Ethyl cellulose

The aim of the present study is to develop and evaluate floating microspheres containing candesartan cilexetil in order to achieve extended release of drug and thereby to enhance the patient compliance. Floating microspheres were prepared by using solvent evaporation method. The microspheres were formulated using different polymers like ethyl cellulose, HPMC K4M and eudragit RSPO 100 in different concentrations and combinations. The prepared floating microspheres were characterized for their percentage yield (95.44 - 98.52%), drug entrapment efficiencies (71.52 - 97.87 %) and percentage buoyancy (93.45 - 98.66%). The FTIR and DSC studies revealed absence of interactions between drug and selected polymers. In vitro release studies were performed in 0.1 N HCl which showed a drug release of 97.62 % at 24 hour in case of formulation (F7). Fitting the in vitro drug release data to Korsmeyer equation indicated that Fickian diffusion is the mechanism of drug release.

The aim of present work is to study the release of diltiazem hydrochloride from tablets with ethyl cellulose (EC), eudragit RSPO and kollidon SR in different drug-to-polymer ratios were investigated with a view to develop twice-daily sustained release dosage form by polymeric dispersion (PD) technique. The polymeric dispersions containing ehtyl cellulose, eudragit RSPO or kollidon SR at drug-polymer ratios of 1:0.5, 1:1, 1:1.5, 1:2, with diltiazem hydrochloride were developed using solvent evaporation technique and co precipitation technique. The physical mixtures of drug and polymers were prepared by using simple mixing technique at the same ratio. The study of FTIR could not show significant interaction between diltiazem HCl and ethyl cellulose or kollidon SR or eudragit RSPO. Prepared tablets were evaluated for the release of diltiazem Hydrochloride over a period of 12 h in pH 7.4 phosphate buffer using US Pharmacopoeia type II dissolution apparatus. The in vitro drug release study revealed that the tablets prepared by dispersion technique have extended the release rate for 12 h whereas the tablets prepared by physical mixing technique at the same concentration have extended the release rate only up to 8 h. The in vitro release profile and the mathematical models indicate that release of diltiazem Hydrochloride can be effectively controlled from a tablet containing polymeric dispersion of eudragit RSPO.

Olmesartan medoxomil is an angiotensin II antagonist used as an antihypertensive drug which has poor oral bioavailability. Hence, an attempt was made to prepare and evaluate mucoadhesive buccal films containing Olmesartan medoxomil as model drug. Various mucoadhesive buccal films were prepared by employing HPMC alone, and in combination with Eudragit RL100, Carbapol 934, Ethyl cellulose were prepared by solvent casting method using ethanol , water and acetone as solvents, tween 80 as solubilising agent and glycerine as plasticizer. The prepared mucoadhesive buccal films were evaluated for their physic-chemical parameters such as thickness uniformity, weight uniformity, folding endurance, drug content , surface pH, swelling index, bioadhesion, percentage moisture loss and uptake, vapor transmission rate. The formulations exhibited good results. In – vitro drug release studies were conducted for OLM loaded films in phosphate buffer (pH 6.8) solution. The drug release was in the range of 67 to 90 % in 6hrs.. Stability studies were carried out with selected formulation. In- vivo release was evaluated in rabbits by patch test and it showed good correlation with the in-vitro release data. Drug release was found to be diffusion following zero order as per kinetic studies.

  The purpose of this research work was to develop and evaluate matrix-type transdermal therapeutic system containing Losartan potassium (LP) with different ratios of hydrophilic and hydrophobic polymeric combinations. Formulations were prepared by using solvent evaporation technique. Matrix type transdermal film of Losartan Potassium, antihypertensive drug were prepared using different polymers like Ethyl Cellulose, Hydroxy Propyl Methyl Cellulose and Eudragit RL100 in varied ratios. The present study aims to formulate and evaluate Transdermal film for sustained release of Losartan potassium. The results suggested no physicochemical incompatibility between the drug and the polymers. All formulations carried dimethyl sulfoxide as penetration enhancer and propylene glycol as plasticizer in chloroform and ethanol as solvent system. The diffusion studies were performed by using modified Franz diffusion cells. The formulation, F1 with combination of polymers (4:1) emerging to be ideal formulations for Losartan potassium. The developed transdermal films increase the efficacy of for the therapy of hypertension, chronic stable angina pectoris, and Prinzmetal's variant angina. Physicochemical parameters were characterized. The permeability study indicates that the drug is suitable for Transdermal drug delivery. The film were evaluated for various parameters like Thickness, Water-Vapour permeability, Tensile Strength, moisture loss, moisture uptake, film folding endurance , Drug Content, flatness, surface pH, swellability, % elongation, skin irritation and Diffusion studies. The films were further evaluated by DSC to ensure uniform distribution of the drug and compatibility of drug with polymer. The Optimized formulation containing HPMC: Eudragit RL100 (4:1), with enhancer DMSO showed 87.13% drug release after 24 hours.

  The aim of the present study was to prepare and characterize twice-daily sustained-release matrix tablets of Timolol maleate (TM) using different concentrations of hydrophilic Hydroxypropylmethylcellulose (HPMC K100M CR) alone and its combination with hydrophobic ethyl cellulose (EC). Formulations prepared by the wet granulation technique and were evaluated for the release of TM over a period of 12 hours using United States Pharmacopoeia (USP) type-II dissolution apparatus. Along with physical properties, the dynamics of water uptake and erosion degree of tablets were also studied. The in-vitro drug release study revealed that formulation F3 (40% wt/wt HPMC K100M) could extend the drug release up to 8 hours. The most successful formulation of the study, F5 (HPMC to EC, 1:1), extended the drug release up to 12 hours, exhibited satisfactory drug release in the initial hours, and the total release pattern was close to the theoretical release profile. The drug release from optimized formulation (F5) followed first-order kinetics via Non-Fickian (anomalous) diffusion. FTIR studies revealed that there was no interaction between the drug and excipients. In conclusion, the results indicated that the prepared sustained-release tablets of TM could perform therapeutically better than conventional tablets with improved efficacy and better patient compliance.   Key words: Timolol maleate; Matrix tablets; Sustained-release; Ethyl cellulose; Hydroxypropylmethylcellulose; In-vitro drug release.