Polyethylene oxide (Polyox) and carrageenan based solvent cast films have been formulated as dressings for drug delivery to wounds. Films plasticised with glycerol were loaded with streptomycin (30%, w/w) and diclofenac (10%, w/w) for enhanced healing effects in chronic wounds. Blank and drug loaded films were characterised by texture analysis (for mechanical and mucoadhesive properties), scanning electron microscopy, differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy. In addition, swelling, in vitro drug release and antibacterial studies were conducted to further characterise the films. Both blank and drug loaded films showed a smooth, homogeneous surface morphology, excellent transparency, high elasticity and acceptable tensile (mechanical) properties. The drug loaded films showed a high capacity to absorb simulated wound fluid and significant mucoadhesion force which is expected to allow effective adherence to and protection of the wound. The films showed controlled release of both streptomycin and diclofenac for 72 h. These drug loaded films produced higher zones of inhibition against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli compared to the individual drugs zones of inhibition. Incorporation of streptomycin can prevent and treat chronic wound infections whereas diclofenac can target the inflammatory phase of wound healing to relieve pain and swelling. PMID:23228898
Boateng, Joshua S; Pawar, Harshavardhan V; Tetteh, John
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
Topics include: Molecular Geology; Modeling Tools for Geochemical Systems, including Potential Energy Functions; Obtaining Model Parameters; Example Systems, including Broensted AcidBase Reactions, Water, Hydroxide, and Oxide Exchange Kinetics, and Polyox...
J. R. Rustad
Flow of aqueous solutions of Polyox WSR-301, with concentrations of 1.0 to 200 wppm, past circular cylinders was investigated in the drag-transition region of Reynolds numbers. Drag force, pressure distribution, and separation angle were measured on cylin...
T. Sarpkaya P. G. Rainey
The objective of this research was to stabilize a heat-labile novel prodrug of ?9-tetrahydrocannabinol (THC), THC-hemiglutarate (THC-HG), in polyethylene oxide (PEO) [PolyOx® WSR N-80 (PEO N-80), MW 200,000 Daltons] polymeric matrix systems produced by hot-melt fabrication for systemic delivery of THC through the oral transmucosal route. For this purpose, the effects of processing conditions (processing temperature and heating duration), plasticizer
Sridhar Thumma; Mahmoud A. ElSohly; Shuang-Qing Zhang; Waseem Gul; Michael A. Repka
The present study was carried out with an objective of preparation and in vitro evaluation of floating tablets of hydroxypropyl methyl cellulose (HPMC) and polyethylene oxide (PEO) using ranitidine hydrochloride as a model drug. The floating tablets were based on effervescent approach using sodium bicarbonate a gas generating agent. The tablets were prepared by dry granulation method. The effect of polymers concentration and viscosity grades of HPMC on drug release profile was evaluated. The effect of sodium bicarbonate and stearic acid on drug release profile and floating properties were also investigated. The result of in vitro dissolution study showed that the drug release profile could be sustained by increasing the concentration of HPMC K15MCR and Polyox WSR303. The formulation containing HPMC K15MCR and Polyox WSR303 at the concentration of 13.88% showed 91.2% drug release at the end of 24 hours. Changing the viscosity grade of HPMC from K15MCR to K100MCR had no significant effect on drug release profile. Sodium bicarbonate and stearic acid in combination showed no significant effect on drug release profile. The formulations containing sodium bicarbonate 20 mg per tablet showed desired buoyancy (floating lag time of about 2 minutes and total floating time of >24 hours). The present study shows that polymers like HPMC K15MCR and Polyox WSR303 in combination with sodium bicarbonate as a gas generating agent can be used to develop sustained release floating tablets of ranitidine hydrochloride. PMID:23493037
Gharti, Kp; Thapa, P; Budhathoki, U; Bhargava, A
Anionic polymer sodium carboxymethylcellulose (CELLOGEN® HP-HS and\\/or HP-12HS) was investigated for its ability to influence\\u000a the release of three model drugs propranolol hydrochloride, theophylline and ibuprofen from polyethylene oxide (POLYOX™ WSR\\u000a 1105 and\\/or Coagulant) hydrophilic matrices. For anionic ibuprofen and non-ionic theophylline, no unusual\\/unexpected release\\u000a profiles were obtained from tablets containing a mixture of two polymers. However, for cationic propranolol
Dasha Palmer; Marina Levina; Ali Nokhodchi; Dennis Douroumis; Tom Farrell; Ali Rajabi-Siahboomi
The successful development of compressed ODTs utilises low compression forces to create a porous structure whereby excipients are added to enhance wicking/swelling action or provide strength to the fragile tablet framework. In this work, a systematic investigation comparing materials from two different categories was employed to understand their functionality in binary mixture tablets of the most commonly used diluent mannitol. Cellulose based excipients such as HPC (SSL-SFP), L-HPC (NBD-022) and MCC (Avicel PH-102) were compared with non-cellulosic materials such as PEO (POLYOX WSR N-10) and Crospovidone (XL-10). Pure excipient properties were studied using Heckel Plot, compressibility profile, SEM and XRPD, whereas the prepared binary mixture compacts were studied for hardness, disintegration time and friability. Results from our investigation provide insight into differences encountered in product performance of ODT upon inclusion of additional materials. For example, non-cellulosic excipients Polyox and Crospovidone showed higher plasticity (Py values 588 and 450MPa) in pure form but not in binary mixtures of mannitol. Cellulosic excipients, nonetheless, offer faster disintegration (<30 sec) specifically L-HPC and MCC tablets. Disintegration time for tablets with fully substituted-HPC was prolonged (200-500 sec) upon increasing concentration between 1-10% due to gelation/ matrix formation. It can be concluded that despite the reasonably good plasticity of both cellulosic and noncellulosic excipients in pure form, the mechanical strength in binary mixtures is negatively impacted by the fragmentation/ fracture effect of mannitol. PMID:24655059
Al-Khattawi, Ali; Iyire, Affiong; Dennison, Tom; Dahmash, Eman; Bailey, Clifford J; Smith, Julian; Rue, Peter; Mohammed, Afzal R
Floating pulsatile is combined approach designed according to circadian rhythm to deliver the drug at right time, in right quantity and at right site as per pathophysiological need of disease with prolong gastric residence and lag phase followed by burst release. As the migraine follows circadian rhythm in which headache is more painful at the awakening time, the dosage form should be given during night time to release drug when pain get worsen. Present work deals with formulation and optimization of floating pulsatile tablet of sumatriptan succinate. Core tablet containing crospovidone as superdisintegrant (10%) showed burst release. Lag time was maintained using swellable polymer as polyoxN12K and xanthum gum. 3(2) experimental design was carried out. Developed formulations were evaluated for physical characteristics, in vitro and in vivo study. Optimized batch F2 with concentration of polyox N12K (73.43%) and xanthum gum (26.56%) of total polymer weight showed floating lag time 15±2 sec, drug content 99.58±0.2 %, hardness 6±0.2 Kg/cm(2) and drug release 99.54±2% with pulsatile manner followed lag period of 7±0.1h. In vivo x-ray study confirms prolong gastric residence of system. Programmable pulsatile release has been achieved by formulation F2 which meet demand of chronotherapeutic objective of migraine. PMID:24893996
Jagdale, Swati C; Pawar, Chandrakala R
This study investigated the processing parameters and formulation factors on the bioadhesive properties, temperature stability properties, and drug release properties of miconazole in PolyOx® and Klucel® matrix systems produced by Hot-melt Extrusion (HME) technology. Miconazole incorporated into these matrix systems were found to be stable for 8 months by X-ray diffraction (XRD). The addition of miconazole increased area under the curve (AUC) at contact time intervals of 30 and 60 sec, while the bioadhesion decreased with an increase in processing temperatures. The release profiles suggest that a sustained release of miconazole was observed from all of the tested HME film formulations for approximately 10 h. The release from the optimal HME film extruded at 205°C was found to be significantly different than that extruded at 190°C. Therefore, this matrix system may address the present shortcomings of currently available therapy for oral and pharyngeal candidiasis. PMID:24550099
Chen, Meiwan; Lu, Jiannan; Deng, Weibin; Singh, Abhilasha; Mohammed, Noorullah Naqvi; Repka, Michael A; Wu, Chuanbin
This study was aimed to develop an ascending release push-pull osmotic pump (APOP) system with a novel mechanism and an easy manufacture process. Theoretical analysis showed that the key to obtain the non-zero order drug release was to break the balance between the drug suspension release rate in the drug layer and the swelling rate of the core, and an ascending drug release rate was achieved when the former was slower than the latter. A polymer (Polyox WSR N-12K) was introduced as a suspension agent in drug layer to slow down the hydration rate of drug layer. Influence of the composition of drug layer (PEO category, total amount, drug loading and fraction of NaCl), push layer (NaCl amount), and also the level of coating weight gain on the drug release profiles was investigated. Observation of hydration state was estimated by taking photos, and also was confirmed by the theories. Paliperidone was delivered successfully by APOP at an ascending release rate up to 20 h in vitro. The in vivo plasma concentration of paliperidone in beagle dogs increased gradually up to 19 h. The APOP with an easy manufacture process was a promising strategy to deliver drug at an ascending rate. PMID:24095815
Xu, Heming; Li, Zhao; Pan, Hao; Zhang, Zhihong; Liu, Dandan; Tian, Baocheng; Ma, Shilin; Song, Shilong; Pan, Weisan
Anionic polymer sodium carboxymethylcellulose (CELLOGEN® HP-HS and/or HP-12HS) was investigated for its ability to influence the release of three model drugs propranolol hydrochloride, theophylline and ibuprofen from polyethylene oxide (POLYOX™ WSR 1105 and/or Coagulant) hydrophilic matrices. For anionic ibuprofen and non-ionic theophylline, no unusual/unexpected release profiles were obtained from tablets containing a mixture of two polymers. However, for cationic propranolol HCl, a combination of polyethylene oxide (PEO) with sodium carboxymethylcellulose (NaCMC) produced a significantly slower drug release compared to the matrices with single polymers. The potential use of this synergistic interaction can be a design of new extended release pharmaceutical dosage forms with a more prolonged release (beyond 12 h) using lower polymer amount, which could be particularly beneficial for freely water-soluble drugs, preferably for once daily oral administration. In order to explain changes in the obtained drug release profiles, Fourier transform infrared absorption spectroscopy was performed. A possible explanation for the more prolonged propranolol HCl release from matrices based on both PEO and NaCMC may be due to a chemical bond (i.e. ionic/electrostatic intermolecular interaction) between amine group of the cationic drug and carboxyl group of the anionic polymer, leading to a formation of a new type/form of the active (i.e. salt) with sustained release pattern. PMID:21710334
Palmer, Dasha; Levina, Marina; Nokhodchi, Ali; Douroumis, Dennis; Farrell, Tom; Rajabi-Siahboomi, Ali
Wafers combining weight ratios of Polyox with carrageenan (75/25) or sodium alginate (50/50) containing streptomycin and diclofenac were prepared to improve chronic wound healing. Gels were freeze-dried using a lyophilisation cycle incorporating an annealing step. Wafers were characterised for morphology, mechanical and in vitro functional (swelling, adhesion, drug release in the presence of simulated wound fluid) characteristics. Both blank (BLK) and drug-loaded (DL) wafers were soft, flexible, elegant in appearance and non-brittle in nature. Annealing helped to improve porous nature of wafers but was affected by the addition of drugs. Mechanical characterisation demonstrated that the wafers were strong enough to withstand normal stresses but also flexible to prevent damage to newly formed skin tissue. Differences in swelling, adhesion and drug release characteristics could be attributed to differences in pore size and sodium sulphate formed because of the salt forms of the two drugs. BLK wafers showed relatively higher swelling and adhesion than DL wafers with the latter showing controlled release of streptomycin and diclofenac. The optimised dressing has the potential to reduce bacterial infection and can also help to reduce swelling and pain associated with injury due to the anti-inflammatory action of diclofenac and help to achieve more rapid wound healing. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci. PMID:24700434
Pawar, Harshavardhan V; Boateng, Joshua S; Ayensu, Isaac; Tetteh, John
Texture analysis is a new approach in pharmaceutical research and development; this study evaluated the correlation between drug dissolution and polymer hydration from a modified release matrix tablet of pseudoephedrine hydrochloride using a texture analyzer. A series of matrix tablets of pseudoephedrine was designed and prepared. Modified drug release was achieved by combined use of matrix excipients Polyox WSR301 (PEO) and Compritol 888ATO (GB). Dissolution profiles of the tablets were assessed using USP Method II. Polymer swelling behaviors during dissolution were measured using a texture analyzer. Increase in proportion of PEO and GB in the formulation reduced drug dissolution within the first 90 min. However, drug release was complete in 6h due to high aqueous solubility of pseudoephedrine. Linear correlations were observed among drug dissolution, polymer content and parameters of texture analysis including hydrogel thickness and AUC(TA) for formulations that contained hydrophilic PEO. The study demonstrated a unique application of a texture analyzer in characterization of modified release matrix tablets. PMID:17548178
Li, Hongtao; Gu, Xiaochen
There are only a few solid state humidity sensors available today. Most of those sensors use a porous oxide material as a principal part of the device. The devices work on the basis of a change in resistance as the moisture in the air varies. In this experiment, two solid state humidity sensors have been developed for use under practical conditions. One is a Polymer Oxide Semiconductor device with a POLYOX film that absorbs the moisture from the air. The amount of water dipoles absorbed by the polymer is a function of relative humidity. This sensor can measure relative humidity from 20% to 90%. The other is a Dew Point sensor. The sensor is in contact with the upper surface of a miniature Peltier cooler. Water molecules deposited on the sensor surface cause the electrical current through the sensor to increase. The operator adjusts the temperature of the Peltier cooler until a saturated current through the sensor is reached. About one min. is required to measure low relative humidities. The Dew Point sensor can measure a range of relative humidities of 30% to 80%.
We discuss a mechanical experimental model of a flexible sheet swimming with a prescribed wave pattern through a fluid. We are motivated by a need for a fundamental understanding of microorganism locomotion through non-Newtonian fluids. To simplify the problem, we suspend a tall flexible cylindrical sheet concentric within a cylindrical tank filled with the fluid. Torque free boundary conditions are imposed by supporting the flexible sheet and the tank with friction-free ball-bearings. A traveling wave is imposed on the sheet with a pair of rollers in the azimuthal direction. We first show that the swimming speed is linear with respect to the phase velocity of the traveling wave for a viscous Newtonian fluid. Then we show that the system is essentially two dimensional as the results do not depend on the height of fluid in the tank. We measure swimming speed in Polyox-water mixtures and Sodium CMC solutions as a function of wave speed. We again demonstrate linear response in the swimming speeds, which also decrease in these viscoelastic fluids relative to the Newtonian case as wave speed increases. Decrease in swimming speed is observed with increase in viscoelasticity of the fluids. We then discuss the dependence of swimming speed on the Deborah number of the fluids.
Dasgupta, Moumita; Berhanu, Michael; Kudrolli, Arshad; Liu, Bin; Breuer, Kenneth; Powers, Thomas
We discuss a mechanical experimental model of a flexible sheet swimming with a prescribed wave pattern - a Taylor swimmer - through a fluid. Our study is motivated by a need for a fundamental understanding of microorganism locomotion through non-Newtonian fluids. In order to simplify the problem, we suspend a tall flexible cylindrical sheet concentric within a cylindrical tank filled with the fluid. Torque free boundary conditions are imposed by supporting the flexible sheet and the tank with friction-free ball-bearings. A traveling wave is imposed on the sheet with a pair of rollers in the azimuthal direction. We first demonstrate a linear response in the swimming velocity of the sheet with respect to its phase velocity in a viscous Newtonian fluid. Further, we show that the analytical system is essentially two dimensional by varying the height of fluid in the tank. We then discuss measurements of swimming speed in Polyox-water mixtures as a function of wave speed. We demonstrate that the swimming speed in this viscoelastic fluid decrease relative to the Newtonian case as wave speed is increased. We will further discuss the dependence of swimming speed on Deborah number and other characteristics of the fluid.
Dasgupta, Moumita; Berhanu, Michael; Kudrolli, Arshad; Fu, Henry; Breuer, Kenneth; Powers, Thomas
The aim of this study was to formulate extended release compression coated core tablets of fenoterol hydrobromide, a selective beta(2) adrenergic receptor agonist, in an attempt to prevent nocturnal asthma. Two hydrophilic polymers viz Kollidon SR, Polyox WSR 303 and a hydrophobic one (Precirol ATO5) were employed. Compression coated tablets were formulated by preparing a core tablet containing 7.5 mg drug and various amounts of polymer and Emcompress then compressed coated with the same polymeric materials. For comparison purpose different matrix tablets were also prepared employing the same polymers. In-vitro release studies were carried out at different pH (1.2 and 6.8). Pharmacokinetics of extended release tablets as well as commercially available immediate release tablets (Berotec) were studied after oral administration to beagle dogs using a new developed LC-MS/MS method with a lower limit of quantification of 1 ng/ml. Fenoterol release from compression coated tablets was significantly lower than matrix tablets. The mechanism of release was changed with the nature and content of polymer. The release pattern of drug from F16 containing 40 mg Kollidon SR divided in the core tablet (15 mg) and the rest in the compressed coat (25 mg) showed a typical zero order release kinetic that could extend drug release >10 h and reasonable time for 75% to be released (t(75)) (8.92 h). When compared to immediate release Berotec tablet the MRT was significantly extended from 7.03 +/- 0.76 to 10.93 +/- 1.25 h (P < 0.001) and HVD(t 50%Cmax) was also significantly extended from 2.71 +/- 0.68 to 6.81 +/- 0.67 h with expected prevention of nocturnal asthma. PMID:18770048
Elshafeey, Ahmed H; Sami, Elshaimaa I
The aim of this study was to formulate extended release compression coated core tablets of fenoterol hydrobromide, a selective ?2 adrenergic receptor agonist, in an attempt to prevent nocturnal asthma. Two hydrophilic polymers viz Kollidon® SR, Polyox® WSR 303 and a hydrophobic one (Precirol® ATO5) were employed. Compression coated tablets were formulated by preparing a core tablet containing 7.5 mg drug and various amounts of polymer and Emcompress® then compressed coated with the same polymeric materials. For comparison purpose different matrix tablets were also prepared employing the same polymers. In-vitro release studies were carried out at different pH (1.2 and 6.8). Pharmacokinetics of extended release tablets as well as commercially available immediate release tablets (Berotec®) were studied after oral administration to beagle dogs using a new developed LC-MS/MS method with a lower limit of quantification of 1 ng/ml. Fenoterol release from compression coated tablets was significantly lower than matrix tablets. The mechanism of release was changed with the nature and content of polymer. The release pattern of drug from F16 containing 40 mg Kollidon® SR divided in the core tablet (15 mg) and the rest in the compressed coat (25 mg) showed a typical zero order release kinetic that could extend drug release >10 h and reasonable time for 75% to be released (t75) (8.92 h). When compared to immediate release Berotec® tablet the MRT was significantly extended from 7.03?±?0.76 to 10.93?±?1.25 h (P?0.001) and HVDt 50%Cmax was also significantly extended from 2.71?±?0.68 to 6.81?±?0.67 h with expected prevention of nocturnal asthma.
Sami, Elshaimaa I.