Título: | DEVELOPMENT OF ANALYTICAL METHODS BASED ON LUMINESCENCE AND ELECTROPHORESIS FOR THE DETERMINATION OF ALKALOIDS (BETA-CARBOLINES, CAMPTOTHECIN AND DERIVATIVES) OF PHARMACOLOGICAL INTEREST | |||||||
Autor: |
FLAVIA FERREIRA DE CARVALHO MARQUES |
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Colaborador(es): |
RICARDO QUEIROZ AUCELIO - Orientador |
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Catalogação: | 14/OUT/2009 | Língua(s): | PORTUGUESE - BRAZIL |
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Tipo: | TEXT | Subtipo: | THESIS | |||||
Notas: |
[pt] Todos os dados constantes dos documentos são de inteira responsabilidade de seus autores. Os dados utilizados nas descrições dos documentos estão em conformidade com os sistemas da administração da PUC-Rio. [en] All data contained in the documents are the sole responsibility of the authors. The data used in the descriptions of the documents are in conformity with the systems of the administration of PUC-Rio. |
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Referência(s): |
[pt] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=14378&idi=1 [en] https://www.maxwell.vrac.puc-rio.br/projetosEspeciais/ETDs/consultas/conteudo.php?strSecao=resultado&nrSeq=14378&idi=2 |
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DOI: | https://doi.org/10.17771/PUCRio.acad.14378 | |||||||
Resumo: | ||||||||
Analytical methods were developed for the selective determination of
alkaloids of pharmacological interest. Aiming the selective determination of
camptothecin (CPT) in irinotecan (CPT-11) or topotecan (TPT) based
pharmaceutical formulations, two spectrofluorimetric methods and one
electrophoretic method with absorciometic detection were proposed. The
spectrofluorimetric method allowed the determination of CPT using the
adjustment of the alkalinity of the sample solution associated with the use of
synchronous scanning or 2nd order spectral derivation. Alternativelly, the
photochemical derivatization (optimized by central composite design) completely
eliminated interferences on the CPT signal. The optimized conditions allowed the
spectrofluorimetric determination of CPT in mixtures containing up to 50 times
more TPT or up to 10 times more CPT-11. The analytical response presented
linear working ranges and homocedasticity. The limit of detection (LD) was in the
order of 10(-10) mol L(-1) for the method based on photochemical derivatization and
one order of magnitude higher for the methods without photochemical
derivatization. Tests were made using TPT and CPT-11 based comercial drugs
and recoveries were around 100%. Such results were comparable to those
obtained with the reference method (HPLC). A study of fluorimetric measurement
uncertainty indicated that the greatest contribution in the process was the
preparation of solution by volume. The contribution from this source was
minimized by the preparation of solutions by weight measurement which caused
a major impact in reducing the expanded uncertainty. The method based on
micellar electrokinetic capillary electrophoresis (MEKC) allowed the simultaneous
quantification of TPT, CPT and CPT-11. To achieve final adjustment of
conditions, an univariated study was made followed by a central composite
design. To improve the sensitivity of detection up to 76 times, a pre-concentration
in the capillary by the normal stacking mode was used along with an extended
optical path cell. The choice of borate buffer (pH 8.5) containing SDS and
acetonitrile implicated in robust conditions of signal and migration times. The
response showed analytical linear working range and homocedasticity, and
9 repeatability of around 3.5%. The LD was in the order of 10(-7) mol L(-1) (TPT) and
10(-8) mol L(-1) (CPT-11 and CPT). Recovery tests using spiked saliva samples were
made and compared with those obtained by a reference method (HPLC) to show
the appropriated accuracy for the proposed method. For the selective
determination of B-carbolines, solid surface room temperature phosphorimetry
(SSRTP) was used. The adjustment of the selective heavy atom and the
application of synchronized scanning technique and 2nd order spectral derivation,
increased the degree of selectivity, because induced phosphorescence of the
analytes of interest in the sample and improved spectral resolution. The
adjustment of the amount of HgCl2 (0.81 mg) allowed the selective determination
of harmol in the presence of up to 10 times higher amounts of harmine, harman,
harmaline and norharman. The method proposed for selective SSRTP
determination of harmol was compared with the results obtained by an adapted
method based on MEKC, which also showed its ability to determine harmol in the
presence of interferences. The absolute limit of detection in the ng order and
linear behavior of the analytical response was obtained. For the analytical
method developed for the determination of harman in the presence of harmine in
teas, optimization studies indicated the following conditions: AgNO3 as the heavy
atom salt deposited on the substrate, sample solution at pH 11 and
measurements made at 322 nm of the 2nd order derivated synchronous scanning
spectrum ((delta)(lambda) = 109 nm). Tests showed that, in optimized conditions, the tea
matrix had no influence on the harman signal and and that harman could be
determined in samples containing harmine in concentrations up to two times
higher. The analytical response showed linear range and homocedasticity. The
repeatability indicated results up to 9.0%. The absolute limit of detection found for
harman was 3.1 ng. In samples of threes different teas, the average recovery of
harman in the presence of harmine was around 100%. The uncertainty of the
SSRTP measurements indicated relevance from the four sources of uncertainty
(repeatability, reproducibility, analytical curve and solutions), which is mostly
caused by the variations in signals produced by non-homogeneities of the solid
substrate used in measurements by SSRTP.
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