluate mucoadhesive microspheres of acyclovir. Acyclovir mucoadhesive microspheres containing ethyl cellulose as carrier polymer and Carbopol 940 as mucoadhesive polymer were prepared by an emulsion solvent evaporation technique. The morphological characteristics of the mucoadhesive microspheres were studied under a scanning electron microscope. Microspheres were discrete, spherical, free flowing and showed a good percentage of drug entrapment efficiency. An in vitro mucoadhesive test showed that acyclovir mucoadhesive microspheres adhered more strongly to the gastric mucous layer and could retain for an extended period of time. A 3 2 full factorial design was employed to study the effect of independent variables, amount of ethyl cellulose (X 1 ) and amount of Carbopol 940 (X 2 ) on dependent variables, i.e. drug entrapment efficiency, Q 1 h , t 90 % and mucoadhesive strength parameter. The amount of ethyl cellulose and Carbopol 940 significantly affected on all selected dependent variables. The optimized batch exhibited a high drug entrapment efficiency of 72 %, Q 1 h 27 %, t 90 % 549 min and mucoadhesion strength 21.2 g. In vitro release of acyclovir was sustained up to 12 h. The formulation was found to be stable after two months stability study at accelerated condition. Overall, the developed formulation was stable with sustain release of acyclovir over 10-12 h periods; hence can be a viable alternative to conventional dosage forms.

Freeze-Dried Highly Porous Matrix as a New Gastroretentive Dosage Form for Ecabet Sodium: In Vitro and In Vivo Characterizations

AbstractThe aims of the present study were to prepare hydroxypropylmethyl cellulose-based matrix tablets prepared using the freeze-drying method for gastroretentive delivery of ecabet sodium (ECS), a locally acting antigastric ulcer drug, and to perform in vitro/in vivo characterizations.The freeze-dried gastroretentive tablets (FD-GRTs) had porous structures, while they had good friability as a pharmaceutical dosage form. The porous structures lowered the tablet density, allowing the tablet to float without any lag time. Buoyancy of FD-GRT was maintained until they were entirely disintegrated during an in vitro release study. Release rate of ECS could be controlled by the amount of ethylcellulose (EC) in FD-GRT. As amount of EC in the composition was increased, there was a decrease in both release rate and erosion rate of FD-GRT. When administered to a miniature pig, FD-GRT remained in the stomach for more than 12h, which was significantly longer than a conventional sustained release tablet. The new FD-GRT do not contain any excipients for buoyancy and do not require any lag time for buoyancy, consequently it could be considered to be safer and more effective than conventional floating-type GRT.

Inkjet Printing of Piezoelectric Lead Magnesium Niobate-Lead Titanate Thick Films

This study shows the fabrication of lead magnesium niobate-lead titanate (PMN–PT) thick-films by inkjet printing on ceramic substrates for the first time. PMN–PT powder, prepared by mechanochemical synthesis, is dispersed in an organic solvent using a three roll mill to form a high-viscosity paste. For printing, the paste is thinned to a low-viscosity ink. Small amounts of ethyl cellulose in the ink prevent sedimentation. Glass particles are added to the paste to improve adhesion on the substrate surface. A two step inkjet-printing process forming homogeneous layers is introduced. After sintering at 950 °C for 2 h, piezoresponse force microscopy (PFM) is used to investigate the piezoelectric response of the printed films.

GASTRO-RETENTIVE FORMULATION OF METOCLOPRAMIDE: DESIGN AND OPTIMIZATION USING D-OPTIMAL DESIGN TECHNIQUE

The purpose of this research was to fabricate and optimize Gastro-retentive drug delivery system for Metoclopramide Hydrochloride. The effect of ethyl cellulose and sodium alginate on the drug release profile and floating properties was evaluated. Sodium carbonate was incorporated as gas generating agent. The addition of ethyl cellulose reduces the drug dissolution rate due to its hydrophobic nature. A D-Optimal Technique was applied systematically to optimize the drug release profile. The amounts of ethyl cellulose (X1) and sodium alginate (X2) were selected as independent variables. The cumulative percent of drug released at 8, 12 and 16 hours were selected as dependent variables. The study shows that, tablet composition and mechanical strength have great influence on floating properties and drug release. All formulations were evaluated for dimensional analysis, duration of buoyancy, floating lag time, drug content and invitro drug release. Optimized formulation’s data was subjected to various release kinetic models. The drug release was sufficiently sustained for 24 hours. Model equations of zero and first order, Higuchi, Hixson-Crowell and Peppas, intended to elucidate the drug release mechanism, were fitted to the release data. The zero order release was observed with r2 values of 0.98. The difference in the release pattern and kinetics can be explained by the different swelling and erosion behaviors.

The prolongation of the in vitro dissolution of a soluble drug (phenethicillin potassium) by microencapsulation with ethyl cellulose.

Microcapsules of phenethicillin potassium as a model water-soluble drug, coated with ethyl cellulose, have been prepared (core: wall ratios 1:1, 1:2 and 1:3) in which the taste has been masked, the odour almost eliminated and the release retarded. Sieve analysis showed that with decreasing core: wall ratios there was a trend towards increasing amounts of larger sized microcapsules. At constant core:wall ratios in vitro release of drug was generally greatest from the larger microcapsules. This result correlated with the surface areas of the microcapsules which became less as the asymmetry of the microcapsules diminished with decrease in microcapsule size. There was a linear relation between the amount of ethyl cellulose and the time for 60% release of drug, and the release pattern was analogous to that from insoluble porous matrices. Scanning electron micrographs showed the microcapsules to be irregularly shaped with circular surface pores, and they did not alter in shape or size during dissolution. Tableting of 1:1 core: wall ratio microcapsules significantly further retarded the dissolution.

Metoprolol Tartrate-Ethylcellulose Tabletted Microparticles: Development of a Validated Invitro In-vivo Correlation

Abstract — This study describes the methodology for the development of a validated in-vitro in-vivo correlation (IVIVC) for metoprolol tartrate modified release dosage forms with distinctive release rate characteristics. Modified release dosage forms were formulated by microencapsulation of metoprolol tartrate into different amounts of ethylcellulose by non-solvent addition technique. Then in-vitro and in-vivo studies were conducted to develop and validate level A IVIVC for metoprolol tartrate. The values of regression co-efficient (R 2 -values) for IVIVC of T2 and T3 formulations were not significantly (p<0.05) different from 1 while the values of R 2 for IVIVC of T1 and Mepressor ® were significantly (p<0.05) different from 1. Internal prediction errors of IVIVC, calculated from observed Area under Curve (AUC) and predicted AUC, were less than 10%. This study successfully presents a valid level A IVIVC for metoprolol tartrate modified dosage forms. Keywords — Metoprolol tartrate, Dissolution, Bioavailability, Validated in-vitro in-vivo correlation.I.

Controlled release multiple layer coatings

Purpose: In a fluid-bed coating machine, the coating solutions are normally sprayed using a manually controlled peristaltic pump. This study provides a process where two or more coating solutions can be sprayed consecutively using two or more syringe pumps controlled by a computer, to form multiple layers. In this process, the spraying parameters can be controlled easily from a computer. Methods: Propranolol HCl was used as a model drug. Nine different drug-loaded controlled release coated beads were prepared by using a combination of ethylcellulose and/or chitosan solutions. The pulse-coated beads were prepared by changing the spray rate and/or volume of the polymer solutions. Results: There was a fourfold increase (18 versus 75 minutes) in lag time when the same amount of ethylcellulose (4 g) was dissolved in 100 mL of ethanol instead of 160 mL. When the same amount of drug and ethylcellulose solution was applied on the acrylic coated beads as multiple layers coating, the lag time decreased to only 6 minutes. Similarly, the 50% drug release time also decreased significantly. Conclusion: An overall comparison of the dissolution profiles showed that drug release from these coated beads was changed significantly when the sequence of the drug and polymer layers was changed.

A novel gel polymer electrolyte based on lithium salt with an ethyl cellulose

A novel gel polymer electrolyte (GPE) that contains Li+ ions was fabricated. An appropriate amount of ethyl cellulose (EC) was added to 1 M lithium perchlorate in propylene carbonate to prepare the GPE. The ionic conductivity (σ) of the GPE depends on the EC content, and the GPE with an EC content of 4.5 wt.% exhibits a maximum σ of 6.47 mS/cm, a viscosity of 141 mPa∙s, and a transmittance of over 80% (visible region) at room temperature. High σ and transparent GPE can be obtained. In this work, the EC was used as natural thickener to enhance the viscosity of the liquid-state electrolyte and could improve the leakage of electrolyte solution.

분산특성이 향상된 고효율 염료감응형 태양전지

nano-particle paste was prepared by ethyl cellulose, -terpineol and bis(2-ethylhexyl) phthalate (dioxcyl phthalate) for dye-sensitized solar cells (DSSCs). Dispersion and absorbance of photoanode films was controlled by adding different amount of ethyl cellulose and -terpineol. The morphology of prepared films was studied by field emission scanning electron microscopy (FE-SEM) and the optical properties of films were measured by UV/vis spectra. Photovoltaic-current density was observed to determine the electrochemical response of DSSCs. Energy conversion efficiency was obtained about 7.1% at ethyl cellulose and -terpineol at optimal mixed ratio (as ethyl cellulose: 0.1 g; -terpineol: 1.5 ml) under illumination with AM 1.5() simulated sunlight.

Use of Ethylcellulose To Control Chlorsulfuron Leaching in a Calcareous Soil

Controlled release formulations (CRFs) have been researched to reduce the water-polluting risk derived from the use of conventional formulations of chlorsulfuron. Coated chlorsulfuron granules were produced in a Wuster-type fluidized-bed equipment using two different amounts of ethylcellulose. The highest one was modified by the addition of a plasticizer such as dibutyl sebacate. The encapsulation efficiency and morphological properties of coated granules having been studied, the chlorsulfuron kinetic release in water was studied. In addition, the mobility of chlorsulfuron in a calcareous soil was finally carried out. High encapsulation efficiency was obtained, being nearly 100% in all cases. SEM pictures show a homogeneous film in coated CRFs; thickness oscillates between 23.32 microm for the system prepared with a 10% of ethylcellulose and 32.61 microm for the system prepared with a 20% ethylcellulose plus plasticizer. The rate of chlorsulfuron release from coated CRFs is diminished in all cases in relation to chlorsulfuron commercial formulation, the latter being completely dissolved in <1 h, but it took at least 50 days to release 90% of chlorsulfuron from the formulation coated with a 20% ethylcellulose plus plasticizer. Using a generic equation, the time taken for 50% of the active ingredient to be released into water (t(50)) was calculated. From the analysis of the t(50) values, it can be deduced that the release rate of chlorsulfuron can be mainly controlled by changing the thickness of the coating film, by modifying the surface properties of the coating film, and by adding a plasticizer. Mobility experiments carried out in calcareous soil show that the use of coated CRFs reduces the presence of chlorsulfuron in the leachate compared to commercial formulation.

Targetry of SrCO 3 on a copper substrate by sedimentation method for the cyclotron production no-carrier-added 86Y

Strontium carbonate deposition on copper substrate was carried out by the sedimentation method in order to produce yttrium-86. Natural strontium carbonate thick layer was prepared with 480 mg SrCO 3, 220 mg ethyl cellulose, and 7.5 mL acetone. This optimum condition is a result of several repeated experiments with different amount of ethyl cellulose and acetone. Target quality control was done by SEM photomicrograph and thermal shock test. The deposited target was irradiated at 30 μA current and 15 MeV proton beam for 12 min.

Controlled-release formulations of cyromazine-lignin matrix coated with ethylcellulose

An encapsulation system was developed and designed to give long-lasting effectiveness of the insect growth regulator cyromazine. Cyromazine was incorporated in lignin-poly (ethylene glycol) (PE) controlled-release formulations by means of a melting process. The basic formulation [lignin (65%)–PE (20%)–cyromazine (15%)] was coated in a Wurster-type fluidized-bed equipment using two different amounts of ethylcellulose. That of the highest one was modified by the addition of a plasticizer, dibutyl sebacate (DBS). The effect on cyromazine release rate caused by the incorporation of ethylcellulose and DBS in lignin-PE formulation was studied by immersion of the granules in water under static conditions. Using an empirical equation, the time taken for 50% of the active ingredient to be released into water (T50) was calculated. From the analysis of the T50 values, the influence of ethylcellulose appears clearly defined, observing a delay in release rate of cyromazine with respect to the basic lignin-PE formulation. In addition, the granules coated with ethylcellulose and the plasticizer lead the slowest release rate into water. The release of cyromazine into water is controlled by a diffusion mechanism. The thickness and permeability of the coating film are the most important factors that affect cyromazine release.

PH-sensitive film coatings: Towards a better understanding and facilitated optimization

The major aims of this study were: (i) to prepare and characterize polymeric film coatings with pH-dependent properties for oral administration; and (ii) to better understand the underlying mass transport mechanisms upon exposure to simulated gastric and intestinal fluids. Propylene glycol alginate (containing free carboxylic groups) was chosen as a pH-sensitive film former, which was blended with different amounts of ethylcellulose (being water-insoluble throughout the gastro-intestinal tract). The water uptake kinetics of thin free films in 0.1 M HCl and phosphate buffer pH 7.4 were monitored gravimetrically and quantitatively described using an appropriate analytical solution of Fick’s law of diffusion. Interestingly, the addition of only a low percentage (2.5–10%) of propylene glycol alginate to ethylcellulose significantly increased both, the rate and extent of the films’ water uptake, irrespective of the pH of the release medium. Importantly, diffusion was found to be the pre-dominant mass transport mechanism for all system compositions and types of release media. The apparent water diffusivity in the polymeric films could quantitatively be determined as a function of the polymer blend ratio. It significantly increased with increasing pH of the release medium, due to the presence of the free carboxylic groups in propylene glycol alginate. Also the dry mass loss of the polymer networks was much more pronounced at high compared to low pH. The differences in both water uptake as well as dry mass loss resulted in a clear pH-dependence of the drug release kinetics from coated pellets. Importantly, desired pH-sensitive release rates can easily be adjusted by varying the propylene glycol alginate content.