Current Pharmaceutical Analysis - Volume 6, Issue 1, 2010

The management of well-differentiated thyroid cancer requires endogenous or exogenous thyrotropin (TSH) stimulation for diagnostic and therapeutic purposes. The rationale is to increase the sensitivity of follow-up tests and to optimize the radioiodine uptake, respectively. Withdrawal of L-thyroxine therapy in order to provoke endogenous stimulation and elevation of TSH is associated with symptomatic hypothyroidism that significantly affects quality of life. More importantly, because TSH stimulates growth of thyroid cells, prolonged TSH elevation may worsen the thyroid cancer, and the profound hypothyroidism may aggravate other underlying systemic diseases. As an alternative to thyroxine withdrawal, exogenous stimulation consists of two intramuscular injections of recombinant human thyrotropin α (rhTSH). This procedure is effective in terms of sufficient TSH stimulation and obviates development in the patient of the signs and symptoms of hypothyroidism. Taking into consideration the increased incidence of thyroid cancer, as well as the necessity for life-long follow-up, the optimal management of the disease must meet goals for efficacy, safety, quality of life and optimal cost/benefit ratio. This article reviews current standard procedures and potential novel clinical applications of rhTSH for the management of well-differentiated thyroid cancer.

The majority of the drugs currently employed in the treatment and prophylaxis of malaria are chiral and show enantioselective pharmacodynamic and pharmacokinetic properties in humans and animals. Thus, the assessment of the disposition of these enantiomers in the body using reliable and feasible methods is required to improve the therapy of this disease. Several methods devoted to the enantioselective analysis of the antimalarial drugs and their respective metabolites have been described. Therefore, this article intends to review the methods reported for the enantioselective determination of these analytes with a focus on biological matrices and particular attention will be given to the modern techniques of analysis and sample preparation.

The development and applications of molecular imprinting-based chemiluminescence detection method are reviewed with special attention to pharmaceutical analysis. This review is organized according to the fundamental types of chemiluminescence reactions involved. The marriage of this technique with immunoassay is also discussed.

The discrimination and evaluation of stereoselective metabolism of enantiomers are of paramount significance for developing effective and safe chiral drugs. However, there is still a lack of comprehensive and in-depth understanding of stereospecific disposition of chiral components in Herbal Medicines. In this article, stereoselective methods including capillary electrophoresis, high-performance liquid chromatography, gas chromatography, supercritical fluid chromatography and hyphenation techniques for chiral drug metabolism studies are reviewed. Furthermore, applications of modern analytical techniques to study enantioselective metabolic profiling of the active components from Herbal Medicines in vitro and in vivo in recent years are also presented and the representative examples are enumerated.

Multicommutation is a methodology of increasing use for the development of chemical analysis systems. Specifically, it refers to continuous-flow configurations designed with computer-controlled commutators. The flow system, based on the implementation of solenoid valves in Flow Injection Analysis (FIA), is called Multicommutated Flow System (MCFIA). These flow systems can be easily re-configured by just changing the procedure with the software, resulting in increased versatility, potential for automation and minimization of both reagent consumption and waste generation. The use of solenoid pumps for propelling the solutions has been recently introduced and is known as Multipumping Flow Systems (MPFS). Finally, Multisyringe Flow Injection Analysis (MSFIA) has been developed implementing multicommutation principles in a modified Sequential Injection Analysis (SIA) system. This review covers a brief description about the fundamentals of the above mentioned methodologies as well as their application to pharmaceutical and clinical analysis. Several examples are given and some particular aspects are highlighted, such as the differences between measuring the analytical signal in solution or on a solid support (flow-through optosensor), a detailed classification of the reported methods in terms of the flow technique employed, or the novelty of each published method.