Evaluation of the physicochemical properties of alkali-soluble polysaccharide from Poria and its application in diclofenac sodium sustained-release tablets / 药学学报

In this study, alkali-soluble polysaccharide was extracted from Poria residue, and the structure of alkali-soluble polysaccharide was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and differential scanning calorimetry (DSC). The physical morphology of alkali-soluble polysaccharide and ethyl cellulose (EC) was investigated by scanning electron microscopy (SEM), and the focus on angle of repose, bulk density, tapped density, Carr index, interparticle porosity, cohesion index, Hausner ratio, etc. The physical fingerprints were drawn, and the powder properties were evaluated by multivariate analysis. Diclofenac sodium extended-release tablets were prepared by direct compression method using alkali-soluble polysaccharide and EC as insoluble backbone materials to evaluate the basic properties of the extended-release tablets, investigate the in vitro drug release behavior and study the release mechanism. The results showed that alkali-soluble polysaccharide is a semi-crystalline polymer with smooth lamellar structure, and its stacking and compressibility are stronger than EC. The in vitro release experiments showed that the slow release performance of alkali-soluble polysaccharide is stronger than EC, and the release behavior of the prepared slow release tablets is in accordance with the Higuchi model. The pore structure is formed inside the tablets during the release process, and the release mode is pore diffusion release. The results of this study are of great significance for the development of new slow-release materials and the rational use of resources.

Preparation and Drug Release Mechanism of Time Controlled Explosive Pulsatile Tablets with Ethylcellulose Coating

Background The time rhythm of human body is associated with the occurrence and development of manydiseases, and it also affects the efficacy and pharmacokinetic characteristics of the corresponding therapeuticdrugs. Therefore, the chronopharmacological drug delivery system has potential applications. Aim In this work, it is proposed to develop a kind of pulsatile release tablet of simple structure and preparingprocess, thus to provide an alternative drug delivery system for therapeutic agents used in treatment of diseasesof typical onset biorhythm at period inconvenient to take drug.Methods Metoprolol tartrate (MT), a drug widely used clinically to treat cardiovascular diseases was selected asa model drug for developing pulsatile tablets of time-controlled explosive system (TES). The MT pulsatile tabletswere ethyl cellulose (EC) coating tablets produced by pan coating process, and the core tablets were preparedby direct compression. The formulation and process was optimized by single factor test and orthogonal design.Also, the pulsatile release mechanism of the tablets was discussed through investigating the water absorptionand swelling capacity of tablets as well as the mechanical properties of EC free film.Results A kind of pulsatile tablets of MT were developed with a drug release lag time around 7 h and a fastrelease of drug after lag time. When the swelling force of core tablet caused by water uptake was high enoughover the tensile strength of EC coating film, the MT pulsatile tablets demonstrated a shell-type exploding rupturedue to the great rigidity and weak flexibility of EC film, and then a fast pulsatile release of drug was observed.Both the swelling capacity of core tablet and the thickness of coating film together controlled the lag time of drugrelease. The lag time showed a good linear relationship with the thickness of coating film (r = 0.9984, P < 0.01).The sort and amount of fillers and disintegrants dominated the release behaviour after lag time.Conclusion The developed MT pulsatile tablets can exert a timely release of drug before peak onset period ofhypertension and angina pectoris early in the morning after drug taking around 22:00 P.M the night before. Thegood linear relationship between lag time and coating thickness enabled the pulsatile tablets to be used fordelivery of other therapeutic agents of similar chronotherapy demand by adjusting the coating thickness toachieve the appropriate lag time of drug release to match the different high attack rhythm of the exact diseases.

Fabrication of potential gastroretentive microspheres of itraconazole for stomach-specific delivery: Statistical optimization and in vitro evaluation

The premise of the study was to develop and optimize multiple unit gastroretentive microspheres of itraconazoleto prolong its localization in the stomach and analyzed using response surface methodology. The emulsion solventdiffusion evaporation method was used to prepare hollow microsphere of ethyl cellulose and Eudragit RS100 as lowdensity shell-forming polymers. The experimental design matrix was prepared using a central composite design tostudy the effect of various process parameters over response variables. The optimized microspheres showed a particlesize of 285.1µm, drug entrapment efficiency of 86.8%, buoyancy of 51.1%, and cumulative drug release of 77.80%.The experimental responses were in good harmony with the predicted values. The compatibility between drug andexcipients was determined by Fourier-transform infrared and differential scanning calorimetry analysis. The resultssignify that gastroretentive hollow microspheres are a promising vehicle to extend the retention time of itraconazolein the upper GI tract, and it can be floated in an acidic medium for a prolonged period.

Effect Of Different Formulation Variables On Release Characteristics Of Gastro-Floating Microspheres Of Ethyl Cellulose/Carbopol 934p Encapsulating Sorafenib

Objective: The aim of this study is to prepare floating hollow microspheres encapsulating Sorafenib (SFN) to enhance its oral bioavailability.  Methods: Gastro-floating hollow adhesive microspheres containing SFN were produced by using an emulsion solvent evaporation technique with ether and ethanol as solvents. Ethyl cellulose and carbopol 934P were used as the encapsulating carriers. The effects of formulation parameters like, solvent volume ratio, and drug to polymer ratio (D: P ratio), encapsulation efficiency percentage EE%, floating percentage, and release of SFN after 12 h (Rel12) were investigated and analyzed using a (32) full factorial design. Results: The floating percentage of the microspheres was found to be 76.5%. The in vitro drug release from these hollow microspheres followed the Higuchi model equation. The in vivo results showed that approximately 1.96-fold improvement in the relative bioavailability of the microspheres compared with that of the commercial tablet.  Conclusion: The results demonstrate that the hollow microspheres with good gastro-floating ability are a promising delivery system to enhance SFN bioavailability.

Formulation And Characterization Of Ondansetron Hydrochloride Matrix Tablets For Sustained Drug Delivery

The objective of proposed work was to develop Ondansetron Hydrochloride (OND HCl) sustained release matrix tablets for the better treatment of vomiting for extended period of time. Sustained release matrix tablet is the drug delivery system that is designed to achieve a prolonged therapeutic effect by continuously releasing medication over an extended period of time after administration of single dose. The matrix tablets of OND HCl were prepared by direct compression method using varying ratio of hydroxy propyl methyl cellulose (HPMC) and ethyl cellulose. The bends of tablets were evaluated for bulk and tapped density, % compressibility index and angle of repose and powder of all formulations blend exhibited that low interparticle friction and excellent flow characteristics. The prepared matrix tablets were then assessed for different physical tests like consistency of weight, thickness, hardness, friability, drug content and in vitro drug release. Each batch of the OND HCl matrix tablets were of good quality as to hardness, thickness, friability and % medicament content. The in vitro drug release study was done for 2 hours by utilizing paddle technique in 0.1N HCl (pH 1.2) as dissolution media and 6 hours using phosphate buffer (pH 6.8) as dissolution media. The drug release study showed that all formulation FMT-1, FMT-2, FMT-3, FMT-4, FMT-5 and FMT-6 were provide the drug release on sustained manner up to 8 hrs. Amongst the developed matrix tablets formulations, FMT-2 containing ethyl cellulose (100 mg) was optimized as best because FMT-2 show highest drug release profile and promoting the sustained release of drug, which could potentially improve the patient compliance.

Formulation Design And Optimization Of Floating Matrix Tablets Of Ciprofloxacin Hcl By Using Hpmc And Ethyl Cellulose With Experimental Design

The oral floating matrix tablets of Ciprofloxacin Hydrochloride were formulated by Experimental design by using HPMC K100M and Ethyl Cellulose as the retardant polymers each with three different levels with an approach to increase gastric residence and thereby improve drug bioavailability. From FTIR results it was confirmed that there is no chemical interaction between the drug with the excipients used in tablet formulations. Also, there was no shift in the endotherm of in the drug- excipients mixtures indicating compatibility of drug with all the excipients. All the tablets were prepared by effervescent approach in which Sodium bicarbonate was added as a gas generating agent. Floating Matrix tablets were prepared by direct compression method and prepared tablets were evaluated for weight variation, percentage friability, hardness and drug content studies. All the formulations showed compliance with pharmacopeia standards (I.P. 1996). Floating lag times of all the formulations were within 1 minute and Total floating time of all the formulations were more than 12 hours. In vitro release studies revealed that the release rate decreased with increase polymer proportion of retarding polymers. The formulation CHE9 sustained release of drug for 12 hours with 21% release of drug after 1 hour and more than 97% at the end of 12 hours. From the Kinetic model it was found that the optimized formulation CHE9 showed linearity in case of Zero order (R2: 0.938) and Higuchi model (R2: 0.954). By fitting data to Korsmeyer-Peppas model and ‘n’ value lying above 0.5 indicating non Fickian release.

Formulation development and evaluation of colon targeted delayed release methotrexate pellets for the treatment of colonic carcinoma

Colonic carcinoma is one of the most common internal malignancies and is the second leading cause of deaths in United States. Methotrexate (MTX) is a drug of choice in the treatment of colon cancer. The aim of the present research work was to develop and characterize colon targeted pellets of MTX for treatment of colonic carcinoma. The product and process parameters were optimized by screening methods. Pellets were prepared by extrusion spheronization using microcrystalline cellulose (MCC) as spheronizing aid and ethyl cellulose (EC) as release retardant in different ratio. Based on the physical appearance, sphericity and % in vitro drug release, batch P17 containing EC: MCC (3:7) was optimized for core pellets. The site specificity was obtained by screening the coating polymers and by coating the core pellets with EudragitS100. The 32 full factorial design was applied in which airflow rate (X1) and coating time (X2) were the independent parameters and physical appearance (Y1) and time taken for 100% drug release (Y2) were selected as the dependent variables. From the results obtained, 6min of coating time and 60cm3/min airflow rate was optimized. The batch B5 showed appropriate physical appearance and % in vitro drug release upto 17hr indicating sustained release property. The ex-vivo studies performed on rat colon indicated a significant relation with the in vitro drug release. The drug release followed Higuchi's model indicating the diffusion pattern of drug release from the matrix of pellets. Thus, the coated pellets can be a good candidate for site specific delivery of MTX to colon by decreasing the gastric irritation and thus to improve bioavailability.

In vitro evaluation of sustained released matrix tablets containing ibuprofen: a model poorly water-soluble drug

ABSTRACT A matrix system was developed that releases ibuprofen (IB) over a 12-hour period and the influence of the polymer type and concentration on the release rate of the drug was evaluated. Tablets containing different concentrations of Carbopol (CP), hydroxypropyl methylcellulose (HPMC), or ethyl cellulose (EC) were prepared using direct compression and the drug content, content uniformity, hardness, friability, dissolution performance, and in vitro release kinetics were examined. Formulated tablets were found to be within acceptable limits for physical and chemical parameters. The release kinetics of the Carbopol(r)971P 8% formulation showed the best linearity (r 2 =0.977) in fitting zero-order kinetics, suggesting the release rate was time independent. The drug release from tablets containing 8% CP was extended over approximately 18 hours and the release kinetics were nearly linear, suggesting that this system has the potential to maintain constant plasma drug concentrations over 12 hours, which could reduce the frequency of administration and the occurrence of adverse effects associated with repeated administration of conventional IB tablets.

Formulation and Evaluation of Nanoparticles as Sustained Release Topical Formulation Containing Non-Steroidal Anti -Inflammatory Drug.

The objective of this work is to prepare flurbiprofen nanoparticles, and then incorporated into the freshly prepared gels for transdermal delivery, providing controlled release of the drug, reducing the oral side effects of the drug and for enhancing stability. Flurbiprofen is a non-steroidal anti-inflammatory drug used to treat gout osteoarthritis, rheumatoid arthritis, and sunburn. In this study Flurbiprofen nanoparticles are prepared by nanoprecipitation method. A total of 8 batches are prepared by using polymers such as ethyl cellulose, Eudragit L100 and are evaluated for various parameters. Drug-excipients compatibility was performed by FTIR study. Optimized batch of nanoparticles F3 was further formulated as gel for topical delivery. A total of 4 batches of gel were prepared using different concentrations of carbopol 934. Prepared gel formulations are evaluated for physical parameters and in vitro drug permeation study. The in-vitro release rate of gel preparations was evaluated by diffusion cell method using cellophane membrane with phosphate buffer pH Z4 as the receptor medium. F3-G1 showed highest in-vitro release rate and superior physicochemical properties. These formulations were evaluated for ex-vivo permeation study through chicken skin using Franz diffusion cell. The drug release data of optimized batch were fitted into different kinetic models which show that the drug release from gel formulations follow zero order release. The overall studies concluded that the F3-G1 Flurbiprofen nanoparticle gel can be effectively used for the treatment of chronic conditions of rheumatoid arthritis, osteoarthritis.

Treatment of Helicobacter pylori infection mice with Anti-H. pylori rFlaA IgY-sucralfate EC microcapsules / 中国药学杂志

OBJECTIVE: To investigate the efficacy of Anti-H. pylori rFlaA IgY-sucralfate ethyl cellulose(EC) microcapsules on Helicocacter pylori infection in mice. METHODS: After dealing with sucralfate, the rFlaA IgY microcapsules were prepared with EC by organic solvent evaporation method. The protective effect of sucralfate at different concentrations of pepsin in different pH on the rFlaA IgY activity was also evaluated. Treating the mice with the microcapsules by oral at various dosages (0.8, 1.6, 3.2 and 6.4 mg · g-1 · d -1), the anti- H. pylori serum of the mice and the urease of the gastric mucosa were detected to evaluate the clearance rate of H. pylori by ELISA and rapid urease test. RESULTS: The results showed that under simulated gastric juice with common pepsin concentration (0.02 mg · mL-1), the relative activity of the IgY treated with 40% sucralfate can maintain 82.14% for 8 h at pH 3.0 and 63.28% at pH 2.0, it can only keep 21.52% at pH 1.0. While under the simulated gastric juice with high pepsin concentration (0.04 mg · mL-1), the relative activity of the IgY can maintain 77.87% with 40% sucralfate at pH 3.0, 57.76% at pH 2.0 and 22.79% at pH 1.0. The entrapment efficiency of the EC microcapsules was 83.79%. The release rate of the EC microcapsules was 95.92% in 5 h. After treatment with rFlaA IgY EC microcapsules, the levels of anti-H. pylori antibody were significantly decreased in each group. The clearance rate of H. pylori at dosage of 3.2 mg · g-1 · d-1 was 80%, the rFlaA IgY at dosage of 6.4 mg · g-1 · d-1 can completely clear the H. pylori in mice gastric mucosa. CONCLUSION: The 40% sucralfate can protect IgY in the simulated gastric juice. The rFlaA IgY EC microcapsules have high entrapment efficiency and sustained-release effect in vitro as well as good clearance effect of H. pylori infection by oral administration.

Design and optimization of self-microemulsifying drug delivery system (SMEDDS) of felodipine for chronotherapeutic application

The objective of this research work was to design, develop and optimize the self micro-emulsifying drug delivery system (SMEDDS) of Felodipine (FL) filled in hard gelatine capsule coated with polymer in order to achieve rapid drug release after a desired time lag in the management of hypertension. Microemulsion is composed of a FL, Lauroglycol FCC, Transcutol P and Cremophor EL. The optimum surfactant to co-surfactant ratio was found to be 2:1. The resultant microemulsions have a particle size in the range of 65-85 nm and zeta potential value of -13.71 mV. FL release was adequately adjusted by using pH independent polymer i.e. ethyl cellulose along with dibutyl phthalate as plasticizer. Influence of formulation variables like viscosity of polymer, type of plasticizer and percent coating weight gain was investigated to characterize the time lag. The developed formulation of FL SMEDDS capsules coated with ethyl cellulose showed time lag of 5-7 h which is desirable for chronotherapeutic application.

O objetivo desse trabalho de pesquisa foi planejar, desenvolver e otimizar sistema de liberação de fármaco auto-microemulsificante(SMEDDS) de felodipino (FL) em cápsulas de gelatina dura revestidas com polímero, a fim de obter liberação rápida após tempo desejado no manejo da hipertensão. A microemulsão é composta de FL, lauroglilcol FCC, Transcutol P e Cremophor EL. A proporção ótima de tensoativo e de co-tensoativo foi de 2:1. As microemulsões resultantes têm tamanho de partícula na faixa de 65-85 nm com potencial zeta de -13,71 mV. A liberação de FL foi ajustada adequadamente, utilizando-se polímero independente de pH, como etilcelulose com ftalato de dibutila como plastificante. A influência das variáveis da formulação, como viscosidade do polímero, tipo de plastificante e ganho percentual de peso do revestimento foi investigada para caracterizar o intervalo de tempo de liberação. A formulação de cápsulas de FL SMEDDS revestidas com etilcelulose mostrou intervalo de tempo de liberação de 5 a 7 horas, o que é desejável para uma aplicação cronoterapêutica.

Preparation of sustained release ethyl cellulose nanofibers by coaxial electrospinning with ethanol as sheath fluid / 中国药学杂志

OBJECTIVE: To investigate the preparation of sustained release drug-loaded nanofibers by using a modified coaxial electrospinning process, in which only solvent is exploited as sheath fluid. METHODS: Ethanol was used as sheath fluid and ethyl cellulose (EC) and ferulic acid (FA) were taken as filament-forming matrix and active pharmaceutical ingredient, respectively. RESULTS: Drug-loaded EC nanofibers were smoothly and continuously generated without any clogging through the coaxial process. Field-emission scanning electron microscopic observations demonstrated that the nanofibers' diameters could be manipulated through adjusting the flow rate of sheath fluid. The composite nanofibers were in essential a molecular solid dispersion of EC and FA based on the hydrogen bonding between them, as verified by XRD and FTIR results. In vitro dissolution tests showed that FA in the nanofibers had a fine sustained release profile via a typical Fickian diffusion mechanism. CONCLUSION: The modified coaxial electrospinning with solvent as sheath fluid can be a useful tool for developing novel sustained release drug delivery systems.

Design and evaluation of a gastroretentive drug delivery system for metformin HCl using synthetic and semi-synthetic polymers / Diseño y evaluación de un sistema gastro-retentivo de administración de metformina HCl, utilizando polímeros sintéticos y semisintéticos

The aim of the present research was to prepare and evaluate a gastroretentive drug delivery system for metformin HCl, using synthetic and semi-synthetic polymers. The floating approach was applied for preparing gastroretentive tablets (GRT) and these tablets were manufactured by the direct compression method. The drug delivery system comprises of synthetic and semi-synthetic polymers such as polyethylene oxide and Carboxymethyl ethyl cellulose (CMEC) as release-retarding polymers. GRT were evaluated for physico-chemical properties like weight variation, hardness, assay friability, in vitro floating behaviour, swelling studies, in vitro dissolution studies and rate order kinetics. Based upon the drug release and floating properties, two formulations (MP04 & MC03) were selected as optimized formulations. The optimized formulations MP04 and MC03 followed zero order rate kinetics, with non-Fickian diffusion and first order rate kinetics with erosion mechanism, respectively. The optimized formulation was characterised with FTIR studies and it was observed that there was no interaction between the drug and polymers.

El objetivo del presente trabajo consistió en preparar y evaluar un sistema de administración gastro-retentivo de metformina HCl, utilizando polímeros sintéticos y semisintéticos. Se aplicó el método de flotación para la elaboración de los comprimidos de retención gástrica (CRG) y éstos se prepararon mediante el método de compresión directa. El sistema de suministro del fármaco estaba constituido por polímeros sintéticos y semisintéticos, tales como el óxido de polietileno y la carboximetil etil celulosa, como agentes retardadores de la liberación del fármaco. Se evaluaron las propiedades físico-químicas de los CRG, tales como: variación de peso, dureza, friabilidad, comportamiento flotante in vitro, capacidad de inflación, estudios de disolución in vitro y su tasa de orden cinético. Se seleccionaron dos fórmulas (MP04 y MC03), sobre la base de la liberación del fármaco y las propiedades de flotabilidad, como fórmulas óptimas. Estas fórmulas MP04 y MC03 optimizadas siguieron cinéticas de velocidad de orden cero, con difusión no-Fickian y tasa cinética de primer orden con mecanismo de erosión, respectivamente. Las fórmulas óptimas se caracterizaron con estudios FTIR y se observó que no hubo interacción entre el fármaco y los polímeros.

Preparation and Evaluation of Novel Expandable Drug Delivery System.

Aims: The purpose of this research is to develop a novel expandable gastroretentive dosage form (GRDF), based on unfolding mechanism. It consists of a drug loaded bilayer polymeric film, folded into a hard gelatin capsule. Gastric retention is achieved due to unfolding of the dosage form within 15-20 min. Furosemide is selected as the drug candidate for this work. Due to its narrow absorption window, Furosemide has to be administered to the upper parts of the intestine in order to maintain sustained therapeutic levels. This may be achieved by a GRDF. Methodology: Films were prepared by solvent-casting technique using Ethyl cellulose, HPMC E15 and Eudragit RLPO as polymers and dibutyl phthalate as the plasticizer in both layers. The film with zigzag folding in the capsule was shown to unfold in the gastric juice and provide drug release up to 12 h in the acidic medium. The films were evaluated for weight & thickness variation, mechanical properties, in vitro drug release and unfolding behavior based on the mechanical shape memory of polymers. Absence of drug polymer interaction and uniform drug dispersion in the polymeric layers was revealed by DSC, XRD studies and SEM. The GRDF location in the gastrointestinal tract was determined by X-ray studies. Results: X-ray studies revealed that the GRDF is retained in the stomach up to 6± 0.5 h in fasting condition and 8 h in fed state. Conclusion: The polymers used in the development of GRDFs were safe and proper combination of these polymers will yield a novel expandable GRDF with good in vitro drug release in acidic media, mechanical properties, and unfolding behaviour. These outcomes demonstrate that the GRDF may be used to improve furosemide therapy and can be applied to extend the absorption of other narrow absorption window drugs that require continuous input.

Optimization of Gabapentin Release and Targeting Absorption, Through Incorporation into Alginate Beads.

Aims: 1) To study the effect of some formulation variables on drug load, encapsulation efficiency, swelling ratio, mucoadhesion and drug release. 2) Optimize the mucoadhesion capabilities for targeting drug absorption and release-controlling capabilities of alginate beads. Methodology: Alginate beads were prepared by dripping sodium alginate gel into calcium chloride solution and then dried overnight at ambient temperature. The effects of alginate concentration, cross linker concentration, cross linking time, volume of cross linking solution and drug/polymer ratio on drug load, encapsulation efficiency, swelling ratio, mucoadhesion and drug release were investigated. Formulae containing sodium lauryl sulfate (SLS), gabapentin-ethylcellulose solid dispersion, mixture of free drug and solid dispersion were prepared for modifying the drug release rate. Results: Mucoadhesion of alginate beads was shown to be decreased upon adding SLS (30% after 8 hrs). Drug release was so fast (92.46% after 2 hrs). The incorporation of solid dispersion has led to well accepted mucoadhesion (74.44% after 8 hrs) as well as release properties (93.35% after 10 hrs) Beads containing mixtures of drug and ethylcellulose-drug solid dispersion showed acceptable mucoadhesion (74.44% after 8 hrs) and control of gabapentin release (93.35% after 10 hrs). Statistical analysis of variance between groups was performed using the one-way layout ANOVA with duplication. Significant differences in mean values were evaluated by Student's unpaired t test (P < 0.05). Conclusion: A finally optimized formula was suggested by incorporating a combination of solid dispersion and free gabapentin in alginate system to achieve burst release of gabapentin and hence fast effect (33.417% was released during the first 30 minutes in fasting-simulated conditions) and controlled release (91.217% after 6 hrs).

In Vitro and In Vivo Evaluation of Combined Time and pH- Dependent Oral Colonic Targeted Prednisolone Microspheres.

Aims: to enhance the anti-inflammatory effect as well as oral absorption of prednisolone (PR), through formulation of colonic targeted microspheres prepared from a blend of time and pH- dependent polymers and loaded with PR. Study Design: In Vitro and In Vivo Evaluation of Combined Time and pH- Dependent Oral Colonic Targeted Prednisolone Microspheres. Place and Duration of Study: Department of Pharmaceutics and Industrial Pharmacy, Helwan University, Cairo, Egypt between June 2011 and October 2012. Methodology: Microspheres were prepared by solvent evaporation method using different ethyl cellulose (EC) and Eudragit® S-100 (ES100) ratios with 0.5 and 1% w/v span® 80 as emulsifier. The microspheres were evaluated for surface morphology, particle size, drug encapsulation efficiency % and in vitro drug release at pH 1.2 and 7.4. The antiinflammatory activity of selected formula was compared to that of conventional PR tablets. Results: A decrease in drug entrapment efficiency % was obtained with increasing both polymers and surfactant concentrations. Based on drug release results, the formula of 1: 1: 0.16 w/w/w, EC: ES100: PR ratio with 1% w/v span® 80 was selected for further histopathological evaluation of the anti-inflammatory activity in colitis induced-rats. Histopathological study showed undefined tissue necrosis after treatment with the selected microspheres; however, diffused necrosis was observed in rats treated with the commercial tablets. In vivo absorption study showed that values of Cmax and AUC0-24 of both formulations were insignificantly different. However, the occurrence of Cmax of microspheres was significantly delayed in comparison to free drug (9.17 to 2.67hr) (P<.001). Conclusion: This study has supplied us with brightening results concerning the therapeutic efficacy of a blend of time and pH- dependent polymers colonic targeted microspheres.

Development and in vitro characterization of esomeprazole floating gastro retentive microspheres.

The present study was to prepare and evaluate the floating microspheres of Esomeprazole magnesium trihydrate as a model drug for prolongation of the gastric retention time for oral delivery. EMT is a proton pump inhibitor which acts by irreversibly blocking the (H+K+)-ATPase enzyme system of the gastric parietal cell. Its half life is 1-1.5 hrs. EMT poor absorption may be because of degradation in gastric acid which can be prevented by incorporation of sodium bi carbonate which is a systemic antacid and act as buffer. The EMT floating microspheres were prepared by double emulsion solvent diffusion method by using Ethyl cellulose and different grades of HPMC like K4M, K15M, using Dichloromethane and alcohol solvent systems. EMT Floating microspheres were evaluated for micromeritic properties, particle size, % yield, In-Vitro buoyancy, incorporation efficiency and drug release. The prepared microspheres were found to be spherical and free flowing and remain buoyant for more than 10 hrs and the particle sizes of microspheres were found to be in the range of 67.24±4.57 μm to 106.35±5.67μm. Incorporation efficiency was found in the range of 54.75±3.51to 83.97±2.54. In-vitro release profile of optimized formulations follows first order non-Fickian (Anomalous) release indicates diffusion and dissolution controlled release. FT-IR and DSC studies revealed the absence of any chemical interaction between drug and polymers used. During the stability period selected microspheres were found to be stable with respect to Entrapment efficiency and drug release characteristics.

Formulation and evaluation of colon specific microbial degradable matrix tablet using sterculia gum as carrier.

Current study is to develop the colon targeted matrix tablet using the natural polysaccharide sterculia gum as carrier and model drug ciprofloxacin HCl. The matrix tablets were prepared by wet granulation technology using the various proportions of sterculia gum with carbopol 934 P, sterculia gum and ethyl cellulose polymer blends. Gra-nules of all formulations were evaluated for rheological, post compressional properties and in vitro dissolution study in different pH buffers of pH 1.2 , pH 7.4 , pH 6.8 (saline phosphate buffer) without and with 4% rat cecal content in order to mimic GIT condition . Formulation SGC2 to SGC4 and SGE7 to SGE9 has released 13.6% to 38.9% in the initial 5h and released more amount of drug in stomach and small intestine than colon. Formulation SGC5 containing 45% of sterculia gum and 25% carbopol 934 p and Formulation SGE10 containing 45% of sterculia gum and 25% ethyl cellulose has released minimum 10.91 % to 13.04 % in the initial 5h and sustained the drug release up to 24 h and at the end of study released 75% to 79.99%. Formulations with 4% rat cecal content at the end of 24 h study drug released is 90.44% to 95.33% indicating higher amount of drug release is due to enzymatic break down of sterculia gum in the matrix tablet. Hence the above results conclude that the formulation SGC5 and SGE10 are potential in targeting the drug to colon to treat irritable bowel disease.

Formulation and evaluation of telmisartan microspheres by emulsion solvent evaporation technique.

Microspheres are multi-component system provide constant and prolonged drug release. Furthermore their floating abilities increase gastric residence time. These properties reduce the gastrointestinal toxic effects and dosing frequency and thereby improve the patient compliance. The present study aimed to formulate and evaluate telmisartan microspheres. Emulsion solvent evaporation (ESE) technique was employed for microsphere preparation using different ratios of ethyl cellulose polymer and drug. Prepared microspheres were evaluated for drug entrapment efficiency, micromeritic characters, floating behaviour and in vitro drug release. This revealed polymer drug ratio has influence on drug release.

Preparation of glycolic acid ethyl cellulose microspheres / 第二军医大学学报

Objective To prepare glycolic acid ethyl cellulose microspheres (GAECM) for hepatic artery embolization treatment and to investigate their in vitro release property. Methods GAECM was prepared using ethyl cellulose as a carrier, adding glycolic acid, by a double emulsion method. The appearance, particle size, drug loading, and encapsulation efficiency were used as indices to assess the roundness, smoothness, size uniformity, and drug contents of the microspheres. The in vitro release characteristics of the microspheres were determined by constant temperature oscillation dialysis. Results and conclusion The prepared GAECM has a smooth round appearance, with a mean diameter of (233.38±1. 62) μm, a mean drug loading of 114.32 μg/mg, an encapsulation efficiency of 78. 61%, and a release period of 72 h. The microspheres can meet the requirements of further animal experiments, which provides important reference for using chemical corrosion in drugs used for hepatic arterial embolization studies.