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THE use of hydrofoils for a wide variety of purposes such as propeller blades on boats, as sailboat keels, ship rudders, submarine and torpedo fins, lifting surfaces of hydrofoil boats, and shroud ring stabilizers for missiles, has prompted efforts to increase the lift-to-drag ratio by various means. The favourable drag reducing effect of polymers, particularly for flows in pipes1, suggests
A mucoadhesive drug delivery system for local delivery of metronidazole through vaginal route was formulated. Films were prepared by solvent evaporation method using various compositions of Carbopol, hydroxypropylmethylcellulose, chitosan, Polyox and propylene glycol. The films were evaluated for their weight, thickness, surface pH, folding endurance, mechanical, drug content uniformity, in vitro drug release, swelling, gelling and mucoadhesion property. All the films possess satisfactory film characteristics. Films made of Polyox found to possess acceptable, physicochemical, mechanical, gelling and mucoadhesion property for delivery of metronidazole.
Tests were made with Polyox, Guar Gum and tap water for different flow conditions. The results with tap water for parallel walls showed fair agreement with the results of other investigators. The most significant results were those of overall sound-pressu...
The radioinduced grafting of acrylonitrile onto polyethylene oxide in ; both in situ and postirradiation cases was investigated. It was found that ; gamma -irradiation of polyethylene oxide (POLYOX) swollen with acrylonitrile both ; in the presence and in the absence of benzene resulted in insoluble products ; which could not be fractionated. Based on infrared analysis, solubility ; characteristics,
The wake region of the flow of dilute polymer solution about a circular cylinder was studied. Polyox WSR-301 at a concentration of 25 WPPM was dissolved in tap water. The investigation was performed in the drag transition flow regime. Turbulence intensity...
The influence upon the basic viscous flow about two axisymmetric bodies of (i) freestream turbulence level and (ii) the injection of small amounts of a drag-reducing polymer (Polyox WSR 301) into the test model boundary layer was investigated by the schli...
Staphylococcus aureus and Strepto- coccus agalactiae growth responses to metabolites of Corynebacterium boris cultured in media containing polyox- yethylenesorbita n monolaurate, mono- oleate, or trioleate and milk were de- termined. Filter sterilized metabolites of 48-h C. boris cultures in synthetic media were added to cultures of Staph. aureus and Strep. agalactiae. Staphylococcus aureus and Strep. agalactiae were in- oculated into
Context: Simvastatin is a hypolipidemic drug used in atherosclerosis. It has short elimination half life (2-3 hours) and narrow absorption window. It is mainly absorbed from stomach. Objective: The objective of this research was to develop gastroretentive floating tablets of Simvastatin using combination of release retardant polymers like Polyox WSR 205, Polyox WSR N12K and HPMC K4M. Material and methods: 3(2) full Factorial design was applied to design the experiments and tablets were prepared by direct compression. Prepared floating tablets were evaluated for hardness, floating time, friability, % drug content, swelling index, in-vitro drug release study and mean gastric retention period by invivo X-ray study. Statistical analysis was done using design expert software and model fitting was carried out using PCP DISSO. Design expert software was validated by comparing predicted results with observed results. Results and conclusion: Statistical analysis data revealed that tablets from formulation batch D3 (containing HPMC K4M 10% and POLYOX WSR 205 35%) and formulation batch E2 (HPMC K4M 10% and Polyox WSR N12K 25%) were promising system exhibiting excellent floating properties and drug release pattern. Stability studies revealed that all formulations were physically and chemically stable. In-vivo X-ray imaging of formula D3 and formula E2 shows mean gastric retention time of 6 ± 0.5 hours. PMID:23607639
Hydrophilic matrix tablets containing polyethylene oxides as the retarding polymer have been successfully employed in the controlled release of drugs. To evaluate the relative influence of drug diffusion and polymer erosion mechanisms in the drug delivery process, we studied the hydration behaviour of matrix tablets containing a water-soluble drug and PEOs of two different molecular weights: Polyox WSRN 1105 (Mw=0.9×106)
L. Maggi; L. Segale; M. L. Torre; E. Ochoa Machiste; U. Conte
The water-soluble, viscoelastic resin Polyox WSR 301), a poly(ethylene oxide) of high molecular weight (approximately 4 million) is introduces as a new slowing agent for protozoa. Generally, as the kinetic viscosity of the resin increased from 0.25% to 1% (w/v), the swimming velocity of Euglena gracilis, Didnium nasutum, Paramecium aurelia, Blepharisma undulans, and Prorodon platyodon decreased. The 1.0% solution had the highest viscosity and decreased velocity more effectively than 1.0% methyl cellulose and Protoslo solutions. The Polyox solutions differed from those of methyl cellulose and Protoslo by having, in addition to viscous drag, an elastic recoil that pulled the protozoa backwards when their swimming efforts stopped. The toxicity of these slowing agents was determined using 10 P. aurelia/test slide preparation. Paramecium numbers decreased in 1.0% methyl cellulose and Protoslo to nearly zero by 24 hr; in Polyox, not only were most these ciliates alive after 24 hr, but many survived for 96 hr and divisions occurred in 0.25% and 0.50% solutions. PMID:21290
Lamotrigine is a BCS class II drug with pH dependent solubility. The bilayered gastric mucoadhesive tablets of lamotrigine were designed such that the drug and controlled release polymers were incorporated in the upper layer and the lower layer had the mucoadhesive polymers. The major ingredients selected for the upper layer were the drug and control release polymer (either HPMC K15M or polyox) while the lower MA layer predominantly comprised of Carbopol 974P. A 23 full factorial design was constructed for this study and the tablets were optimized for parameters like tablet size, shape, ex vivo mucoadhesive properties and unidirectional drug release. Oval tablets with an average size of 14 mm diameter were set optimum. Maximum mucoadhesive bond strength of 79.3 ± 0.91 * 103 dyn/cm2 was achieved with carbopol when used in combination with a synergistic resin polymer. All the tested formulations presented a mucoadhesion time of greater than 12 h. The incorporation of methacrylic polymers in the lower layer ensured unidirectional drug release from the bilayered tablets. The unidirectional drug release was confirmed after comparing the dissolution results of paddle method with those of a modified basket method. Model independent similarity and dissimilarity factor methods were used for the comparison of dissolution results. Controlled drug release profiles with zero order kinetics were obtained with polyox and HPMC K15M which reported t90% at 6th and 12th hours, respectively. The “n” value with polyox was 0.992 and that with HPMC K15M was 0.946 indicating an approximate case II transport. These two formulations showed the potential for oral administration of lamotrigine as bilayered gastric mucoadhesive tablets by yielding highest similarity factor values, 96.06 and 92.47, respectively, between the paddle and modified basket method dissolution release profiles apart from reporting the best tablet physical properties and maximum mucoadhesive strength.
Mohana Raghava Srivalli, K.; Lakshmi, P.K.; Balasubramaniam, J.
Friction and heat transfer data for three concentrations (100, 300, and 500 ppm) of a water-soluble polymer (Polyox WSR-301) and two pipe diameters (1.11 and 1.88 cm I.D.) are presented. The friction data are correlated by a single curve using the correlation method developed by Astarita et al. for drag reduction. This method is extended to the case of heat transfer reduction. Using the proposed method, all the heat transfer data also correlates by a single curve.
In the present investigation an attempt has been made to increase therapeutic efficacy, reduced frequency of administration and improved patient compliance by developing controlled release matrix tablets of verapamil hydrochloride. Verapamil hydrochloride was formulated as oral controlled release matrix tablets by using the polyethylene oxides (Polyox WSR 303). The aim of this study was to investigate the influence of polymer level and type of fillers namely lactose (soluble filler), swellable filler (starch 1500), microcrystalline cellulose and dibasic calcium phosphate (insoluble fillers) on the release rate and mechanism of release for verapamil hydrochloride from matrix tablets prepared by direct compression process. Higher polymeric content in the matrix decreased the release rate of drug. On the other hand, replacement of lactose with anhydrous dibasic calcium phosphate and microcrystalline cellulose has significantly retarded the release rate of verapamil hydrochloride. Biopharmaceutical evaluation of satisfactory formulations were also carried out on New Zealand rabbits and parameters such as maximum plasma concentration, time to reach peak plasma concentration, area under the plasma concentration time curve(0-t) and area under first moment curve(0-t) were determined. In vivo pharmacokinetic study proves that the verapamil hydrochloride from matrix tablets showed prolonged release and were be able to sustain the therapeutic effect up to 24 h.
Carbamazepine indicated for the control of epilepsy, undergoes extensive hepatic first-pass metabolism after oral administration. A vaginal dosage form of carbamazepine is not commercially available. Conventional suppository having poor retention in the vaginal tract, as they are removed in a short time by the tract's self-cleansing action, having poor patient compliance. To overcome such problems, delivery system with mucoadhesive polymers polyox WSR N-60K and Ucarflock 302 that prolong drug permanence on the vaginal mucosa were developed. In the present study the suitability of gelucires to formulate vaginal pesseries was investigated. The possible modification of carbamazepine release kinetics by using gelucires blends and hydrophilic additives in the pesseries was evaluated. It was observed that among gelucire grades melting point higher than 37 degrees C, the release rate proved to be highly dependant on HLB value and matrix composition. In most of the formulations carbamazepine release occurred by disintegration and erosion of the matrices which is depending upon the vehicle employed. The aging study revealed that the formulations containing G50/13 and G50/13-G44/14 blends undergo some changes during one year of shelf aging. From the results obtained it can be concluded that different gelucire grades and their blends along with hydrophilic polymer could be successesively used to formulate prolong release carbamazepine pesseries. PMID:19450222
In the present investigation an attempt has been made to increase therapeutic efficacy, reduced frequency of administration and improved patient compliance by developing controlled release matrix tablets of verapamil hydrochloride. Verapamil hydrochloride was formulated as oral controlled release matrix tablets by using the polyethylene oxides (Polyox WSR 303). The aim of this study was to investigate the influence of polymer level and type of fillers namely lactose (soluble filler), swellable filler (starch 1500), microcrystalline cellulose and dibasic calcium phosphate (insoluble fillers) on the release rate and mechanism of release for verapamil hydrochloride from matrix tablets prepared by direct compression process. Higher polymeric content in the matrix decreased the release rate of drug. On the other hand, replacement of lactose with anhydrous dibasic calcium phosphate and microcrystalline cellulose has significantly retarded the release rate of verapamil hydrochloride. Biopharmaceutical evaluation of satisfactory formulations were also carried out on New Zealand rabbits and parameters such as maximum plasma concentration, time to reach peak plasma concentration, area under the plasma concentration time curve(0-t) and area under first moment curve(0-t) were determined. In vivo pharmacokinetic study proves that the verapamil hydrochloride from matrix tablets showed prolonged release and were be able to sustain the therapeutic effect up to 24 h. PMID:24019567
Tip vortex cavitation (TVC) suppression by mass injection in the core of the vortex was studied with an elliptical plan-form hydrofoil NACA-66 modified in a re-circulating water tunnel of known nuclei distribution. The chord based Re was O(106) for all experiments. Water and Polyox WSR 301 solution for a range of concentrations (10 to 500pmm) and relative flow rates (Qjet / Qcore of 0.033 to 0.27) were injected. Also, different injection port size and angle of attack were studied. It was found that the TVC suppression effect was different for inception and desinence. The baseline (no injection) inception cavitation number was more than the average negative pressure coefficient, -Cp of the vortex, while mass addition reduced the inception cavitation number to approximately the --Cp value. TVC desinence for the baseline case was found to match the estimated --Cp value and polymer injection provided some cavitation suppression. Flow measurements were made to understand the underlying physics of TVC. The mechanisms and scalability that lead to TVC suppression by mass injection are discussed.
Ganesh, Harish; Chang, Natasha; Yakushiji, Ryo; Ceccio, Steven
The field of ocular drug delivery is one of the interesting and challenging endeavors facing the pharmaceutical scientist. Novel approaches for ophthalmic drug delivery need to be established to increase the ocular bioavailability by overcoming the inherent drawbacks of conventional dosage forms. In situ hydrogels are instilled as drops into the eye and undergoes a sol-to-gel transition in the cul-de-sac, improved ocular bioavailability by increasing the duration of contact with corneal tissue, thereby reducing the frequency of administration. The purpose of the present work was to develop an ophthalmic drug delivery system using three different gelling agents with different mechanisms for in situ gelation of Moxifloxacin hydrochloride, a fluoroquinolone antibiotic. polyox (a pH-sensitive gelling agent), sodium alginate (an ion-sensitive gelling agent), and poloxamer (a temperature-sensitive gelling agent) were employed for the formation of in situ hydrogel along with HPMC K4M as viscofying agent, which increases the residence time of the drug in the ocular cavity. The promising formulations MF(4), MF(5), and MF(9) were evaluated for pH, drug content, in vitro gelation, in vitro drug release, in vivo drug release, ocular irritation, and stability. Percent drug content of 98.2, 98.76, and 99.43%; viscosity of 15.724 × 100, 16.108 × 100, and 15.213 × 100 cP at 20 rpm, cumulative percent release of 75.364, 74.081, and 71.752%, and C (max) of 1,164.16, 1,187.09, and 1,220.58 ng/ml was observed for formulation MF(4), MF(5), and MF(9), respectively. The developed formulations were therapeutically efficacious, stable, and non-irritant and provided sustained release of the drug over 8 h. PMID:22015966
Nanjwade, Basavaraj K; Deshmukh, Rucha V; Gaikwad, Kishori R; Parikh, Kemy A; Manvi, F V