A Signal Processing Tool Based on the Continuous Wavelet for the Simultaneous Determination of Estradiol Valerate and Cyproterone Acetate in their Mixtures ERDAL DINÇ1*, FATIH KAS 1, DUMITRU BALEANU2,3,4 1Ankara University, Faculty of Pharmacy, Department of Analytical Chemistry, 06100 Tandogan, Ankara, Turkey 2 Çankaya University, Faculty of Arts and Sciences, Department of Mathematics and Computer Science, 06530 Balgat,Ankara,Turkey 3 Institute of Space Sciences, Magurele-Bucharest, P.O. Box, MG-23, R 76911, Romania 4 Faculty of Engineering,King Abdulaziz University, Department of Chemical and Materials Engineering,P.O. Box: 80204, Jeddah, 21589,Saudi Arabia A signal processing tool based on the continuous wavelet transform (CWT) was proposed for the simultaneousdetermination of estradiol valerate (EV) and cyproterone acetate (CA) in their mixtures. Different continuouswavelet families were tested in order to find the optimum family of the wavelets. The Symlets 8 continuouswavelet transform (SYM8-CWT) was observed to be the optimal one. The SYM8-CWT approach was appliedto the absorption spectra of the related compounds in the spectral range of 210.00-312.35 nm for thecalibration solutions of the compounds in the concentration range of 10-50 µg/mL for EV and 5-30 µg/mL forCA. The calibration equations for EA and CA were computed by measuring the continuous wavelet signals at260.75 nm and 238.40 nm, respectively. The proposed method was validated by the independent analysis ofthe synthetic mixtures and by the standard addition technique. It was observed that the selectivity and thesensitivity in the application of the db5-CWT method to the determination of EV and CA compounds weresatisfactoryKeywords: Continuous wavelet transforms, simultaneous determination, estradiol valerate, cyproteroneacetate, binary mixture
Combination of estradiol valerate (EV) with cyproterone
In this manuscript, a new signal processing method
acetate (CA) is used in hormone replacement therapy
based on the combined use of CWT with zero-crossing
during climacterium. Estradiol valerate and cyproterone
technique was proposed for the simultaneous
acetate are completely absorbed after oral administration.
determination of EV and CA in mixtures and in
During the absorption process and the first liver passage,
commercially formulation. The proposed SYM8-CWT
estradiol valerate but not cyproterone acetate is extensively
method was validated by analyzing the synthetic mixtures
metabolised. Despite complete absorption and ester
of EV and CA and by using the standard addition technique.
hydrolysis of estradiol valerate only 3% of the dose is
Good agreements for the determination results for the
bioavailable as estradiol after oral administration.
Cyproterone acetate is completely bioavailable after oraladministration. During the absorption process and the first
Experimental part
liver passage estradiol valerate is rapidly hydrolysed to
17beta-estradiol and valeric acid. Cyproterone acetate is
mainly metabolised to 15beta-OH cyproterone acetate, a
Wavelet method become ver y powerful in many
pharmacologically active metabolite with similar high
branches of science and engineering [12-13].Wavelet
antiandrogenic but much lower progestogenic activity as
method is devoted to analyze the signal in time-frequency
scale and it is useful in non-stationary signals analysis. In
Ratio derivative spectrophotometric and chemometric
the last decade, the huge potential application of this
methods for the simultaneous quantitative analysis of the
powerful technique in chemistry especially in combination
commercial preparation samples containing EA and CA
to other methods leads us to a conclusion that the wavelet
were recently developed [2]. On the other hand, several
method becomes a powerful technique for the quantitative
analytical methods including spectrophotometry [3-5],
determination of compounds in samples.
HPLC [6,7], fluorimetry [8] and radioimmunoassay [9]
In the following we consider a wavelet family denoted
were devoted for the determination of EV and CA in
by ∅ (λ) [12-13]. By making scaling and shifting of ∅ (λ)
pharmaceutical preparations as well as in the biological
we immediately obtain a set of functions denoted as ∅
liquids. In addition, derivative spectrophotometric method
for determination of estradiol valerate in tablets wasreported [10]. Electrochemical sensor highly selective forestradiol valerate determination based on a modified
carbon paste with iron tetrapyridinoporphyrazine wasdiscussed in [11].
where a represents the scale parameter, b denotes the
Recently, wavelet transform method is a power full tool
translation parameter and R is the domain of real numbers.
for the spectral quantitative analysis of the multi-
Let’s consider a signal f(λ) ∈ L (R), and define the
* email: [email protected]; Tel: +90-0312-215-4886
REV. CHIM. (Bucharest) ♦ 64♦ No. 2 ♦ 2013
LINEAR REGRESSION ANALYSIS AND STATISTICAL RESULTS
Fig. 1. UV absorption spectra of EA (——) and CA (- - - -) in the
range of 10-50 μg/mL and 5-30 μg/mL in methanol
A commercial preparation (CLIMEN® Sugar-coated
tablet, Bayer Schering Pharma, Turkey) was assayed. Itsdeclared content was as follows: 2.0 mg EV and 1.0 mgCA per tablet. CA and EV were donated by the Turkishnational Pharm. Ind. firms, Turkey. Results and discussions
The UV absorption spectra of the standard series and
samples solutions in the concentration range of 10-50 forEV and 5-30 µg/mL for CA were plotted in the wavelengthrange of 210-330 nm (fig. 1). The UV absorption spectradata corresponding to 210.00-312.35 nm were selected
Fig. 2. SYM8-CWT spectra obtained by transformation of the UV
and transferred to the wavelet domain. The obtained
absorption spectra of EA (——) and CA (- - - -) in the range of 10-50
continuous wavelet signals were applied to all wavelet
families available on Wavelet Toolbox in the Matlab 7.0software and the optimal family was retained. As a result
SYM8-CWT (a = 1150) was found to be the optimal CWTtool. The obtained wavelet coefficients were plotted versus
where the superscript * denotes the complex conjugate
wavelengths and then SYM8-CWT spectra were obtained
and 〈ψ (λ), f(λ)〉 means the inner product of function
as shown in figure 2. The analytical CWT amplitudes at
f(λ) onto the wavelet function ψ (λ).
260.75 nm for EV and for CA at 238.40 nm were measured.
Shimadzu UV-2550 UV-Vis double beam spectro-
Calibration graphs were calculated by using the linear
photometer connected to a computer loaded with
regression analysis based on the relationship between their
Shimadzu UVProbe was used for all the spectrophoto-
CWT peak intensity and concentration. The obtained
metric measurements. The absorption data were
calibration graphs and their statistical results from linear
transformed into to the Excel and was processed by SYM8-
regression analysis were presented in table 1. The results
CWT. Wavelet toolbox in Matlab 7.0 was used for the
show high correlation coefficients (r) and satisfactory
slope, intercept, the limit of detection and the limit ofquantitation obtained by the application of the SYM8-CWT
with the selected optimal zero crossing points. This SYM8-
Solutions of 20 mg/100 mL of CA and EV were prepared
CWT method was applied to the simultaneous quantitative
in methanol. The calibration solutions of the compounds
analysis of the samples in the above mentioned optimized
in the concentration range of 10-50 μg/mL for EV and 5-30
μg/mL for CA were prepared by using the above stocksolutions. An independent validation set solutions in the
above concentration ranges were prepared from the stock
The linearity of the calibration graphs obtained by
solutions. The standard addition samples were prepared
applying the SYM8-CWT to the analysis of EV and CA was
by adding stock solution to the commercial samples.
verified by high correlation coefficients (r) as shown intable 1. In recovery studies, the analysis of 19 samples
consisting of the EV-CA combinations in different
In the method application, 20 sugar-coated tablets were
concentration levels was used to test the precision and
accurately weighed and powdered in a mortar. An amount
accuracy of the proposed wavelet methods. The recovery
of the tablet mass corresponding to one tablet content was
results with standard deviation and relative standard
dissolved in 25 of methanol. After 30 min of mechanically
deviations were indicated in table 2. A good coincidence
shaking, the solution was filtered by using a membrane
of the obtained experimental results was observed for the
filter (Sartorius Minisart ϕ = 0.45 μm). The SYM8-CWT
validation of the methods. No degradation product,
method was applied to the final diluted solution.
interference and systematical errors were observed during
REV. CHIM. (Bucharest) ♦ 64 ♦ No. 2 ♦ 2013
DETERMINATION RESULTS OBTAINED APPLYING THE SYM8-CWT
Declarated content of the commercial sugar-coated tablets was asfollows: 2.0 mg EV and 1.0 mg CA per tablet
containing EV and CA. The determination results wereshown in table 3. The experimental results and label claimof tablets showed good coincidence. The numerical datafor the analysis results of related compounds areacceptable determination limits in application of the
Fig. 3. Plots obtained by the SYM8-CWT application to the standard
addition samples of the EA (a) and CA (b) compounds
Conclusions
RECOVERY DATA OBTAINED BY APPLYING SYM8-CWT METHOD TO
In this paper, the wavelet method was applied for the
simultaneous determination of EV and CA in mixtures. Thisapproach was found suitable for the quality control androutine analysis of the pharmaceutical preparationcontaining EA and CA. Acknowledgements : This work was done within the ChemometricLaboratory of Faculty of Pharmacy and it was supported by thescientific research project No. 10A3336001 of Ankara University.References 1.*** http://home.intekom.com/pharm/schering/climan.html 2.DINC E.¸ YUCESOY C., PALABIYIK I.M., USTUNDAG O., ONUR F., 1. J. Pharm. Biomed. Anal. 32(3), 2003, p. 539 3.HONG, Z., LU, B., WANG,C., Hua His I Ko Ta Tsueh Hsueh Pao 22 ,1991, p. 87 (PMID; 1774044), 4.YUCESOY,C., EROL,S., FABAD J. Pharm. Sci. 25 ,2000,p.85 5.YUCESOY,C., EROL, S., J. Fac. Pharm. Ankara, 29 (1), 2000,p. 9 6.YODO, K., SAISHO,S., SHIMOZAWA,K., J. Yata, Endocrinol. Jpn. 4 ,1990, p. 161 7.SCOTT, J.C., SALTERO,R.A., J. Chromatogr. Sci. 25 ,1987, p. 415 8.JAMES,T., J. Assoc. Off. Anal. Chem. 56 ,1973, p. 86 9.BAUMANN, A., KULMANN,H., GORKOV, V., M. MAHLER, M., KHUNZ,
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excipients on the analysis of commercial samples. The
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Quantitative analysis was carried out by applying the
SYM8-CWT method to the commercial preparation
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