Telmisartan is a poorly soluble drug used in treatment of hypertension. There is a recent interest to use pluronic for improving the solubility and bioavailability of these drugs. In this study the interaction of telmisartan with P123 and F127 has been carried out using steady state and time dependent fluorescence study. Quenching of telmisartan fluorescence by potassium iodide is controlled by interactions arising from collisions and complex formation. A comparison of the fluorescence of telmisartan in pluronics with the well understood fluorescence of 8-anilino-1-naphthalene-sulfonic acid, a known fluorescent molecular probe, indicates that telmisartan is generally present in a relatively polar microenvironment with restricted diffusive motion.© 2013 Elsevier B.V. All rights reserved.

Ashok Kumar Mishra

Department Of Chemistry

Biochemistry

naphthalene

Quenching

Complex formations

DIFFUSIVE MOTIONS

Fluorescence studies

Pluronics

POLAR MICROENVIRONMENT

POORLY SOLUBLE DRUGS

TELMISARTAN

TRIBLOCK POLYMERS

Fluorescence

8 anilino 1 naphthalenesulfonic acid

8-Anilino-1-naphthalenesulfonic acid

benzimidazole derivative

benzoic acid derivative

PLURONIC BLOCK COPOLYMER P123

Poloxamer

POTASSIUM IODIDE

article

chemistry

spectrofluorometry

Temperature

PLURONIC

Anilino Naphthalenesulfonates

Benzimidazoles

Benzoates

POLOXALENE

Spectrometry, Fluorescence

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy

Surfactant induced changes in the transition temperature of Pluronic F127 have been studied using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and fluorescence spectroscopy. The analysis shows that ionic surfactants (cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS)) significantly alter the transition temperature of PF127, whereas the effect of a nonionic surfactant (Tween20) is not significant. The sol-gel transition temperature decreases from PF127 (22 °C) to PF127+TW20 (21 °C) to PF127+CTAB (18 °C), whereas there is no sol-gel transition temperature observed for PF127+SDS. Using the anionic emission and fluorescence anisotropy value of fisetin, the local polarity and microviscosity in the immediate neighbourhood of fisetin in pluronic-surfactant systems have been estimated. Rotational correlation time along with the time-resolved fluorescence anisotropy study gives additional information about the variation in medium microviscosity (PF127) with temperature in the absence and presence of surfactants. Variation in both polarity and microviscosity of the PF127-surfactant mixed systems follows a reverse trend at sol and gel phases. Fluorescence lifetime studies indicate that fisetin molecules distribute in the different microdomains of PF127-surfactant mixed systems. The local environmental heterogeneity at different microdomains of PF127-surfactant mixed system is confirmed from lifetime distribution analysis of fisetin FT* emission. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

ChemistrySelect

Estimation of Micropolarity and Microviscosity of Pluronic F127–Surfactant Mixed Systems Using Fisetin as a Fluorescent Molecular Probe

Pluronics are polymeric surfactants that undergo sol-gel phase transition as a function of both temperature and concentration and have a high impact on therapeutics. An excited state proton transfer (ESPT) fluorescent molecular probe, 4-chloro-1-naphthol, has been employed to explore the sol-gel transition of pluronics in aqueous media. In aqueous homogeneous media, 4-chloro-1-naphthol shows anionic emission, whereas in heterogeneous media, it results in dual emission of its neutral and anionic forms. Moreover, variations in the intensity (I) ratio, Ineutral/Ianion, and area (A) ratio under the two individual curves, Aneutral/Aanion, faithfully reflect the progressive changes in the medium heterogeneity. The values of both Ineutral/Ianion and Aneutral/Aanion increase with increasing temperature during sol-gel phase transition and reach maxima at the phase transition temperature. Moreover, the higher values of Ineutral/Ianion and Aneutral/Aanion in 10% P123 compared to those in F127 signify a lower micro-polarity of the P123 medium compared to that of F127. Evidence of progressive dehydration is obtained from the excited state decay dynamics. It shows that the proton transfer rate decreases remarkably up to the sol-gel transition temperature and after that it remains almost constant. In the present study, thermo-reversible sol-gel transition of pluronics (P123, F127) along with the dehydration of micelles has been monitored with 4-chloro-1-naphthol. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016.

Fulltext

New Journal of Chemistry

Monitoring thermo-reversible dehydration of the pluronic microenvironment using 4-chloro-1-naphthol as an ESPT fluorescent molecular probe

The photophysical behaviour and excited state decay kinetics of the fluorescent probe Nile red were used for quantitative monitoring of micropolarity, microviscosity and the sol-gel transition temperature of a copolymer hydrogel, pluronic F127. There was considerable enhancement of the emission intensity with a large blue shift in emission and an absorption maximum at and above the sol-gel transition temperature (20 °C), showing the sensitivity of Nile red fluorescence to the sol-gel transition. The estimation of micropolarity by comparing the Nile red emission maximum in dioxane-water mixtures suggested a considerable decrease in the polarity of the PF127 microenvironment from less polar (20% dioxane-water) in its sol phase to almost non-polar (90% dioxane-water) microenvironments in the gel phase. The thermotropic response of the wavelength dependent fluorescence lifetime of the probe with a rise time in the longer wavelength region has enabled monitoring of the microheterogeneity of the gel medium. With an increase in temperature, the microviscosity progressively increases from ∼10 mPa s (sol state) to ∼23 mPa s (gel state). The mismatch between microviscosity as estimated by the Nile red and the corresponding bulk viscosity reflected the microheterogeneity of the pluronic medium and its sensitivity towards PF127 microenvironments. © The Royal Society of Chemistry and Owner Societies.

Photochemical and Photobiological Sciences

Nile red fluorescence for quantitative monitoring of micropolarity and microviscosity of pluronic F127 in aqueous media

Thermotropic microenvironmental changes and the level of hydration in different microenvironments of pluronic F127 (PF127), (PEO<inf>106</inf> PPO<inf>70</inf> PEO<inf>106</inf>, average molar mass 13 000) in aqueous media have been studied using 1-naphthol, which is an ESPT fluorescent molecular probe. The appearance of 1-naphthol neutral form fluorescence in aqueous PF127 (10% w/v) solution indicates the ability of 1-naphthol to sense hydrophobic domains in micellar aggregations. There is a marked enhancement of the neutral form fluorescence at and above the gelation temperature (20°C), which shows that the probe can accurately sense the sol-gel transition. In the temperature range of 10-40°C, with increase in temperature there is a progressive enhancement of the neutral form fluorescence and the blue shift of the neutral and anionic form fluorescence; a decrease in the deprotonation rate constant (k<inf>pt</inf>) indicates that the water-polymer interfacial region is progressively dehydrated. Because k<inf>pt</inf> is related to the availability of proton-accepting water in the microenvironment of 1-naphthol, the reduction of k<inf>pt</inf> indicates progressive dehydration. The thermotropic response of the I<inf>1</inf>/I<inf>3</inf> vibronic band ratio of pyrene-1-butyric acid fluorescence shows a progressive increase in the non-polarity of the interfacial domain with increasing temperature. The increase in non-polarity and the decrease of the hydration level are strongly correlated. This journal is © the Owner Societies.

Physical Chemistry Chemical Physics

1-Naphthol as an ESPT fluorescent molecular probe for sensing thermotropic microenvironmental changes of pluronic F127 in aqueous media

A new fluorescent cholesterol molecular probe, 3-acetyl-7-(diethylamino)-2H-chromen-2-one attached cholesterol (Cum-Chl), has recently been introduced as a reporter of micro-heterogeneous media. The H-aggregate forming ability of Cum-Chl provides a useful fluorescence parameter, Imonomer/Iaggregate to understand the micro-polarity of anisotropic media. Pluronics are surfactant based polymeric anisotropic media having important applications in therapeutics. Being a sensitive indicator of pluronics micro-polarity Imonomer/Iaggregate can help in selecting pluronics for medicinal purposes. Additionally, temperature and concentration induced sol-gel transition of pluronics (P123, F127) have been successfully investigated by Cum-Chl using its Imonomer/Iaggregate value, along with other conventional fluorescence parameters. Finally, this molecular probe, Cum-Chl emerges as a good sensor of progressive polymeric association and micro-polarity of pluronics. © 2015 The Royal Society of Chemistry.

RSC Advances

Utilizing an aggregate forming microenvironment sensitive coumarin-cholesterol conjugate as a sensor of pluronic organization and micro-polarity

The effect of sodium cholate (NaC; concentration 1-16 mM), a biological surfactant, on the aggregation behavior of 1% (w/v, 2.2 × 10-3 M) poly(N-isopropylacrylamide) (PNIPAM) aqueous solutions was studied as a function of temperature. From turbidity, dynamic light scattering, viscosity, and fluorescence measurements, it was observed that (i) there is NaC-induced nanoscale aggregation of PNIPAM in its sol state and (ii) the lower critical solution temperature corresponding to sol-gel transition shifts to a lower temperature by about 2 °C. © 2010 American Chemical Society.

Journal of Physical Chemistry B

Bile-salt-induced aggregation of Poly(N -isopropylacrylamide) and lowering of the lower critical solution temperature in aqueous solutions

European Journal of Pharmaceutics and Biopharmaceutics

Effect of amorphization method on telmisartan solubility and the tableting process

Journal of Pharmacy and Bioallied Sciences

Enhancement of dissolution of Telmisartan through use of solid dispersion technique surface solid dispersion

International Journal of Molecular Sciences

Docetaxel-Loaded Pluronic P123 Polymeric Micelles: in Vitro and in Vivo Evaluation

Biochemical and Biophysical Research Communications

Unique “delta lock” structure of telmisartan is involved in its strongest binding affinity to angiotensin II type 1 receptor

A fluorescence study on the interaction of telmisartan in triblock polymers pluronic P123 and F127

Journal	Data powered by TypesetSpectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Publisher	Data powered by TypesetElsevier
ISSN	13861425
Open Access	No