Aggregation studies of benzoporphyrin derivative

2001 ◽  
Vol 79 (5-6) ◽  
pp. 1068-1074 ◽  
Author(s):  
David Delmarre ◽  
Noboru Hioka ◽  
Ron Boch ◽  
Ethan Sternberg ◽  
David Dolphin
Keyword(s):  
Dielectric Constant ◽  
Photodynamic Therapy ◽  
Photophysical Properties ◽  
Equilibrium Constants ◽  
Solvent Mixtures ◽  
Ph Values ◽  
Beer's Law ◽  
Beer’S Law ◽  
Solvent Systems ◽  
Porphyrin Dimers

The photophysical properties of a ring B benzoporphyrin derivative 1,3-diene dimethylester were investigated in solution (water–DMSO mixtures). At low proportions of water in DMSO, the diester obeys Beer's law at all pH values and ionic strengths investigated. For solvent systems containing more than 30% water, the extent of deviation from Beer's law as a function of porphyrin concentration is attributed to formation of porphyrin dimers. Dimerization equilibrium constants (Kd) have been determined in different percentage of solvent mixtures, using absorption and fluorescence spectroscopies, and were found to exhibit a linear correlation between log (Kd) and the inverse of the dielectric constant (log (Kd) = 24.6 – 1060.4 × 1/εmix). This equation permits the calculation of Kd in mixtures of water–DMSO.Key words: porphyrins, dimerization, aggregation, fluorescence, benzoporphyrin derivative, photodynamic therapy, photosensitizers.

Thermodynamics of Ionization of Nitroethane in Water–Ethanol Solvent Mixtures

1974 ◽  
Vol 52 (10) ◽  
pp. 1910-1913 ◽  
Author(s):  
Takeki Matsui ◽  
Loren G. Hepler ◽  
Earl M. Woolley
Keyword(s):  
Mixed Solvent ◽  
Aqueous Ethanol ◽  
Equilibrium Constants ◽  
Glass Electrode ◽  
Solvent Mixtures ◽  
Calorimetric Measurements ◽  
Solvent Systems ◽  
Ionization Of Water ◽  
Thermodynamics Of Ionization ◽  
Acid Ionization

We have made glass electrode measurements that lead to values for the equilibrium constant for acid ionization of nitroethane in water and in aqueous ethanol mixed solvent systems. Calorimetric measurements have led to ΔH0 values for the acid ionization of nitroethane in water and in aqueous ethanol. These results have been combined to yield TΔS0 values for the ionization reactions in water and in aqueous ethanol. Our results have also been combined with previously reported equilibrium constants for ionization of water in aqueous ethanol to obtain thermodynamic data for the neutralization of nitroethane in the various solvent systems.

Photophysical properties and intracellular imaging of water-soluble porphyrin dimers for two-photon excited photodynamic therapy

2009 ◽  
Vol 7 (5) ◽  
pp. 889 ◽  
Author(s):  
Marina K. Kuimova ◽  
Hazel A. Collins ◽  
Milan Balaz ◽  
Emma Dahlstedt ◽  
James A. Levitt ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Photophysical Properties ◽  
Water Soluble ◽  
Intracellular Imaging ◽  
Two Photon ◽  
Water Soluble Porphyrin ◽  
Porphyrin Dimers

Novel UV Spectrophotometric Method for the Quantitative Analysis of CefpodoximeProxetil in Pharmaceutical Formulations by First Derivative Technique

2017 ◽  
Vol 8 (03) ◽  
Author(s):  
Potdar S. S. ◽  
Karajgi S. R. ◽  
Simpi C. C. ◽  
Kalyane N. V.
Keyword(s):  
Quantitative Analysis ◽  
Spectrophotometric Method ◽  
Dosage Form ◽  
Pharmaceutical Formulations ◽  
First Derivative ◽  
Good Linearity ◽  
Beer's Law ◽  
Beer’S Law ◽  
Tablet Dosage ◽  
Ich Guideline

The spectrophotometric method for estimation of CefpodoximeProxetil employed first derivative amplitude UV spectrophotometric method for analysis using methanol as solvent for the drug. CefpodoximeProxetil has absorbance maxima at 235nm and obeys Beer’s law in concentration range 10-50µg/ml with good linearity i.e. r2 about 0.999. The recovery studies established accuracy of the proposed method; result validated according to ICH guideline. Results were found satisfactory and reproducible. The method was successfully for evaluation of CefpodoximeProxetil in tablet dosage form without interference of common excipients.

scholarly journals Estimation of Tadalafil Using Derivative Spectrophotometry in Bulk Material and in Pharmaceutical Formulation

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Zamir G. Khan ◽  
Amod S. Patil ◽  
Atul A. Shirkhedkar
Keyword(s):  
Wavelength Range ◽  
Area Under Curve ◽  
Pharmaceutical Formulation ◽  
Second Order ◽  
Order Derivative ◽  
Uv Spectrophotometry ◽  
First Order ◽  
Beer's Law ◽  
Beer’S Law ◽  
Derivative Uv Spectrophotometry

Four simple, rapid, accurate, precise, reliable, and economical UV-spectrophotometric methods have been proposed for the determination of tadalafil in bulk and in pharmaceutical formulation. “Method A” is first order derivative UV spectrophotometry using amplitude, “method B” is first order derivative UV spectrophotometry using area under curve technique, “method C” is second order derivative UV spectrophotometry using amplitude, and “method D” is second order derivative UV spectrophotometry using area under curve technique. The developed methods have shown best results in terms of linearity, accuracy, precision, and LOD and LOQ for bulk drug and marketed formulation as well. In N,N-dimethylformamide, tadalafil showed maximum absorbance at 284 nm. For “method A” amplitude was recorded at 297 nm while for “method B” area under curve was integrated in the wavelength range of 290.60–304.40 nm. For “method C” amplitude was measured at 284 nm while for “method D” area under curve was selected in the wavelength range of 280.80–286.20 nm. For methods A and B, tadalafil obeyed Lambert-Beer’s law in the range of 05–50 μg/mL while for “methods C and D”, tadalafil obeyed Lambert-Beer’s law in the range of 20–70 μg/mL, and-for “methods A, B, C, and D” the correlation coefficients were found to be > than 0.999.

scholarly journals The nanoscaled metal-organic framework ICR-2 as a carrier of porphyrins for photodynamic therapy

2018 ◽  
Vol 9 ◽  
pp. 2960-2967 ◽  
Author(s):  
Jan Hynek ◽  
Sebastian Jurík ◽  
Martina Koncošová ◽  
Jaroslav Zelenka ◽  
Ivana Křížová ◽  
...  
Keyword(s):  
Inorganic Chemistry ◽  
Photodynamic Therapy ◽  
Photophysical Properties ◽  
Metal Organic Framework ◽  
Metal Organic Frameworks ◽  
Biological Applications ◽  
Nanoparticle Surface ◽  
Metal Organic ◽  
Unsaturated Metal Sites ◽  
First Time

Nanosized porphyrin-containing metal-organic frameworks (MOFs) attract considerable attention as solid-state photosensitizers for biological applications. In this study, we have for the first time synthesised and characterised phosphinate-based MOF nanoparticles, nanoICR-2 (Inorganic Chemistry Rez). We demonstrate that nanoICR-2 can be decorated with anionic 5,10,15,20-tetrakis(4-R-phosphinatophenyl)porphyrins (R = methyl, isopropyl, phenyl) by utilizing unsaturated metal sites on the nanoparticle surface. The use of these porphyrins allows for superior loading of the nanoparticles when compared with commonly used 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin. The nanoICR-2/porphyrin composites retain part of the free porphyrins photophysical properties, while the photodynamic efficacy is strongly affected by the R substituent at the porphyrin phosphinate groups. Thus, phosphinatophenylporphyrin with phenyl substituents has the strongest photodynamic efficacy due to the most efficient cellular uptake.

scholarly journals A spectrophotometric method for determination of fluorophore-to-protein ratios in conjugates of the blue fluorophore 7-amino-4-methylcoumarin-3-acetic acid (AMCA)

1990 ◽  
Vol 38 (1) ◽  
pp. 87-94 ◽  
Author(s):  
M W Wessendorf ◽  
S J Tallaksen-Greene ◽  
R M Wohlhueter
Keyword(s):  
Acetic Acid ◽  
Optical Density ◽  
Extinction Coefficient ◽  
Spectrophotometric Method ◽  
Extinction Coefficients ◽  
Beer's Law ◽  
Beer’S Law ◽  
The Given

7-Amino-4-methylcoumarin-3-acetic acid (AMCA) has been found to be a useful fluorophore for immunofluorescence. The present study describes a spectrophotometric method for determining the ratio of moles AMCA to moles protein (or the f/p ratio) in an AMCA-conjugated IgG. The concentration of a substance absorbing light can be determined spectrophotometrically using Beer's Law: Absorbance = Concentration x Extinction coefficient. From Beer's law, one can derive the following formula for determining the f/p ratio of AMCA-IgG conjugates: f/p = (epsilon 280IgG).A350 - (epsilon 350IgG).A280/(epsilon 350AMCA).A280 - (epsilon 280AMCA).A350 where A is the optical density of the conjugate at the given wavelength and epsilon is the extinction coefficient of a substance at the wavelength specified. Using conjugates of model proteins, it was found that the extinction coefficients of the AMCA moiety of AMCA-conjugated protein were 1.90 x 10(4) at 350 nm and 8.29 x 10(3) at 280 nm. Similarly, it was found that the extinction coefficients of swine IgG were 1.56 x 10(3) at 350 nm and 1.26 x 10(5) at 280 nm. Thus, for AMCA-conjugated swine IgG: f/p = (1.26 x 10(5)).A350 - (1.56 x 10(3)).A280/(1.47 x 10(4)).A280 - (6.42 x 10(3)).A350 [corrected]. Based on this formula, the f/p ratios of some AMCA-IgG conjugates useful for immunohistochemistry have been found to range between 6 and 24.

Sign in / Sign up

Export Citation Format

Share Document