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Shannon Moore - One of the best experts on this subject based on the ideXlab platform.
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dehydration and hydration ktnetics phase change solubility and dissolution behavior of Fenoprofen calcium
Drug Development and Industrial Pharmacy, 1995Co-Authors: Raj Sathe, Shannon MooreAbstract:AbstractThe role of water of hydration on the crystal structure, the solubility and the rate of dissolution of Fenoprofen calcium dihydrate was examined. The rate of dehydration of Fenoprofen calcium dihydrate at 0% relative humidity (R.H.) increased from 0.0400 to 0.7488 fraction dehydratedhour over a temperature range of 50°C to 80 °C and appeared to occur by a combination of diffusion and nucleation processes. The enthalpy of dehydration was 21.897 kcal/mole. Hydration of dehydrated Fenoprofen calcium occurred rapidly at 100% R.H. X-ray powder diffraction analysis showed that the upon dehydration Fenoprofen calcium dihydrate underwent a change in its crystal structure to form anhydrous Fenoprofen calcium. The rate of dissolution of Fenoprofen calcium dihydrate tablets at 37°C was not significantly different than that of tablets containing anhydrous Fenoprofen. The enthalpies of solution (δHsol) of Fenoprofen calcium dihydrate and anhydrous Fenoprofen calcium were 2.0504 and 3.5583 kcaYmole respectively...
Thomas Rades - One of the best experts on this subject based on the ideXlab platform.
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using terahertz pulsed spectroscopy to study crystallinity of pharmaceutical materials
Chemical Physics Letters, 2004Co-Authors: Clare J Strachan, Thomas Rades, David A Newnham, Keith C Gordon, M Pepper, P F TadayAbstract:The application of terahertz pulsed spectroscopy to polymorphic, liquid crystalline and amorphous forms of pharmaceutical compounds has been investigated. The different polymorphic forms of carbamazepine and enalapril maleate exhibit distinct terahertz absorbance spectra. In contrast to crystalline indomethacin and Fenoprofen calcium, amorphous indomethacin and liquid crystalline Fenoprofen calcium show no absorption modes, which is likely to be due to a lack of order. These findings suggest that the modes observed are due to crystalline phonon and possibly hydrogen-bonding vibrations. The large spectral differences between different forms of the compounds studied is evidence that terahertz pulsed spectroscopy is well-suited to distinguishing crystallinity differences in pharmaceutical compounds.
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Physical stability and solubility of the thermotropic mesophase of Fenoprofen calcium as pure drug and in a tablet formulation.
International Journal of Pharmaceutics, 2002Co-Authors: James E. Patterson, Andrew R Bary, Thomas RadesAbstract:The aim of this study was to investigate and compare the physical stability and solubility of the liquid crystalline form of Fenoprofen calcium as pure drug and in a proprietary tablet formulation (Nalfon), and to investigate if a simple heat treatment of a proprietary tablet containing Fenoprofen calcium may lead to a physically stable formulation with enhanced dissolution rate and apparent solubility. The liquid crystalline form of Fenoprofen calcium (thermotropic mesophase) was prepared by heating the crystalline drug to 125 degrees C to remove the water of crystallisation. Differential scanning calorimetry investigation revealed an endothermic peak at 89 degrees C upon heating (liquid crystal formation) attributable to water loss from the crystalline dihydrate. The liquid crystalline order was maintained upon cooling. No interference of tablet excipients with the thermal behaviour of the drug in the tablet formulation was observed. The crystalline dihydrate and liquid crystalline forms of Fenoprofen calcium could be differentiated by diffuse reflectance infra-red spectroscopy and X-ray powder diffraction, both as pure drug and in tablet formulation. The supercooled liquid crystal (thermotropic reversed hexagonal phase) alone and in preheated and ground tablets was physically stable when stored in a dry environment or at 33% relative humidities (RH) at both 20 and 40 degrees C for 2 months. At 40 degrees C and 75% RH the supercooled mesophase extensively converted to the crystalline dihydrate within 6 days. Liquid crystalline Fenoprofen calcium stored at 20 degrees C and 75% RH showed only partial dihydrate conversion after 2 months of storage. The solubility of the crystalline dihydrate alone and from the tablet formulation was 2.8+/-0.2 mg/ml and 3.0+/-0.2 mg/ml (mean+/-s.d.), respectively, (not significantly different), whereas the maximum solubility of the liquid crystal was 5.0+/-0.3 mg/ml (mean+/-s.d.) and 6.9+/-0.6 mg/ml (mean+/-s.d.), respectively (significantly different). The difference in maximum solubility between the crystalline dihydrate form of Fenoprofen calcium and the Fenoprofen calcium mesophase was highly significant, for both the pure drugs and the tablet formulations. The dissolution rate of the liquid crystalline Fenoprofen calcium in preheated, intact tablets was significantly lower than that of the crystalline form in non-preheated tablets. Gross visual changes and scanning electron microscopy indicated that the disintegration properties of the tablet may be detrimentally effected by heating the tablet to 125 degrees C, diminishing the beneficial effect of improved solubility of the liquid crystal. The study has shown that conversion of the crystalline form of Fenoprofen calcium to the liquid crystal can enhance the apparent solubility of the pure drug and the drug in presence of tablet excipients, but that the conversion should be performed before tablet formulation in order to increase dissolution of this poorly water-soluble drug.
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Interactions between Fenoprofen sodium and poly (ethylene oxide)
European journal of pharmaceutics and biopharmaceutics : official journal of Arbeitsgemeinschaft fur Pharmazeutische Verfahrenstechnik e.V, 1998Co-Authors: Thomas Rades, C.c Mueller-goymannAbstract:Abstract Interactions of the amphiphilic drug Fenoprofen sodium (FNa) in solution below and above its critical micelle concentration with poly (ethylene oxide) (PEO) of different chain length (PEO 400 to PEO 20 000) and between a liquid crystalline formulation of Fenoprofen (FLC; containing FNa, Fenoprofen acid and water) and PEO were investigated, using surface tension measurements, viscometry, cloud point temperature measurements, [ 1 H]NMR, polarised light microscopy, transmission electron microscopy, and differential scanning calorimetry. Interaction between FNa solutions and PEO: the investigations suggest that an interaction starts below the critical micelle concentration (CMC) of FNa. This can be concluded from [ 1 H]NMR experiments (an upfield shift of the PEO proton signal was found at FNa concentrations below the CMC of FNa), surface tension measurements (absence of a critical association concentration) and cloud point temperature determinations. The surfactant does not seem to bind quantitatively on the PEO molecules (a higher FNa concentration was needed to cause the same upfield shift of the PEO proton signal than for more lipophilic surfactants, and no plateau phase in the surface tension reduction isotherm could be determined).Interactions were found to be independent from the chain length of the PEO. Interactions between FLC and PEO/pluronics: partial or complete dissolution of the Fenoprofen mesophase (detected by [ 1 H]NMR, polarised light microscopy and transmission electron microscopy) occurred after addition of PEO at concentrations between 2 and 10% (w/w), independent from the molecular weight of the PEO. A comparable amount of water added to the liquid crystalline samples does not change the mesophase into a liquid crystalline dispersion or a micellar solution. The liquid crystalline particles in the dispersion formed by the addition of PEO, had a higher transition temperature into an isotropic phase (between 54°C and 57°C), than in liquid crystalline dispersions without polymer (40°C). The interactions between FNa and PEO can be interpreted in terms of a hydrophobic interaction with an association of the drug molecules on the polymer, i.e. the interaction between FNa and PEO occurs at a molecular rather than a micellar level. The interaction leads to a dissolution of the Fenoprofen liquid crystal and the formation of an isotropic phase. No phase separation of the oily, amorphous, practically water insoluble Fenoprofen acid could be found. Addition of PEO also seems to affect the composition of the remaining mesophase.
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Investigations on the micellisation behaviour of Fenoprofen sodium
International Journal of Pharmaceutics, 1997Co-Authors: Thomas Rades, Christel C. Müller-goymannAbstract:Abstract The aim of the present study was to investigate the micellisation behaviour of the non-steroidal anti-inflammatory drug Fenoprofen sodium in aqueous solutions. The methods used were foam stability measurements, 1H-NMR, solubilisation, photon correlation spectroscopy (PCS) and transmission electron microscopy (TEM). Results from surface tension measurements performed in a previous study were included. A great discrepancy between critical values from different experimental methods was found. Methods that detect changes in the surface properties of aqueous Fenoprofen sodium solutions suggest that the critical concentration was 1.5∗10−2 mol/l, while methods that detect changes in the bulk phase led to a critical concentration of 1.2∗10−1 mol/l. In the concentration range between 1.5∗10−2 and about 1.0∗10−1 mol/l no formation of aggregates could be detected (concluded from the absence of an upfield shift of the phenyl proton signals in the NMR measurements and the finding that the oily, practically water insoluble Fenoprofen acid could not be solubilised by Fenoprofen sodium solutions below concentrations of 1.0∗10−1 mol/l Fenoprofen sodium). Association of Fenoprofen sodium molecules to micelles starts at concentrations between 1.0 and 1.2∗10−1 mol/l. In conclusion, the determination of the critical micelle concentration from surface tension measurements does not allow the determination of micellisation phenomena in the case of Fenoprofen sodium. Further methods are required to assure micellisation. Photon correlation spectroscopy and TEM support the assumption that Fenoprofen sodium forms disclike micelles, although with both methods the micelle size could not exactly be determined. From differences in the chemical shift of the two phenyl rings of Fenoprofen sodium it was concluded that the micelles have a bilayer or partially overlapping bilayer structure.
Lyska Emerson - One of the best experts on this subject based on the ideXlab platform.
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Interaction of valproic acid with nonsteroidal antiinflammatory drugs mefenamic acid and Fenoprofen in normal and uremic sera: Lack of interaction in uremic sera due to the presence of endogenous factors
Therapeutic drug monitoring, 1996Co-Authors: Amitava Dasgupta, Lyska EmersonAbstract:Valproic acid is an anticonvulsant that is strongly bound to serum albumin. The nonsteroidal antiinflammatory drugs mefenamic acid and Fenoprofen are also strongly bound to albumin. We observed significant displacement of valproic acid from protein binding by mefenamic acid and Fenoprofen at both therapeutic and slightly above therapeutic concentrations. The concentration of free valproic acid was higher in the uremic serum, as expected, but we observed no further displacement of valproic acid in the presence of mefenamic acid and Fenoprofen. Known uremic compounds, hippuric acid and indoxyl sulfate, did not inhibit the interactions between valproic acid and mefenamic acid or Fenoprofen. Treatment of uremic serum with activated charcoal at pH 3.0 removes endogenous interfering factors and corrects the binding defect of uremic serum for valproic acid. We observed significant displacement of valproic acid from protein binding by both mefenamic acid and Fenoprofen in uremic serum after charcoal treatment. We conclude that endogenous factors are present in uremic sera that block interaction of valproic acid with mefenamic acid and Fenoprofen.
Raj Sathe - One of the best experts on this subject based on the ideXlab platform.
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dehydration and hydration ktnetics phase change solubility and dissolution behavior of Fenoprofen calcium
Drug Development and Industrial Pharmacy, 1995Co-Authors: Raj Sathe, Shannon MooreAbstract:AbstractThe role of water of hydration on the crystal structure, the solubility and the rate of dissolution of Fenoprofen calcium dihydrate was examined. The rate of dehydration of Fenoprofen calcium dihydrate at 0% relative humidity (R.H.) increased from 0.0400 to 0.7488 fraction dehydratedhour over a temperature range of 50°C to 80 °C and appeared to occur by a combination of diffusion and nucleation processes. The enthalpy of dehydration was 21.897 kcal/mole. Hydration of dehydrated Fenoprofen calcium occurred rapidly at 100% R.H. X-ray powder diffraction analysis showed that the upon dehydration Fenoprofen calcium dihydrate underwent a change in its crystal structure to form anhydrous Fenoprofen calcium. The rate of dissolution of Fenoprofen calcium dihydrate tablets at 37°C was not significantly different than that of tablets containing anhydrous Fenoprofen. The enthalpies of solution (δHsol) of Fenoprofen calcium dihydrate and anhydrous Fenoprofen calcium were 2.0504 and 3.5583 kcaYmole respectively...
Jiaxiang Wang - One of the best experts on this subject based on the ideXlab platform.
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albumin supplement affects the metabolism and metabolism related drug drug interaction of Fenoprofen enantiomers
Chirality, 2015Co-Authors: Nan Wang, Feng Wang, Yu Meng, Guohui Yang, Juwu Chen, Jiaxiang WangAbstract:The influence of albumin towards the metabolism behavior of Fenoprofen enantiomers and relevant drug–drug interaction was investigated in the present study. The metabolic behavior of Fenoprofen enantiomers was compared in a phase II metabolic incubation system with and without bovine serum albumin (BSA). BSA supplement increased the binding affinity parameter (Km) of (R)-Fenoprofen towards human liver microsomes (HLMs) from 148.3 to 214.4 μM. In contrast, BSA supplement decreased the Km of (S)-Fenoprofen towards HLMs from 218.2 to 123.5 μM. For maximum reaction velocity (Vmax), the addition of BSA increased the Vmax of (R)-Fenoprofen from 1.3 to 1.6 nmol/min/mg protein. In the contrast, BSA supplement decreased the Vmax value from 3.3 to 1.5 nmol/min/mg protein. Andrographolide–Fenoprofen interaction was used as an example to investigate the influence of BSA supplement towards Fenoprofen-relevant drug–drug interaction. The addition of 0.2% BSA in the incubation system significantly decreased the inhibition potential of andrographolide towards (R)-Fenoprofen metabolism (P < 0.001). Different from (R)-Fenoprofen, the addition of BSA significantly increased the inhibition potential of andrographolide towards the metabolism of (S)-Fenoprofen. BSA supplement also changed the inhibition kinetic type and parameter of andrographolide towards the metabolism of (S)-Fenoprofen. In conclusion, albumin supplement changes the metabolic behavior of Fenoprofen enantiomers and the Fenoprofen–andrographolide interaction. Chirality 27:436–440, 2015. © 2015 Wiley Periodicals, Inc.
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Albumin Supplement Affects the Metabolism and Metabolism-Related Drug–Drug Interaction of Fenoprofen Enantiomers
Chirality, 2015Co-Authors: Nan Wang, Feng Wang, Yu Meng, Guohui Yang, Juwu Chen, Jiaxiang WangAbstract:The influence of albumin towards the metabolism behavior of Fenoprofen enantiomers and relevant drug–drug interaction was investigated in the present study. The metabolic behavior of Fenoprofen enantiomers was compared in a phase II metabolic incubation system with and without bovine serum albumin (BSA). BSA supplement increased the binding affinity parameter (Km) of (R)-Fenoprofen towards human liver microsomes (HLMs) from 148.3 to 214.4 μM. In contrast, BSA supplement decreased the Km of (S)-Fenoprofen towards HLMs from 218.2 to 123.5 μM. For maximum reaction velocity (Vmax), the addition of BSA increased the Vmax of (R)-Fenoprofen from 1.3 to 1.6 nmol/min/mg protein. In the contrast, BSA supplement decreased the Vmax value from 3.3 to 1.5 nmol/min/mg protein. Andrographolide–Fenoprofen interaction was used as an example to investigate the influence of BSA supplement towards Fenoprofen-relevant drug–drug interaction. The addition of 0.2% BSA in the incubation system significantly decreased the inhibition potential of andrographolide towards (R)-Fenoprofen metabolism (P