DETERMINATION OF SERTINDOLE IN BLOOD BY FLUORESCENCE SPECTROSCOPY

Abstract

Introduction. Since their introduction in 1952, antipsychotic drugs are the primary and most effective intervention for the treatment of acute psychosis and the prevention of relapse in patients with schizophrenia.

Sertindole, 1-[2-[4-[5-chloro-1-(4-fluorophenyl)-1H-indol-3-yl]-1-piperidinyl] ethyl]-2-imidazolodinone, is an atypical antipsychotic drug introduced on the market in 1996. Sertindole is a serotonin 5-HT2A and 5-HT2C, dopamine D2 and α1-adrenergic antagonist. Despite the progress in the treatment of mental illness, treatment with this antipsychotics remedy is still associated with toxic and lethal consequences. Analysis of published data showed a few analytical methods for quantification of sertindole in plasma by HPLC with UV and tandem mass-spectrometric detection. For this reason, development of express methods for its determination in human blood is an urgent task in the laboratory and toxicological studies.

Aim of investigation was to develop a simple, accurate and sensitive method for determination of sertindole in human blood grounded on its fluorescent properties.

Investigation methods. Measurements of sertindole natural fluorescence intensity were performed on spectrofluorometer Hitachi MPF4 (Japan). It was measured in three polar solvents (96 % ethanol, isopropanol and acetonitrile).

Stock solutions of sertindole for generating calibration curves, were prepared in 96 % ethanol to yield concentrations of 1 mg/ml. Sertindole was HPLC grade from Sigma-Aldrich (USA).

Model samples were prepared on 5-ml blood probes adding on 0.05; 0.25; 0.5; 1.25; 2.5; and 5.0 mg of sertindole and on 5 ml of purified water.

Samples shake 2 min to homogenous mass. To investigated samples add 5 ml of 20 % oxalic acid solution and ultrasonically treat at 52 kHz. After that, we centrifuge the blood sample in a tube for 15 minutes (10000 RPM). Supernantants were separated. The residues were treated with 2 ml of 20 % oxalic acid solution ones more and centrifuged. Supernatants were united and adjusted by 30 % sodium hydroxide solution to to pH 11 (universal indicator). Preparation was extracted by 1, 2 – dichloroethane twice. Dichloroethane extracts were combined, solvent evaporated to dryness at 40°С. The dry residue was quantitatively dissolved in 5 ml of 96% ethanol and then we measured its native fluorescence under developed conditions.

Results and discussion. Fluorescence spectra of sertindole molecules in 96% ethanol are characterized excitation at 310 nm and emission at 345 nm. Fluorescence intensity is more in isopropanol solution; but control blood probes demonstrate matrix effect, which decrease sensibility. For a sertindole determination would prefer ethanol solutions.

Calibration curve was linear over a sertindole concentration range from 10 to 1000 ng/ml. It is described by the equation , where Y is the intensity of fluorescence emission, and X is the concentration of sertindole (ng/ml). Relative error of sertindole quantification is 0.98% in 96% ethanol.

In extracts from the blood were determined up to 87% sertindole. The lower limit of quantification in blood is 12 ng/ml. Relative error of sertindole quantification in blood is 2.41%.

Conclusions. Conditions of sertindole isolation and identification in biological fluids on model mixes with blood are studied. Experimentally proved the feasibility of fluorometry developed techniques to quantify sertindole in extracts from biological fluids in forensic and toxicological investigations.

The proposed method spectrofluorimetric method for determination of sertindole in human blood has high stability and sensitivity. This technique can be used to determine the therapeutic and toxic levels of sertindole concentrations in blood during laboratory and toxicological studies.