|
Current Pharmaceutical
Analysis
ISSN: 1573-4129
Current Pharmaceutical
Analysis
Volume 2, Number 2, May 2006
Contents
Solid-Phase Extraction (SPE) Techniques for Sample
Preparation in Clinical and Pharmaceutical Analysis: A Brief
Overview Pp. 95-102
Kong M. Li, Laurent P. Rivory and Stephen J.
Clarke
[Abstract]
HPLC Analysis of Human Pituitary Hormones for Pharmaceutical
Applications Pp. 103-126
Maria Teresa C.P. Ribela, Peter W. Gout, João
Ezequiel de Oliveira and Paolo Bartolini
[Abstract]
Multicomponent Determination of Drugs Using Flow-Injection
Analysis Pp. 127-140
Leah Hlabangana, Santiago Hernández-Cassou
and Javier Saurina
[Abstract]
Electron Paramagnetic Resonance (EPR) Spectroscopy: A Versatile
and Powerful Tool in Pharmaceutical and Biomedical Analysis
Pp. 141-159
Marina Carini, Giancarlo Aldini, Marica Orioli and
Roberto Maffei Facino
[Abstract]
Effects of Statins on Bone Markers, Bone Mineral Density
and Fractures. Possible Role in Osteoporosis Treatment Pp.
161-168
José L. Pérez-Castrillón,
Laura Abad, Gema Vega, Alberto Sanz Cantalapiedra Santiago
Sanchez, Gonzalo Hernandez and Antonio Dueñas
[Abstract]
Biosynthesis, Signal Transduction and Molecular Regulation
of Cytokinins Pp. 169-182
Yu Ding and Qing-Hu Ma
[Abstract]
Recent Advances in the Analyses of Phytoestrogens
and Their Role in Human Health Pp. 183-193
M. Humayoun Akhtar and E-S. M. Abdel-Aal
[Abstract]
Recent Advances in the Analyses of Carotenoids and Their
Role in Human Health Pp. 195-205
E-S. M. Abdel-Aal and M. Humayoun Akhtar
[Abstract]
Abstracts
[Back to top]
Solid-Phase Extraction (SPE) Techniques for Sample
Preparation in Clinical and Pharmaceutical Analysis: A Brief
Overview
Kong M. Li, Laurent P. Rivory and Stephen J.
Clarke
Quantitation of low concentration of
drugs, metabolites and endogenous compounds in plasma has
always been a difficulty and challenge task for analytical
chemists in biomedical and pharmaceutical analysis. It often
requires extracting and concentrating the analytes in the
samples for quantitative analysis. Extraction from the plasma
matrix potentially enables the simultaneous removal of endogenous
interfering substances and the enrichment of the analytes.
However, extraction procedures are frequently the most time
consuming steps of the analytical process. Lack of robustness
of the extraction procedure is a common problem leading to
the invalidation of entire analytic runs. Solid-Phase Extraction
(SPE) is a powerful sample preparation technique currently
available for rapid clean-up and enrichment of sample analytes
preceding chromatographic analysis. Compared to traditional
liquid-liquid extraction (LLE), SPE provides major advantages
in terms of simplicity, high throughput, robustness, and in
most cases, greater cost effectiveness. A wide range of SPE
resin chemistries is now available for various applications.
The sampling format has also extended from simple packed disposable
syringes to cartridges, disks, SPE pipette tips, 96-well and
384-well micro-plates. Therefore, SPE sample preparation techniques
provide improved assay standardisation and hence better reproducibility.
The objective of this article was to review literatures regarding
SPE extraction theory, extraction modes and its application
in clinical and pharmaceutical analysis. Updated information
about the most important features of the SPE materials and
the future trends in SPE sample preparation are also discussed.
[Back to top]
HPLC Analysis of Human Pituitary Hormones for Pharmaceutical
Applications
Maria Teresa C.P. Ribela, Peter W. Gout, João
Ezequiel de Oliveira and Paolo Bartolini
The advent of recombinant DNA technologies
in the last two decades has made it possible to synthesize
practically unlimited amounts of human proteins for therapeutic
usage. This synthetic approach has been particularly valuable
in the case of the pituitary hormones, growth hormone, prolactin,
thyrotropin, luteinizing hormone and follicle-stimulating
hormone, which have important diagnostic and therapeutic applications.
To determine the identity, purity, potency, safety and stability
of these synthetic proteins, a variety of analytical techniques
have been recommended, which are mostly based on physico-chemical
properties of the proteins. Among these techniques High Performance
Liquid Chromatography (HPLC), exploiting differences in protein
properties such as size, hydrophobicity and charge, has become
increasingly useful. Its accuracy, sensitivity, resolving
power, speed and versatility have not only been established
in research, but also in the quality and process control of
industrial protein synthesis. In the case of biologically
active proteins such as hormones, it has become more and more
evident that HPLC is now strongly complementing, if not substituting,
the classical biological and immunological assays whose accuracy
limitations are well known. Moreover, it has been shown that
the potential for early detection of impurities and molecular
alterations provided by this technique allows more efficient
and effective control both at the beginning and along the
manufacturing process, leading to improved and more economical
end products. This review article describes and analyzes recent
developments of the main HPLC modalities, applied in the analysis
and characterization of the above mentioned hormones, especially
as they are relevant to the biopharmaceutical industry.
[Back to top]
Multicomponent Determination of Drugs Using Flow-Injection
Analysis
Leah Hlabangana, Santiago Hernández-Cassou
and Javier Saurina
This paper reviews the principal strategies
for multicomponent determinations of pharmaceutical products
and related compounds using flow-injection analysis (FIA).
The relevancy of this topic in the pharmaceutical field and
close areas such as clinical, food and biochemical analysis
is pointed out. As an alternative to chromatographic and electrophoretic
methods, multicomponent FIA is specially suitable for a rapid
quantification of analytes and processing large sets of samples.
The achievement of selective measurement conditions to carry
out the quantification of each drug without interferences
is commonly needed in multicomponent analysis. The main approaches
for gaining selectivity are based on specific reagents, multi-way
or fast-scanning detectors, serial and parallel multi-channel
manifolds. Alternatively, chemometric methods for data analysis
can be used when selectivity is not fully accomplished.
[Back to top]
Electron Paramagnetic Resonance (EPR) Spectroscopy: A Versatile
and Powerful Tool in Pharmaceutical and Biomedical Analysis
Marina Carini, Giancarlo Aldini, Marica Orioli and
Roberto Maffei Facino
The aim of this paper is to provide an overview on Electron
Paramagnetic Resonance (EPR) spectroscopy [or equivalently
Electron Spin Resonance (ESR)], indicating the areas of consolidated
and potential applications in the pharmaceutical, biomedical
and clinical fields, and the instrumental and conceptual developments
that are involved. The unique capability of EPR to detect
and characterise free radicals and other species with unpaired
electrons has been successfully applied to measure both in
vitro and in vivo free radical intermediates
from drugs and oxidative processes, to study the free radical/antioxidant
properties of drugs, to study drug-membrane interactions or
to monitor pharmaceuticals radio sterilisation. Although EPR
has been mainly devoted in the past to qualitative analysis,
following development of software and high-sensitivity instrumentation,
applications of the technique have been extended more recently
to the quantitative analysis. The potential value of in
vivo EPR includes: drug detection in body fluids, pharmacokinetic
and metabolism studies, direct detection or measurement of
free radicals (especially nitric oxide, the critical physiological
mediator of vascular homeostasis and cardiac function). In
addition, because EPR almost uniquely can make repeated and
accurate measurements of pO2
in tissues, another interesting area in the pharmaceutical
field is oximetry (now emerging also for clinical use), and
some examples of its application in drug/formulation development,
and in preclinical studies are reported.
[Back to top]
Effects of Statins on Bone Markers, Bone Mineral Density
and Fractures. Possible Role in Osteoporosis Treatment
José L. Pérez-Castrillón,
Laura Abad, Gema Vega, Alberto Sanz Cantalapiedra Santiago
Sanchez, Gonzalo Hernandez and Antonio Dueñas
Several clinical trials have shown an association between
osteoporosis and an increase in cardiovascular mortality,
especially in patients with vertebral fracture. In addition
to their action on a decrease in cholesterol levels and a
reduction of mortality in individuals with ischemic heart
disease, statins can have a beneficial effect on other chronic
diseases, including osteoporosis.
Statins can have anabolic and anticatabolic effects on bone.
Mundy published the first in vitro study with animals
and demonstrated an anabolic effect of the statins on bone.
On the other hand, through its action on the 3-hydroxy-3-methylglutarylcoenzyme
A (HMG-CoA) reductase, it inhibits the mevalonate synthesis
by reducing the prenylation of glutamyltranspeptidase (Ras,
Rho, Rai, Rab) necessary to osteoclast activity and the decrease
in the apoptosis, which results in a decrease in bone resorption.
Studies on humans have alnalyzed the effect of statins on
bone remodeling markers, bone mass fracture risks. Retrospective
studies (case-control, cohort studies) followed, which showed
a beneficial effect of the statins on the reduction of fractures,
although not all the results are consistent. The prospective
studies have been undertaken with a small number of patients
and only the bone mineral density has been evaluated. A meta-analysis
of prospective and observational studies has shown a protective
effect on hip fracture (OR: 0.43, 95 % CI 0.25-0.75) and non-vertebral
fracture (OR: 0.69, 95 % CI 0.75-0.88).
The objective of this article is to review the available evidence,
experimental and clinical, of the effect of statins on bone
mass and the reduction of fractures. These drugs may be an
alternative for the treatment of osteoporosis, keeping in
mind that osteoporosis and atherosclerosis affect similar
age groups.
[Back to top]
Biosynthesis, Signal Transduction and Molecular Regulation
of Cytokinins
Yu Ding and Qing-Hu Ma
Cytokinins are master regulators of plant growth and development.
They are involved in the regulation in many important physiological
and metabolism processes. It is always the most important
topic to investigate the cytokinin actions in plant science.
In this review, we briefly introduce the discovery and research
history of cytokinins. Particularly, the recent progress in
cytokinin at the molecular level is discussed, which includes
biosynthetic route, related gene identification, receptors
and signal transduction, and transgenic plants. Based on the
information generated to date, implications and future research
directions are presented.
[Back to top]
Recent Advances in the Analyses of Phytoestrogens
and Their Role in Human Health
M. Humayoun Akhtar and E-S. M. Abdel-Aal
Over the past 20 years, consumption of soy
beans, flax seeds and their products has grown steadily in
western countries. Several epidemiological studies have shown
that a regular diet consisting of products derived from these
grains can reduce the risk of several chronic conditions including
cardiovascular diseases, different forms of cancer, menopausal
symptoms and bone density. It is stipulated that these benefits
are due to bioactive compounds called phytoestrogens, a considerable
number of these compounds have recently generated media exposure;
consequently this has put tremendous pressure on regulatory
agencies to monitor the quality of products. Specifically,
the quantity and nature of active ingredients are determined
in an effort to protect consumers from adulteration and fraud.
This has led to the call for internationally-harmonized, rapid,
sensitive, accurate, and reliable methods for phytoestrogens
analysis in various food matrices, supplements and value-added
specialty products. Also there is a need for methods to accurately
determine phytoestrogens in biological fluids in order to
understand the mode of actions for expected health benefits.
In this review, we compiled recent advances (notably after
2000) on the effect of processing on the stability and nature
of active products, physiological benefits of phytoestrogens,
methods for extraction from a variety of food matrix, separations
using GC and HPLC with detection by UV, DAD, CEAR, and MS.
Current worldwide research on analytical methodologies which
support a harmonized method for the detection of major phytoestrogens
in soy products was discussed.
[Back to top]
Recent Advances in the Analyses of Carotenoids and Their
Role in Human Health
E-S. M. Abdel-Aal and M. Humayoun Akhtar
In addition to the basic nutrients (energy,
protein, vitamins and minerals), plant tissues possess micro
constituents that are essential for human well-being, productive
and healthy lifestyle. They are known as bioactive, physiologically-active,
functional or health-promoting substances and are found in
commonly consumed fruits, vegetables and grains as secondary
metabolites. Majority of these bioactive components (e.g.,
carotenoids, anthocyanins, phenolics) impart their physiological
activities as antioxidants, and some of them such as several
members of carotenoids have more than one mode of action,
i.e., in addition to being antioxidants, they also possess
vitamin A activity. Recent research has supported the role
of carotenoids in maintaining human health and preventing
or reducing the risk of chronic diseases. This has led to
a growing interest in scientific communities to better understand
their molecular and structural properties and their efficacy
as health promoters. Certainly, this requires a collective
effort to develop and validate methodologies and techniques
that are capable to separate, quantify and identify such minor
compounds and their metabolites as well. The present review
was aimed to present the up-to-date analytical techniques
used for the separation and quantification of carotenoids
found in food and plasma. Additionally, their occurrence,
physiological properties, extraction, purification and stability
were discussed.
|
