Evidence for the Formation of a Benzo[a]phenothiazine/2-Hydroxypropyl-β-Cyclodextrin Inclusion Complex Using a Fluorescence Method*

Abstract

The inclusion complex of benzo[ a]-12H-phenothiazine (BPHT) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) was investigated in an aqueous solution containing 1% ethanol. It was found that the fluorescence emission intensity of the complexed fluorophore is six times larger than that of un complexed species and 1.5 times higher than that in pure ethanol. BPHT forms a 1:1 complex when included in the HP-β-CD. An association constant of the complex of 100±20 M−1 was calculated by using the Benesi–Hildebrand treatment of fluorescence emission data. A discussion based on AM1 semiempirical calculation of BPHT geometry indicates that the inclusion of BPHT in HP-β-CD is partially achieved, probably by the hydrophobic aromatic moiety of the molecule.

Usefulness of cyclodextrins for detection in molecular fluorescence. Application to xenobiotics and drugs

“…Once more, it should be pointed out that these elegant spectroscopic [9][10] studies were fundamentally conducted with the aim of getting a better insight in the host-guest interaction but without any analytical application purpose. The fluorescence probe acted in such a system only as a "molecular spy" to elucidate the supramolecular interactions involved between various cyclodextrins derivatives and guest organic species.…”

Luminescence in organized media and supramolecular interactions:physicochemical aspects and applications

“…The photoprotection offered to promazine in aqueous solution in the presence of CDs has been analysed by Lutka [6]. Maafi et al looked at a 2-hydroxypropyl-β-cyclodextrin:benzo[a]phenothiazine inclusion complex and noted a 12-fold increase in fluorescence intensity relative to the free analyte [131,132]. The authors have used this feature to develop the first spectrofluorimetric determination of this anticancerous drug in the presence of cyclodextrins.…”

Bioactive Phenothiazines and Benzo[a]phenothiazines: Spectroscopic Studies, and Biological and Biomedical Properties and Applications

“…More recently, in the 1980s and 1990s new series of fused phenothiazine derivatives, the benzo[a, b or c]phenothiazines (BPHTs), were synthesized [3, 21 and references therein] and have received a great deal of attention, mainly because of their potential applications and their important biomedical properties [12][13][14][15][16][17][18][19][20][21][22][23][24]. Indeed, some BPHTs are coloured compounds and have been applied as polycyclic dyes or pigments for synthetic polymers, and also in optical recording media ( [21] and references therein).…”

“…Indeed, some BPHTs are coloured compounds and have been applied as polycyclic dyes or pigments for synthetic polymers, and also in optical recording media ( [21] and references therein). Moreover, certain benzo[a or c]phenothiazine derivatives are potential antihelmintics, possess an antiviral activity, for example inhibiting the multiplication of encephalomyocarditis viruses in tissue cultures ( [21,22], and refer- [13][14][15]. Also, benzo[a]phenothiazines and their hydro derivatives were shown to be strong leukotriene inhibitors, useful in the treatment of allergic inflammatory and cardiovascular conditions ( [21] and references therein).…”

“…Moreover, certain benzo[a or c]phenothiazine derivatives are potential antihelmintics, possess an antiviral activity, for example inhibiting the multiplication of encephalomyocarditis viruses in tissue cultures ( [21,22], and refer- [13][14][15]. Also, benzo[a]phenothiazines and their hydro derivatives were shown to be strong leukotriene inhibitors, useful in the treatment of allergic inflammatory and cardiovascular conditions ( [21] and references therein). Therefore, as already mentioned, BPHTs, and particularly benzo[a]phenothiazines (Fig.…”