Quantitative analysis of Pentalgin tablets by gradient and isocratic high-performance liquid chromatography

The retention of paracetamol, propyphenazone, caffeine, phenobarbital, and codeine phosphate, which are the components of the new medicine Pentalgin, was studied by reversed-phase high-performance liquid chromatography on a column (150 × 3.9 mm) filled with the Symmetry C18 sorbent (5.0 μm) in the gradient elution mode and on a column (150 × 3.9 mm) filled with the Nova-Pak CN HP sorbent (4.0 μm) as a function of the profile and composition of the gradient and as a function of the concentrations of acetonitrile and KH₂PO₄ and the pH of the mobile phase, respectively, with detection at 212 nm. The optimum composition of the mobile phase was selected. The time of separation was 16 and 11 min for the gradient and isocratic elution modes, respectively. The procedures were used for the analysis of a preproduction sample of the tablets. The procedures provide accurate and reproducible results of analysis; however, the isocratic version is preferable for mass production control as a technically simpler technique.     

Quantitative analysis of Pentalgin N tablets by gradient and isocratic high-performance liquid chromatography

Two procedures were proposed for the quantitative analysis of the drug Pentalgin N with the use of HPLC in gradient and isocratic modes. Analgin (dipyrone), caffeine, naproxen, phenobarbital, codeine, an analgin degradation product, and sodium sulfite (added to the test solution to stabilize analgin) were separated on a column (150 × 3.9 mm) packed with Nova-Pak C18 (4.0 μm) with elution with a 0.00625 M KH₂ PO₄ solution with an acetonitrile concentration gradient from 10 to 60 vol % in 10 min or on a column (150 × 3.9 mm) packed with Nova-Pak CN HP (4.0 μm) with elution with a 0.0110 M KH₂ PO₄ solution (pH 5.8) containing 5 vol % acetonitrile. The wavelength of the diode-array detector was 212 nm. Model solutions containing all of the active principles and additives of the tablets were analyzed, and the performance characteristics of both procedures were calculated. Both procedures afford reliable analytical results; however, the isocratic version is technically simpler and more preferable for product control in commercial production.     

Quantitative determination by high-performance liquid chromatography of acetylsalicylic acid and related substances in tablets

High-performance liquid chromatography on a Zorbax C8 7-micron column (25 cm X 0.46 cm I.D.) with methanol-water-1 M phosphoric acid (59:36:5) as the mobile phase has been used for the analysis of several naturally aged batches of fourteen brands of acetylsalicyclic acid tablets. The extraction solvent is methanol, containing 2% v/v of formic acid. Salicylic acid is the main impurity. Acetylsalicylsalicylic acid is the second most important impurity, and the corresponding salicylsalicylic acid is rarely present. Buffered or dispersible tablets contain relatively more of the latter two impurities and eventually also the corresponding higher oligomers. Acetylsalicylic anhydride is always a minor impurity. Comparison is made with classical spectrophotometric methods, which are observed to be selective for salicylic acid.     

Quantitative determination of celanide by high-performance liquid chromatography

Methods have been developed for the quantitative determination of celanide [lanatoside C] in substances, in solutions for injection, and in tablets by high-performance liquid chromatography, with the aid of which it is possible to determine small amounts of celanide (0.025 mg/ml) with adequate accuracy. The relative error of the determination does not exceed ±4.0%.All-Union Scientific-Research Institute of Physical Culture, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 476–479, July–August, 1983.     

Quantitative analysis of Codelac Broncho tablets and syrup by high-pressure liquid chromatography

A procedure was proposed for quantitative analysis of Codelac Broncho tablets and syrup, a new original drug, by high-pressure liquid chromatography. The active principles of the tablets were separated in 6 min with an efficient resolution of all component peaks. Preproduction tablet samples were analyzed. The results of the analysis meet the requirements of normative technical documentation and technologic loads. The adequacy of the results was validated by the analysis of model solutions that contained all active principles and adjuvants. For the syrup, two versions of analysis were proposed, in isocratic and gradient elution modes. These versions are virtually equivalent with respect to the analysis time and precision. The isocratic elution version is, however, easier to implement and is proposed for inclusion into the draft pharmacopoeic standards for commercial production.     

Determination of benzhexol hydrochloride in tablets by high-performance liquid chromatography

Separation on a LiChrosorb C₂ reversed-phase column with methanolic ammonium dihydrogenphosphate as eluent provides a simple determination of benzhexol hydrochloride in tablets containing 2–5 mg of the drug. Common excipients do not interfere.     

Quantitative analysis of three chiral pesticide enantiomers by high-performance column liquid chromatography

Methods for the enantiomeric quantitative determination of 3 chiral pesticides, paclobutrazol, myclobutanil, and uniconazole, and their residues in soil and water are reported. An effective chiral high-performance liquid chromatographic (HPLC)-UV method using an amylose-tris(3,5-dimethylphenylcarbamate; AD) column was developed for resolving the enantiomers and quantitative determination. The enantiomers were identified by a circular dichroism detector. Validation involved complete resolution of each of the 2 enantiomers, plus determination of linearity, precision, and limit of detection (LOD). The pesticide enantiomers were isolated by solvent extraction from soil and C18 solid-phase extraction from water. The 2 enantiomers of the 3 pesticides could be completely separated on the AD column using n-hexane isopropanol mobile phase. The linearity and precision results indicated that the method was reliable for the quantitative analysis of the enantiomers. LODs were 0.025, 0.05, and 0.05 mg/kg for each enantiomer of paclobutrazol, myclobutanil, and uniconazole, respectively. Recovery and precision data showed that the pretreatment procedures were satisfactory for enantiomer extraction and cleanup. This method can be used for optical purity determination of technical material and analysis of environmental residues.     

Quantitative analysis of hyaluronic acid by high-performance liquid chromatography of streptomyces hyaluronidase digests

The separation and quantitative analysis of streptomyces hyaluronidase ( HAase ) degradation products of hyaluronic acid (HA) by high-performance liquid chromatography are described. The substituted 4,5-unsaturated tetrasaccharide and hexasaccharide which result from the digestion of HA are quickly separated on a silica gel (Zorbax SIL) column. The assay of HA is linear between 5 and 250 micrograms of HA. This procedure is suitable for some weakly acidic glycosaminoglycan contaminants having similar properties to those of HA.     

Quantitative analysis of the Maksikold multicomponent anticatarrhal preparation by pH-gradient high-performance liquid chromatography

A procedure was developed for the rapid analysis of a new multicomponent anticatarrhal medication Maksikold by high-performance liquid chromatography (HPLC). The possibility of the simultaneous determination of all active substances in the preparation, including ascorbic acid, is an advantage of the proposed procedure. For the efficient resolution of the peaks of analytes and interfering additives, a mobile phase with the pH varied in the course of an experimental run was used. The procedure was used to analyze pilot samples of the preparation. The results obtained exhibit a high precision.     

Simultaneous assay of olanzapine and fluoxetine in tablets by column high-performance liquid chromatography and high-performance thin-layer chromatography

This paper describes validated high-performance liquid chromatographic (LC) and high-performance thin-layer chromatographic (TLC) methods for the simultaneous estimation of olanzapine and fluoxetine in pure powder and tablet formulations. The LC separation was achieved on a Lichrospher 100 RP-180, C18 column (250 mm, 4.0 mm id, 5 microm) using 0.05 M potassium dihydrogen phosphate buffer (pH 5.6 adjusted with o-phosphoric acid)-acetonitrile (50 + 50, v/v) as the mobile phase at a flow rate of 1 mL/min and ambient temperature. The TLC separation was achieved on aluminum sheets coated with silica gel 60F254 using methanol-toluene (40 + 20, v/v) as the mobile phase. Quantitation was achieved by measuring ultraviolet absorption at 233 nm over the concentration range of 10-70 and 40-280 microg/mL with mean recovery of 99.54 +/- 0.89 and 99.73 +/- 0.58% for olanzapine and fluoxetine, respectively, by the LC method. Quantitation was achieved by measuring ultraviolet absorption at 233 nm over the concentration range of 100-800 and 400-3200 ng/spot with mean recovery of 101.53 +/- 0.06 and 101.45 +/- 0.35% for olanzapine and fluoxetine, respectively, by the TLC method with densitometry. These methods are simple, precise, and sensitive, and they are applicable for simultaneous determination of olanzapine and fluoxetine in tablet formulations.     

Faster analysis by reversed-phase high-performance liquid chromatography

Summary Many analysts are not taking full advantage of the high speed possibilities of modern LC. Some analytical procedures reported in the literature, and many in regular use in control laboratories, could be achieved in less time without loss in precision. Some factors which affect retention times are discussed and the advantages and disadvantages of employing shorter column lengths and finer packing materials in reversed-phase HPLC are examined. The effect on efficiency of increased flow rates with 10,5 and 3 m ODS materials is shown. The ability to couple shorter column lengths without loss of efficiency is also demonstrated. This allows a minimum length to be selected that gives adequate resolution. Examples of high speed separations are shown and limitations in state of the art HPLC equipment and chromatographic data systems are discussed briefly.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Quantitative analysis of hydrophobic pulmonary surfactant proteins by high-performance liquid chromatography with light-scattering detection

A new method for the separation and quantification of two hydrophobic lung surfactant proteins (SPs) is described. It is based on size-exclusion chromatography using the apolar stationary phase butyl silicagel with a pore size of 30 nm and isocratic elution with chloroform, methanol and trifluoroacetic acid. The samples were prepared from sheep lung lavage fluid by centrifugation and fractional extraction with butanol and chloroform–methanol. The chromatograms show three peaks in the elution order SP-B, SP-C and lipids. A small peak ahead of SP-B, which disappeared after reduction with 2-mercaptoethanol, was oligomeric SP-B. The response of the evaporative light-scattering detector was non-linear. For preparative high-performance liquid chromatography ultraviolet detection at 279 nm is recommended.     

Quantitative trace analysis of surfactant mixtures by reversed-phase high-performance liquid chromatography with refractometric detection

Reversed-phase partition liquid chromatography on an octyl column allowed the separation of complex non-ionic poly(ethylene oxide)-type (PEO) surfactant mixtures resulting from the condensation of ethylene oxide with saturated fatty alcohols. As these compounds have no chromophoric group, they were detected by differential refractometry. Accurate quantitation of each oligomer (C_mE_n) allowed the main characteristics of each non-ionic surfactant, i.e., the nature and percentage of the different alkyl chains (with m = number of carbons) and the average number of ethylene oxide units ( ) to be obtained in one analysis. Preparative liquid chromatography was used to isolate pure oligomers with a higher degree of ethoxylation (n =10, 11, 12, 14 and more) than the commercially available standards, in order to determine a wide range of refractometric response factors. It appeared that they are constant as a function of alkyl chain length (C₁₀-C₁₆ range) but that they vary significantly and non-linearly as a function of the degree of ethoxylation, n. It was found that neglecting the variation of response factors can result in a distortion of the average ethoxylation number and in an unsatisfactory quantitative analysis. This chromatographic method, involving a quantitative and reproducible trace enrichment procedure with liquid-solid extraction, allowed the analysis of very dilute PEO mixtures in water. The components of complex PEO mixtures in water were determined at concentrations as low as 0.5 mg 1⁻¹, without any distortion of the distribution, the detection limit being 0.25 μg 1⁻¹ for the less abundant oligomers.     

Determination of tianeptine in tablets by high-performance liquid chromatography with fluorescence detection

A sensitive and selective high-performance liquid chromatographic method has been developed for the determination of tianeptine (Tia) in tablets. The method is based on derivatization of Tia with 4-chloro-7-nitrobenzofurazan (NBD-CI). A mobile phase consisting of acetonitrile-10 mM orthophosphoric acid (pH 2.5; 77 + 23) was used at a flow rate of 1 mL/min on a C18 column. The Tia-NBD derivative was monitored using a fluorescence detector, with emission set at 520 nm and excitation at 458 nm. Gabapentin was selected as an internal standard. Linear calibration graphs were obtained in the concentration range of 45-300 ng/mL. The lower limit of detection (LOD) was 10 ng/mL at a signal-to-noise ratio of 4. The lower limit of quantitation (LOQ) was 45 ng/mL. The relative standard values for intra- and interday precision were <0.46 and <0.57%, respectively. The recovery of the drug samples ranged between 98.89 and 99.85%. No chromatographic interference from the tablet excipients was found. The proposed method was validated in terms of precision, robustness, recovery, LOD, and LOQ. All the validation parameters were within the acceptance range. The proposed method was applied for the determination of Tia in commercially available tablets. The results were compared with those obtained by an ultraviolet spectrophotometric method using t- and F-tests.     

Rapid analysis of phentolamine by high-performance liquid chromatography

A rapid liquid chromatographic method is validated for the quantitative analysis of phentolamine. Phentolamine exists in three forms for this investigation: as a mesylate salt, hydrochloride salt, and free base. In solution, phentolamine dissociates from its salt and is chromatographed as free phentolamine. This validation confirms the analysis of each form, which is simply based upon molar mass differences encountered in weighing. As such, both the United States Pharmacopeia hydrochloride and mesylate standards are used throughout this validation to demonstrate this equivalency. The validation demonstrates that this method may be used to quantitate phentolamine, regardless of its salt form.