Combinatorial
Chemistry & High Throughput Screening
ISSN: 1386-2073
Combinatorial Chemistry
& High Throughput Screening
Volume 13, Number 8, September 2010
Contents
Present Applications of Analytical Methods: Prospects
for High Throughput Screening of Pharmaceutically Active Compounds
(Part 3)
Guest Editor: Sibel A. Ozkan
Editorial Pp. 665
Original Research Articles
Development and Application of a Highly Selective
Biomimetic Sensor for Detection of Captopril, an Important
Ally in Hypertension Control Pp. 666-674
Ademar Wong, Marcos R.V. Lanza and Maria D.P.T.
Sotomayor
[Abstract] [Purchase
Article]
Colorimetric and Atomic Absorption Spectrometric Determination
of Mucolytic Drug Ambroxol Through Ion-Pair Formation with
Iron and Thiocyanate Pp. 675-682
Abdulkadir Levent and Zühre Sentürk
[Abstract] [Purchase
Article]
The Development and In Vitro Evaluation of Sustained
Release Tablet Formulations of Benzydamine Hydrochloride and
its Determination Pp. 683-689
Cansel Kose-Ozkan, Ayhan Savaser, Cetin Tas and
Yalcin Ozkan
[Abstract] [Purchase
Article]
Enantioanalysis of (-)Butaclamol Using Vancomycin and Teicoplanin
as Chiral Selectors Pp. 690-693
Raluca-Ioana Stefan van Staden, Nontete Suzan
Nhlapo, Jacobus Frederick van Staden and Hassan Y.
Aboul-Enein
[Abstract] [Purchase
Article]
Anodic Voltammetric Behavior and Determination of
Rosiglitazone in Pharmaceutical Dosage Forms and Biological
Fluids on Solid Electrode Pp. 694-702
Burcu Dogan-Topal, Secil Tuncel and Sibel A.
Ozkan
[Abstract] [Purchase
Article]
The Natural Diatomite from Çaldiran-Van (Turkey):
Electroanalytical Application to Antimigraine Compound Naratriptan
at Modified Carbon Paste Electrode Pp. 703-711
Necla Çaliskan, Eda Sögüt, Cafer Saka,
Yavuz Yardim and Zühre Sentürk
[Abstract] [Purchase
Article]
Review Articles
Stability and Drug Metabolism Assessed by Electrochemical
Methods Pp. 712-727
Alejandro Álvarez-Lueje and Soledad Bollo
Dragnic
[Abstract] [Purchase
Article]
Recent Updates of Chemically Modified Electrodes in
Pharmaceutical Analysis Pp. 728-752
Abd-Elgawad Radi
[Abstract] [Purchase
Article]
Analysis of Organic Compounds Using an In Situ Plated
Lead Film Electrode Pp.753-757
Katarzyna Tyszczuk and Mieczyslaw Korolczuk
[Abstract]
[Purchase Article]
Application of Adsorptive Stripping Voltammetry for
the Determination of Selected Methoxyimino Cephalosporins
in Urine Samples Pp. 756-763
Mara M. Aleksic and Vera Kapetanovic
[Abstract] [Purchase
Article]
Meet
the Guest Editor Pp. 764
Abstracts
[Back to top]
Editorial
Analytical chemistry is one of the oldest scientific
disciplines. The development of chemistry itself has progressed
significantly by analytical findings over several centuries.
In recent times, analytical chemistry has stimulated not only
chemistry but many fields of science, technology and society.
Conversely, analytical chemistry itself has always been heavily
influenced by fields like environmental protection, biology,
and medicine. Analytical chemistry in the new millennium will
continue to develop greater degrees of sophistication. The
use of automation system for routine work will increase and
the role of ever more powerful computers and software, such
as ‘intelligent’ expert systems, will be a dominant
factor.
Pharmaceutical Sciences have contributed to drug development,
synthesis, formulations and analysis through extensive studies
in drug assays. Analytical chemists and pharmaceutical scientists
play important roles in monitoring the drugs in their dosage
forms and biological samples. The sensitivity of the analytical
assay has a direct impact on the validity of the pharmacokinetic
model which is built up from plasma concentration data. The
precision and accuracy of the assay is also important, and
it is not always straightforwardly estimated. Analytical methods
widely utilize the knowledge of all the other disciplines
such as biology, pharmaceutical chemistry, pharmaceutical
technology, biotechnology and many other fields. A new significant
parameter is the speed of analysis, and the resulting massive
production of analytical data. From the viewpoints mentioned
above, the title of this special issue, “Applications
of Analytical Methods: Prospects for High Throughput Screening
of Pharmaceutically Active Compounds”,
was chosen so as to ask analytical chemists and pharmaceutical
scientists to appreciate their great roles in pharmaceutical
science. The third part of this special issue feature 4
Reviews and 6 Original Papers. Recent developments
of separation techniques such as liquid chromatography, high
throughput screening methodologies and spectrophotometric
methods and their biological and pharmaceutical applications
are presented. The third issue represents all important sensors,
analytical, electroanalytical and separation methods. In the
last issue, chromatographic, electroanalytical, sensor, atomic,
spectroscopic and colorimetric techniques and their applications
were reported. The purpose of this special issue will be to
serve as a guide to what analytical methods bring to analytical
and medicinal chemistry and other pharmaceutical sciences
as well as briefly review their role in drugs and the new
developments and validation of assay methods of pharmaceutically
active compounds. This special issue is multidisciplinary.
Also recent developments of application, evaluation and validation
of analytical methods are focused by key topics in drug developments
and analysis by assessment of the distinguished authors of
this special issue.
New drugs coming from biotechnology, and their dosage forms,
like targeted drugs, may produce new analytical problems in
the future. The various analytical methods that permit the
determination of drugs in their dosage forms, raw material,
biological media etc, and also their metabolites to be separated,
identified and quantitatively assayed are briefly reviewed.
The current significance of separation, electrochemical, spectrophotometric
and other methods is highlighted, as well as the limits of
trace assays. In addition to other analytical methods, the
use of electrochemical methods to gain key information about
drug molecules and their mechanism of action is getting one
of the important ways in drug discovery. Applications of electrochemical
techniques to redox-active drug development and mechanistic
studies are one of the recent interests in drug discovery.
Thus, I expect this special issue will assist readers to find
out new information and to encourage them to contribute more
to recent development on drug development and its analysis
using different methods. I would like to thank to all of the
authors for their excellent contributions, and the Editor-in-Chief
of Combinatorial Chemistry & High Throughput Screening
for his kind invitation to act as guest editor for this special
issue.
Sibel A. Ozkan
(Guest Editor)
Faculty of Pharmacy
Department of Analytical Chemistry
Ankara University
06100, Tandogan
Ankara
Turkey
E-mails: ozkan@pharmacy.ankara.edu.tr,
sibelaysil@gmail.com
[Back to top]
[Purchase Article]
Development and Application of a Highly Selective Biomimetic
Sensor for Detection of Captopril, an Important Ally in Hypertension
Control
Ademar Wong, Marcos R.V. Lanza and Maria D.P.T.
Sotomayor
A biomimetic sensor is proposed as a promising new analytical
method for determination of captopril in different classes
of samples. The sensor was prepared by modifying a carbon
paste electrode with iron (II) phthalocyanine bis(pyridine)
[FePc(dipy)] complex. Amperometric measurements in a batch
analytical mode were first carried out in order to optimize
the sensor response. An applied potential lower than 0.2 V
vs Ag|AgCl in 0.1 mol L-1
of TRIS buffer at pH 8.0 provided the best response, with
a linear range of 2.5 x 10-5
to 1.7 x 10-4 mol L-1.
A detailed investigation of the selectivity of the sensor,
employing seventeen other drugs, was also performed. Recovery
studies were carried out using biological and environment
samples in order to evaluate the sensor’s potential
for use with these sample classes. Finally, the performance
of the biomimetic sensor was optimized in a flow injection
(FIA) system using a wall jet electrochemical cell. Under
optimized flow conditions, a broad linear response range,
from 5.0 x 10-4 to 2.5 x
10-2 mol L-1,
was obtained for captopril, with a sensitivity of 210 ±
1 μA
L mol-1.
[Back to top] [Purchase
Article]
Colorimetric and Atomic Absorption Spectrometric Determination
of Mucolytic Drug Ambroxol Through Ion-Pair Formation with
Iron and Thiocyanate
Abdulkadir Levent and Zühre Sentürk
Colorimetric and atomic absorption spectrometric methods
have been developed for the determination of mucolytic drug
Ambroxol. These procedures depend upon the reaction of iron(III)
metal ion with the drug in the presence of thiocyanate ion
to form stable ion-pair complex which is extractable in chloroform.
The red-colored complex was determined either colorimetrically
at 510 nm or by indirect atomic absorption spectrometry (AAS)
via the determination of the iron content in the formed complex.
The optimum experimental conditions for pH, concentrations
of Fe3+ and SCN, shaking
time, phase ratio, and the number of extractions were determined.
Under the proposed conditions, linearity was obeyed in the
concentration ranges 4.1x10-6–
5.7x10-5 M (1.7-23.6 μg
mL-1) using both methods,
with detection limits of 4.6x10-7
M (0.19 μg
mL-1) for colorimetry and
1.1x10-6 M (0.46 μg
mL-1) for AAS. The proposed
methods were applied for the determination of Ambroxol in
tablet dosage forms. The results obtained were statistically
analyzed and compared with those obtained by applying the
high-performance liquid chromatographic method with diode-array
detection.
[Back to top] [Purchase
Article]
The Development and In Vitro Evaluation of Sustained
Release Tablet Formulations of Benzydamine Hydrochloride and
its Determination
Cansel Kose-Ozkan, Ayhan Savaser, Cetin Tas
and Yalcin Ozkan
A novel oral controlled delivery system for benzydamine hydrochloride
(BN) was developed and optimized. Hydrophilic matrix tablets
of BN were prepared by using hydroxypropylmethylcellulose
(HPMC) and chitosan as polymer substance to achieve required
sustained release profile. The matrix tablets were prepared
by both direct compression and wet granulation method. The
influence of matrix forming agents and binary mixtures of
them on BN release was investigated. The formulated tablets
were characterized by hardness, friability, thickness, weight
variation and in vitro drug release. The formulated
tablets had acceptable physicochemical characters. The quantity
of BN present in the tablets and the release medium were estimated
by a simple, sensitive, rapid and validated HPLC method. The
dissolution results show that increased amount of polymer
resulted in reduced and extended drug release. F7 formulation
containing 12.5% HPMC and 12.5% chitosan with direct compression
method is the optimum formulation due to its better targeting
profile in terms of release. Higuchi (diffusion) and Hixon-Crowell
(erosion) kinetic profiles were achieved and this codependent
mechanism of drug release was established. This formulation
may provide an alternative for oral controlled delivery of
BN and be helpful in the future treatment of primary normoreactive
types of inflammation.
[Back to top] [Purchase
Article]
Enantioanalysis of (-)Butaclamol Using Vancomycin and Teicoplanin
as Chiral Selectors
Raluca-Ioana Stefan van Staden, Nontete Suzan
Nhlapo, Jacobus Frederick van Staden and Hassan Y.
Aboul-Enein
Butaclamol is an antipsychotic drug used in the treatment
of schizophrenia. The macrocyclic antibiotics, vancomycin
and teicoplanin, are proposed as chiral selectors for the
design of enantioselective, potentiometric membrane electrodes
(EPMEs) for the assay of (-)butaclamol. The slopes of the
electrodes are near-Nernstian for the assay of (-) butaclamol
with linear concentration ranges between 10-7
and 10-10 mol/L and between
10-9 and 10-7
mol/L for vancomycin and teicoplanin based EPMEs. Limits of
detections varied. The electrodes were used reliably for the
enantioanalysis of (-) butaclamol in serum samples.
[Back to top] [Purchase
Article]
Anodic Voltammetric Behavior and Determination of
Rosiglitazone in Pharmaceutical Dosage Forms and Biological
Fluids on Solid Electrode
Burcu Dogan-Topal, Secil Tuncel and Sibel A.
Ozkan
The anodic voltammetric behavior and electroanalytical determination
of rosiglitazone were studied using cyclic, linear sweep,
differential pulse and square wave voltammetric techniques
on a glassy carbon electrode. The oxidation of rosiglitazone
was irreversible and exhibited diffusion controlled process
depending on pH. Different parameters were tested to optimize
the conditions for the determination of the oxidation mechanism
of rosiglitazone. The dependence of current intensities and
potentials on pH, concentration, scan rate, nature of the
buffer was also investigated. According to the linear relationship
between the peak current and the concentration, differential
pulse and square wave voltammetric methods for rosiglitazone
assay in pharmaceutical dosage forms and biological fluids
were developed. A linear response was obtained within the
range of 1x10-6M - 6x10-5M
in 0.1 M H22SO4
and acetate buffer at pH 5.70 for both voltammetric methods
in human serum samples. The practical analytical value of
the method was demonstrated by quantitative determination
of rosiglitazon in pharmaceutical formulation and human serum,
without the need for separation or complex sample preparation,
since there was no interference from the excipients and endogenous
substances. The methods were fully validated and successfully
applied to the high throughput determination of the drug in
tablets and human serum with good recoveries.
[Back to top] [Purchase
Article]
The Natural Diatomite from Çaldiran-Van
(Turkey): Electroanalytical Application to Antimigraine Compound
Naratriptan at Modified Carbon Paste Electrode
Necla Çaliskan, Eda Sögüt, Cafer Saka,
Yavuz Yardim and Zühre Sentürk
This paper is the first report describing the characterization
of local diatomite of Çaldiran-Van region (Eastern
Anatolia, Turkey). Special attention was paid to the ability
of its electroanalytical performance at modified electrodes
and to the potential application of diatomite-modified electrode.
For this purpose, the determination of Naratriptan which is
a novel oral triptan (5-hydroxytryptamine receptor agonist)
in migraine treatment, by means of a carbon paste electrode
modified with 10% (w/w) of diatomite was studied using cyclic
and square-wave voltammetry. The experimental conditions that
affect the electrode reaction process were studied in terms
of pH of the supporting electrolyte, scan rate, accumulation
variables, modifier composition and square-wave parameters.
Using square-wave stripping mode, the drug yielded a well-defined
voltammetric response in Britton-Robinson buffer, pH 4.0 at
0.84 V (vs Ag/AgCl) (a pre-concentration step being
carried out with an open circuit at 120 s). The process could
be used to determine Naratriptan concentrations in the range
5x10-7 9x10-7
M, with a detection limit of 1.25x10-7
M (46.5 μg
L-1). The applicability of
the method to spiked human urine samples was illustrated.
[Back to top]
[Purchase
Article]
Stability and Drug Metabolism Assessed by Electrochemical
Methods
Alejandro Álvarez-Lueje and Soledad Bollo
Dragnic
This review is focused on the use of the electrochemical
techniques, voltammetry and polarography, as well as biosensors,
for the study of drug stability. In addition, this review
also details the study of drug metabolism by electrochemistry
and mass spectrometry. This is used as a tool to mimic drug
metabolism and because it is a purely instrumental method,
may have advantages over, or be complementary to, the existing
biological assays.
[Back to top] [Purchase
Article]
Recent Updates of Chemically Modified Electrodes in
Pharmaceutical Analysis
Abd-Elgawad Radi
This review article has gathered different types of electrode
modification with a brief introduction given to explain several
phenomena occurring at chemically modified electrodes and
the mechanism of detection, followed by some interesting applications
of chemically modified electrodes (CMEs) in pharmaceutical
analysis, emphasizing on the biosensors and CNT-based chemical
sensors.
[Back to top]
[Purchase Article]
Analysis of Organic Compounds Using an In Situ Plated
Lead Film Electrode
Katarzyna Tyszczuk and Mieczyslaw Korolczuk
For many years mercury electrodes were commonly used in stripping
voltammetry for determination of organic compounds, owing
to their high sensitivity, reproducibility and renewability.
However, because of the toxicity of mercury, alternative (less
toxic) electrode materials are searched. The review describes
recent results regarding adsorptive stripping voltammetric
determination of trace concentration of biologically active
organic substances using an in situ plated lead film
electrode (LFE). Such an electrode exhibits the distinct advantage
of simple preparation, good reproducibility and electrochemical
surface renewal. The article reviews the development, behavior
and application of a lead film electrode for stripping voltammetry
of biologically active organic compounds.
[Back to top]
[Purchase
Article]
Application of Adsorptive Stripping Voltammetry for
the Determination of Selected Methoxyimino Cephalosporins
in Urine Samples
Mara M. Aleksic and Vera Kapetanovic
In the last two decades different electroanalytical methods
were used for sensitive and selective determination of cephalosporins.
The paper was focused on the electrochemical behavior of methoxyimino
cephalosporins, reduction mechanism and nature of the process
at the mercury electrode surface. Special attention was paid
to the cephalosporins adsorption at the mercury surface. Based
on this phenomenon, the adsorptive stripping methods were
established for determination of the low concentration of
these drugs in urine samples, both in vitro, and
in vivo conditions. The application of Adsorptive
Stripping Differential Pulse Voltammetry (AdSDPV) for the
determination of cefpodoxime proxetil (CP), cefotaxime (CF),
desacetylcefotaxime (DCF) and cefetamet (CEF) was summarized.
The best sensitivity of in vitro determination in
urine was achieved for CP, in acid solutions (LOD 7.4×10-9M
and LOQ 2.4×10-8M),
followed by CF, CEF and DCF. This is in accordance with the
strength of their adsorption. Determination of CF and DCF
by AdSDPV in vivo was also presented. Compared to
other analytical methods, AdSDPV showed advantages in the
simplicity of sample preparation, and over the other voltamperometric
methods, higher sensitivity and selectivity.
|
