Application in pharmaceutical analysis

The pharmaceutical analysis deals with an array of therapeutic agents either alone or in combinations that are incorporated in dosage forms of extreme characteristics. The main aim of pharmaceutical analysis is to analyse the compounds accurately and as quickly as possible. Amongst several analytical techniques that are used, HPLC is one of the most commonly used techniques for the analysis and separation of an array of therapeutic agents from their degradation products and impurities. In conventional HPLC, often 

However, while using microemulsion as an eluent, it should be remembered that several factors such as concentration of surfactants, co-surfactants and organic phase, pH of the aqueous phase, column temperature can influence the resolution and retention of the compounds. The microemulsions described so far are based on sodium dodecyl sulphate, short-chain alcohols such as butanol and octanol and aqueous phase of different pH values [78, 159-161]. The utility of w/o microemulsions in the normal phase HPLC analysis has also been described [162]. The microemulsion liquid chromatography (MELC) has been used for resolution of several API such as paracetamol, loratidine, simvastatin, niacinamide, fosinoprilat from their impurities or degradants or metabolic products [159-162]. 

Recently, the application of the microemulsion as an eluent in the high-performance thin layer chromatography (HPTLC) has also been described [ 163]. Microemulsions were used as an eluent for the fingerprinting of licorice extract. As proposed earlier, the microemulsion resulted in much better resolution of the components present in the herbal extract as compared to the conventional eluent. This approach would be very useful in the standardisation of the herbal extracts which often consist of a vast number of components with diverse chemical nature. 

The considerable commercial interest of the pharmaceutical industry in Paracetamol (Sopharma, Bulgaria), polymorphs, and their quantitative analysis, as a result of their wide usage as antipyretic and analgetic agents, has led to the development of suitable methods of characterization. X-ray diffraction (XRD), for example, is a powerful technique for the identification of a crystalline solid phase. IR spectroscopy is also a recommended method. 

Paracetamol (acetaminophen, 4 -hydroxyacetanilide) (Hgure 5.1) is known as three known polymorphs monocUnic (form I), orthoiliambic (form II), and form in [343,344]. The first two are stable enough for experimental structural investigations and for that reason they are fuUy described in the Uteratuie [344-347]. The third form, obtained by melting of the monocUnic modification, is unstable. The phase transition of forms I and II under the effect of hydrostatic pressure and tanperature has been studied [347-350]. The comparative studies of different polymorphs of Paracetamol and clarification of their physical and chonical properties are of great interest and importance because of their bioactivity and appUcabiUty in pharmacology. 

For these reasons we have performed investigations by means of linear-dichroic infrared (IR-LD) spectroscopy analysis of oriented solids on both monoclinic and orthorhombic polymorphs of Paracetamol by the orientation technique as a liquid crystal (LC) suspension. The conventional IR spectral analysis of Paracetamol in solution has been previously danonstraled [351-355]. However, here for the presented CS-NLC orientation technique, IR-LD analysis leads to (a) detailed vibrational assignment of characteristic bands of both polymorphs and (b) the supramo-lecular solid-state structural characterization at room temperature and atmospheric pressure. It also avoids the phase transition and guarantees the study of the different forms. A quantitative approach to the yield determination of monoclinic form I in mixtures with the orthorhombic modification was also illustrated. 

FIGURE 5.1 Chemical diagrams for (1) Paracetamol, (2) Aspirin, (3) Phenacetin (1-acetami-no-4-ethoxybenzol), and salophen ((4-acetamidophenyl) 2-hydroxybenzoate). 

FIGURE 5.2 Chemical diagrams for benzylpenicillin, bacampicillin, and amoxicillin. 

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Although short columns with standard particle sizes have found many practical applications in pharmaceutical analysis, the compromised separation efficiency prohibits their use in situations... 

FIA has also found wide application in pharmaceutical analysis.214,215 Direct UV detection of active ingredients is the most popular pharmaceutical analysis application of FIA. For single component analysis of samples with little matrix interference such as dissolution and content uniformity of conventional dosage forms, many pharmaceutical chemists simply replace a column with suitable tubing between the injector and the detector to run FIA on standard HPLC instrumentation. When direct UV detection offers inadequate selectivity, simple online reaction schemes with more specific reagents including chemical, photochemical, and enzymatic reactions of derivatization are applied for flow injection determination of pharmaceuticals.216... 

Many other selective techniques such as MS, FT-IR, ICP-MS, and electrochemical detection have also been used and several reviews of FIA applications in pharmaceutical analysis appear in the literature.214-216 Several articles are dedicated to pharmaceutical analysis using SIA.217218 FIA and SIA have been applied to high-throughput analysis (up to 200 samples per hour with good... 

This chapter reviews the underlying principles of ion chromatography and its application in pharmaceutical analysis. It provides an overview of eluent systems, applications of gradients, electrolytic eluent generation, suppressors, and stationary phases. Applications of ion chromatography to the confirmation of counter ions, active ingredient analysis, competitive analysis and development work are discussed. 

J. Luypaert, D.L. Massart and Y. Vander Heyden, Near-infrared spectroscopy applications in pharmaceutical analysis, Talanta, 72, 865-883 (2007). 

Atoms are thermally exeited so that they emit light and the radiation emitted is measured. Applications in pharmaceutical analysis... 

A review of capillary electrophoresis applications in pharmaceutical analysis was published in 1993, and the goal of this chapter is to provide an update on the various disciplines within the technique and includes selected applications. Recent developments in the areas of capillary technology, instrumentation, and detection will be reviewed here. Useful strategies for method development involving several classes of pharmaceuticals and biotechnology products will be addressed. The formats within capillary electrophoresis have evolved to such an extent that this chapter is not comprehensive in scope. Therefore, the reader will be directed to other reviews on the various aspects of capillary electrophoresis. Of particular interest to many separation scientists may be a special issue of an Applied Biosystems Newsletter, which addresses the future role of CE, method development in CE, and selected applications in the area of drug analysis and protein separations [7]. 

Steuer et al. compared supercritical fluid chromatography with capillary zone electrophoresis (CZE) and high-performance liquid chromatography (HPLC) for its application in pharmaceutical analysis [24]. Efficiency, performance, sensitivity, optimization, sample preparation, ease of method development, technical capabilities, and orthogonality of the information were the parameters studied. They concluded that SFC is ideal for moderately polar compounds, such as excipients, for which mass detection is required. 

Among some recent reviews of the applications of HPLC are a general one of the application to a wide range of products [261], the application to the resolution of complex biological mixtures [262], its application in pharmaceutical analysis [263], and its use within the clinical laboratory [264]. 

A number of ISEs for organic ions have found application in pharmaceutical analysis. The use of ISEs ranges from determination of excipients and formulary impurities " in finished products to assay of drug product in pharmacokinetic studies. ... 

Accelerated solvent extraction (ASE), also referred to as pressurized liquid extraction,53-55 is a relative newcomer to the battery of extraction techniques. This technique has been applied successfully to problems in environmental analysis56-58 and has recently begun to find a few applications in pharmaceutical analysis as well. Some of these applications have involved biological samples59,60 and solid-dosage forms such as transdermal patches.61... 

In modem pharmaceutical laboratories, CE is still an important technique, but its application in pharmaceutical analysis is less widespread. The rapid developments in LC have to a greater extent overtaken CE techniques, hence the role of CE is either in niche applications such as chiral analysis or as an orthogonal analytical technique to HPLC. 

The provided short review shows good and bad sides of derivative spectrophotometry. It has mainly found application in pharmaceutical analysis for control of pharmaceuticals. It gives good results for samples with well defined composition. A main compound usually is present in its commercial forms at a relatively high level, convenient for sp>ectrophotometric determination. An application of derivative sp>ectrophotometry simplified procedure and allows to determine an active compoimd in presence of matrix (others ingredients, its degradation products) without paimaiy sample pjrepjaration. 

The development of electrochemical applications in pharmaceutical analysis (and to a somewhat lesser degree in food control) was chiefly based on potentiometric titrations, but chiefly on DC polarography and, soemtimes, on coulometric procedures. This phase culminated toward the end of the 1950 s when it became evident that the DC polarographic procedures are not sensitive and selective enough to be applied to all the following problems of pharmaceutical analysis[5] ... 

R. Maleki, A.A. Matin, R. Hosseinzadeh, A. Jouyban, PVC membrane sensor for diclofenac Applications in pharmaceutical analysis and drug binding studies, Pharmazie, 62 (9), 672-677, 2007. 

XQ Guo, YB Zhao, JG Xu. Study on sensitized photochemical fluorescence of menadione sodium bisulfite and its application in pharmaceutics analysis. Anal... 

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