Investigation of physico-chemical behaviour of local anaesthetics in aqueous SDS solutions

Fluorescence study of tetracaine–cyclodextrin inclusion complexes

“…The corresponding values have been determined by potentiometry at 0.10 M ionic strength NaCl. The results are reported in Table 2 along with the values determined from the spectroscopic titration method 26 and from literature data. 27 Therefore, three different absorbing species of tetracaine can be considered on varying the pH of the medium, which correspond to TcH 2…”

“…As the pH regions in fluorescence are similar to those observed in the ground state, it suggest no significant changes on the pK a value of TCA in the excited state in accordance with the Fırster approximation. 26,28 In addition, at pH>4 (existence of TcH + or Tc) dual fluorescence is observed. The emitting chromophore in tetracaine is the benzene ring, and emission occurs from both the lowest (π, π*) singlet state (LE) and the intramolecular charge transfer (ICT) state, which is originated from the N-lone pair of the secondary amine group (acting as the electron donor group) to π-orbitals of the benzene ring or to the carbonyl group that is characterized by a high electron accepting character.…”

Exploring the effect of supramolecular structures of micelles and cyclodextrins on fluorescence emission of local anesthetics

“…9- 13 In previous works we have studied the interactions of some local anesthetics, including novocaine, tetracaine and procainamide, with closed environments of micelles and cylodextrins under different experimental conditions. [14][15][16] The common characteristic of these LA is that the amine group is in the para-position with respect to the ester (or amide) group. We have found that the most appropriate experimental conditions that yield the highest interaction between the cyclodextrin and the LA correspond to both neutral LA and cyclodextrin, that is, when the van der Waals interactions and the hydrophobic effect that excludes the LA from the bulk water phase reach the maximum level.…”

Effect of surfactant head group on micellization and morphological transitions in drug-Surfactant catanionic mixture: A multi-technique approach

“…Once cac reached, the sharp increase in intensity has been observed with remarkable change in λmax, indicating that TC molecules strongly bind with micellar surface having low dielectric constant than water which eventually enhance the quantum yield of the fluorophore [47]. Once the cmc of surfactant reached the fluorescence intensity of TC gets saturated with constant λmax.…”