High Performance Liquid Chromatographic Assay of Hydromorphone Hydrochloride Injection

Abstract

A stability indicating high performance liquid chromatographic (HPLC) method for determining hydromorphone hydrochloride in dosage forms is described. The drug was chromatographed on a C₁₈ reverse phase column, using a mobile phase consisting of sodium lauryl sulfate, acetic acid, acetonitrile and water, and detected at 280 nm. Linearity of detector response to the concentration was confirmed. The procedure showed excellent reproducibility and gave quantitative recoveries of the drug from spiked placebos. Photodegraded samples of the dosage form, were assayed by the HPLC procedure and the current USP spectrophotometric procedure. Comparison of the results showed that the USP procedure is only partially stability indicating.     

Adsorption of the anionic surfactant sodium dodecyl sulfate on a C18 column under micellar and high submicellar conditions in reversed‐phase liquid chromatography

Micellar liquid chromatography makes use of aqueous solutions or aqueous‐organic solutions containing a surfactant, at a concentration above its critical micelle concentration. In the mobile phase, the surfactant monomers aggregate to form micelles, whereas on the surface of the nonpolar alkyl‐bonded stationary phases they are significantly adsorbed. If the mobile phase contains a high concentration of organic solvent, micelles break down, and the amount of surfactant adsorbed on the stationary phase is reduced, giving rise to another chromatographic mode named high submicellar liquid chromatography. The presence of a thinner coating of surfactant enhances the selectivity and peak shape, especially for basic compounds. However, the risk of full desorption of surfactant is the main limitation in the high submicellar mode. This study examines the adsorption of the anionic surfactant sodium dodecyl sulfate under micellar and high submicellar conditions on a C₁₈ column, applying two methods. One of them uses a refractive index detector to obtain direct measurements of the adsorbed amount of sodium dodecyl sulfate, whereas the second method is based on the retention and peak shape for a set of cationic basic compounds that indirectly reveal the presence of adsorbed monomers of surfactant on the stationary phase.     

Reversed‐Phase High‐Performance Liquid Chromatographic Separation and Determination of 4‐Amino‐azobenzene‐4′,5‐disulfonic Acid and Related Products in Industrial Wastewater Effluents

A simple and rapid reversed‐phase high‐performance liquid chromatographic method for the separation and determination of 4‐amino‐azobenzene‐4′,5‐disulfonic acid (AABDS) and its process‐related impurities was developed. The separation was achieved on a μ‐Bondapak C₁₈ column using 0.15 M ammonium sulfate‐acetonitrile (55:45) (v/v) as eluent. A UV‐visible spectrophotometric detector fixed at 386 nm was used both for detection and quantitation. The method was used not only for quality assurance but also for process development and wastewater management of AABDS.     

Development and Validation of a Micellar Liquid Chromatographic Method with UV Detection for Determination of Azithromycin in Tablets and Capsules

A rapid and simple micellar liquid chromatographic method that does not require use of specific chromatographic columns has been developed and validated for azithromycin determination. The method uses a Hypersil C₁₈ column at 60 °C, 1-butanol–pH 6.86 phosphate buffer solution–water, 15:25:60 (v/v), containing 0.10 M sodium dodecyl sulfate, as mobile phase, and UV-detection at 215 nm. Different characteristics of the method were validated satisfactorily. The specificity, accuracy, linearity, precision (repeatability), and robustness of the method were demonstrated. The method proved suitable for determination of the azithromycin content of capsules and uncoated tablets.Revised: 5 February and 11 March 2004     

A simple isocratic LC method for quantification of trace-level inorganic degradation impurities (ferricyanide,ferrocyanide, nitrite,and nitrate) in sodium nitroprusside injection and robustness by quality using design approach

This study developed and validated a trace-level quantification inorganic impurities method using reversed-phase HPLC and performed the robustness check using quality-by-design approach by varying the multiple factors simultaneously. This method is economical and simple and exhibits its stability-indicating nature [for the determination of ferrocyanide ([Fe(CN)₆]^4–), ferricyanide ([Fe(CN)₆]³⁻), nitrate (NO₃^–), and nitrite (NO₂^–)] in sodium nitroprusside (SNP) drug substance and liquid dosage form. Chromatographic separation was achieved using a USP L43 column (ACE PFP, 150 × 4.6 mm, 3 μm) with a simple isocratic elution. The buffer consists of potassium dihydrogen phosphate (50 mM), tetrabutylammonium hydrogen sulfate (9 mM), and tetrabutylammonium hydroxide (25 mM). The buffer pH was adjusted to 7.2 with tetrabutylammonium hydroxide. The mobile phase was mixed with the buffer and acetonitrile (68:32 v/v). The flow rate was 0.8 mL/min, column temperature was maintained at 30°C, and injection volume was 5.0 μL. The SNP impurities were monitored at 225 nm using a UV detector. Further, the method was validated per the International Council for Harmonisation (ICH) guidelines, and forced degradation studies were carried out under different stress conditions. The detector responses were plotted against concentrations, and correlation was linear (r > 0.999) over the range of 0.8–7.5 μg/mL for ferricyanide; 1.0–37.5 μg/mL for SNP; and 0.2–7.5 μg/mL for ferrocyanide, nitrite, and nitrate. The method repeatability was established for all the impurities with relative standard deviation (%), and the results were found to be less than 2.0.     

Green micellar HPLC analysis of three angiotensin‐converting enzyme inhibitors in their mixtures with hydrochlorothiazide and modeling of their retention behavior by fitting to Foley's model

We present an environmentally friendly method for the analysis of three angiotensin‐converting enzyme inhibitors and hydrochlorothiazide simultaneously using a green micellar eluent for the first time. The chromatographic separation of enalapril maleate, lisinopril dihydrate, benazepril hydrochloride, and hydrochlorothiazide was implemented on an octadecyl silica column with a solution containing sodium dodecyl sulfate (0.12 M), 1‐propyl alcohol (10% v/v), triethylamine (0.3% v/v), and H₃PO₄ (0.02 M) at pH 3.6 as the mobile phase and UV detection at 210 nm. Validity of the method was confirmed and it exhibited good linearity within the ranges of 5.0–50.0 μg/mL for hydrochlorothiazide and 10.0–60.0 μg/mL for the three angiotensin‐converting enzyme inhibitors with a limit of detection of 0.39 to 1.15 μg/mL for all the studied drugs. The developed micellar high‐performance liquid chromatography method enables the quantification of the targeted angiotensin‐converting enzyme inhibitors in combined tablets with hydrochlorothiazide by isocratic elution. There is no need for special precautions to prevent broadening and splitting of their chromatographic peaks. The method fulfills the society rights for safe and green analytical methods. The retention behavior of the four studied drugs was fitted to Foley's model and their association equilibria to the micelles (K _AM) and to the surface‐modified stationary phase (K _AS) were calculated.     

Simultaneous determination of five bioactive constituents in the traditional Chinese medicinal preparation refined xue-fu-zhu-yu-tang by high-performance liquid chromatography with diode-array UV detection

A high-performance liquid chromatographic method for the simultaneous determination of oxypaeoniflorin, paeoniflorin, ferric acid, naringin, and neohesperidin in a traditional Chinese medicinal preparation, refined xue-fu-zhu-yu-tang, was developed. Separations were carried out with a ZORBAX SB-C₁₈ column along with an Agilent C₁₈ precolumn by linear gradient elution using 1% acetic acid-methanol (v/v: 0 min, 80/20; 15 min, 70/30; 35 min, 60/40; 55 min, 60/40) as the mobile phase at a flow rate of 0.5 mL/min. The analytes were detected with a diode-array detector at their maximum UV wavelengths. The correlation coefficients of the calibration curve for the analytes exceeded 0.9999. The recoveries were in the range 95.95–104.42 % with RSD less than 1.85%, and the precision of this method was better than 1.80%. The effects of several factors on the chromatographic behavior and sample extraction of the analytes were compared. In addition, the contents of these bioactive constituents in six different samples of this preparation were analyzed by using the optimized high-performance liquid chromatographic method. The text was submitted by the authors in English.     

Microbore Liquid Chromatography For Analysis of Plasma Pindolol Concentrations

Abstract

Isocratic high-performance liquid chromatographic assay of pindolol with use of a microbore column was developed. the sample preparation involves extraction of alkalized plasma into ether and back extraction into 0.05 N H₂SO₄. Metoprolol was used as the internal standard. Chromatographic separation is performed on a microbore C18 (5 μm) column using acetonitrile-disodium hydrogenphosphate buffer (37:63) containing 20 mM sodium dodecyl sulfate as the mobile phase. the detection is achieved by using a fluorescence detector operated at the excitation and emission wavelengths of 260 and 310 nm, respectively. Acceptable reproducibility and accuracy data are presented over the concentration range normally encountered in human plasma samples. the lower detection limit is 2.5 ng/ml. This sensitivity has been found to be adequate for routine analysis of pindolol in human plasma samples, making the method applicable to pharmacokinetic studies and clinical trials.     

Application of a rapid and selective method for the simultaneous determination of carebastine and pseudoephedrine in human plasma by liquid chromatography–electrospray mass spectrometry for bioequivalence study in Korean subjects

We describe a simple, rapid and sensitive high‐performance liquid chromatography–electrospray ionization tandem mass spectrometric method that was developed for the simultaneous determination of carebastine and pseudoephedrine in human plasma using cisapride as an internal standard. Acquisition was performed in multiple‐reaction monitoring mode by monitoring the transitions: m/z 500.43 > 167.09 for carebastine and m/z 166.04 > 147.88 for pseudoephedrine. The devised method involves a simple single‐step liquid–liquid extraction with ethyl acetate. Chromatographic separation was performed on a C₁₈ reversed‐phase chromatographic column at 0.2 mL/min by isocratic elution with 10 mM ammonium formate buffer–acetonitrile (30:70, v/v; adjusted to pH 3.3 with formic acid). The devised method was validated over 0.5–100 ng/mL of carebastine and 5–1000 ng/mL of pseudoephedrine with acceptable accuracy and precision, and was successfully applied to a bioequivalence study involving a single oral dose (10 mg of ebastine plus 120 mg of pseudoephedrine complex) to healthy Korean volunteers. Copyright © 2010 John Wiley & Sons, Ltd.     

Density,speed of sound,refractive index and derivatives properties of the binary mixture n-hexane + n-heptane (or n-octane or n-nonane), T = 288.15 – 313.15 K

This article reports experimental values of refractive index n_D , density ρ, speed of sound u, isentropic compressibility κ_s, excess molar volume of mixing V _E, deviations of refractive index δn_D and isentropic compressibility δκ_s of the binary mixture n-hexane + n-alkane from T = (288.15 to 323.15) K and atmospheric condition. The corresponding excess derived property was computed from the experimental data. Parameters of analytical expressions which represent the composition dependences of the derived property are reported. Values of physical properties were compared with the results obtained by different prediction methods.     

Comparative Study of Packed and Capillary Column Chromatography for the Characterization of Vacuum Gas Oils

Gas chromatographic methods are of widespread use in the petroleum industry for assessing petroleum and derivatives quality. The feedstocks for catcracking processes are very sensitive to the n-paraffin contents, which can be accurately determined using capillary column chromatography. Nevertheless, packed column chromatography does have potential advantages, viz. sometimes shorter analysis times, lower costs, higher column capacity, for vacuum gas oil analysis. This paper presents a method for such a determination using a Dexsil-300 packed column. The results obtained (n-alkane contents, carbon number distribution) agree fairly well with those obtained on a 30 m × 0.25 mm DB-1 fused silica capillary column.     

Study on Binding Properties of Poorly Soluble Drug Trimethoprim in Anionic Micellar Solutions

Binding and distribution properties of trimethoprim (TMP) in the presence of various anionic surfactants; sodium octyl sulfate (C₈SO₄Na), sodium decyl sulfate (C₁₀SO₄Na), sodium lauryl sulfate (C₁₂SO₄Na), and sodium tetradecyl sulfate (C₁₄SO₄Na) has been studied by conductivity, spectrophotometry and surface tension measurements. The surface properties of anionic surfactants, that is, maximum surface excess concentration (Γ _max ) and minimum area per surfactant molecule (A _min ) at the air/water interface have been evaluated in the absence and presence of TMP using Gibbs adsorption isotherm. From conductivity data the ionization degree and counterion binding parameter have been obtained. Spectrophotometric experiments were used to determine binding constants of TMP to anionic micelles. With the increasing alkyl chain of surfactants, the interaction becomes stronger, which shows the importance of hydrophobic forces and incorporation of TMP molecules to the pure micelles of anionic surfactants increased. The results obtained from the surface tension and conductometric studies have been correlated with those obtained from the spectroscopic studies and binding tendency of TMP to anionic micelles followed the order as: C₁₄SO₄Na > C₁₂SO₄Na > C₁₀SO₄Na > C₈SO₄Na. From these results, the study of the interaction TMP in different anionic micellar solutions provided information about the characteristics of binding properties of poorly soluble drugs.     

Capillary gas chromatography of lower aliphatic C2?C5 aldehydes in the free form as a group of pungent odorants in air

The capillary gas chromatography of the C₂-C₅ lower aliphatic aldehydes (e.g.,acetaldehyde, propionaldehyde, n- and i-butyraldehydes, n- and i-valeraldehydes) which, in the free form in air, have unpleasant odors and low threshold odor values, has been studied using cold-trap preconcentration with liquid oxygen. The capillary column outlet was connected to enable simultaneous detection by FID, ECD, FPD AND FTD (SID).     

High-performance liquid chromatographic determination of glycogen in sea urchin gonads with refractive index detection

A high-performance liquid chromatographic method using refractive index detection for the determination of glycogen in sea urchin (Paracentrotus lividus) gonads is developed. After alkaline digestion with sodium carbonate, samples are adjusted to pH 4.6 with citric acid and incubated with amyloglucosidase to hydrolyze the glycogen. The resulting glucose is determined using a Spherisorb NH2 column as the stationary phase and an acetonitrile-water mixture (80:20, v/v) as the mobile phase. The relative standard deviation (%) was 3.57, the limit of detection was 40.1 microg/mL, and the recovery percentage was 97.2%.     

Implications of on-line FTIR detection in the separation of coal-derived products via HPLC with polar modifiers

Summary Fourier-transform infrared spectrometry (FTIR) was utilized as a detection system for high-performance liquid chromatography of polar compounds on a normal bonded-phase system. In addition to FTIR, UV (254 nm) and refractive index detection were employed in the separation of model compounds containing oxygen and nitrogen atoms in their molecules (phenols, alcohols, neutral and weakly basic nitrogen compounds). A polar amino-cyano (PAC) bonded-phase column was employed with a binary mobile phase (98:2 CDCl₃:CH₃CN). The separations and the information gained from each detector is discussed, including interactions between sample material and mobile phase. A polar fraction of a coal-derived product is also chromatographed under identical conditions. The results based on FTIR detection and chromatographic retention behavior suggest the exclusive presence of hindered and unhindered phenols.     

Liquid chromatography techniques for characterizing poly(Vinyl Alcohol)

Poly(vinyl alcohol) (PVOH) samples may contain several heterogeneities requiring the development of chromatographic techniques for characterization. Size exclusion separations have been carried out using a number of aqueous eluents, incorporating electrolyte, or electrolyte/organic modifier, or surfactant. The most favourable molecular size separation was obtained using 0.25% w/v sodium lauryl sulfate as eluent. Reasonable values for molecular weights of PVOH samples have been determined. Compositional distributions in copolymer systems can be assessed using high-performance liquid chromatography employing a reversed-phase separation mechanism. For poly(vinyl alcohol), gradient elution with water/tetrahydrofuran (THF) with a wide pore polystyrene-based packing produced separations dependent on degree of hydrolysis and sequence length distribution. The elution results were verified with a column packed with non-porous beads. Partially hydrolysed PVOH samples appeared to have a broad distribution of composition.     

A sensitive LC‐MS/MS method for the quantification of febuxostat in human plasma and its pharmacokinetic application

An improved, simple and highly sensitive LC‐MS/MS method has been developed and validated for quantification of febuxostat with 100 μL human plasma using febuxostat‐d₇ as an internal standard (IS) according to regulatory guidelines. The analyte and IS were extracted from human plasma via liquid–liquid extraction using diethyl ether. The chromatographic separation was achieved on a Zorbax C₁₈ column using a mixture of acetonitrile and 5 mm ammonium formate (60:40, v/v) as the mobile phase at a flow rate of 0.5 mL/min. The total run time was 5.0 min and the elution of febuxostat and IS occurred at 1.0 and 1.5 min, respectively. A linear response function was established for the range of concentrations 1–6000 ng/mL (r > 0.99). The precursor to product ion transitions monitored for febuxostat and IS were m/z 317.1 → 261.1 and 324.2 → 262.1, respectively. The intra‐ and inter‐day precisions (%RSD) were within 1.29–9.19 and 2.85–7.69%, respectively. The proposed method was successfully applied to pharmacokinetic studies in humans. Copyright © 2013 John Wiley & Sons, Ltd.     

Development and validation of a reversed-phase HPLC method with post-column iodine-azide reaction for the determination of thioguanine

A high-performance liquid chromatographic method of reversed-phase with a post-column iodineazide reaction has been developed and validated for the determination of thioguanine. Isocratic elution was performed on a column of C₁₈ using acetonitrile- water-sodium azide solution (1.5%; pH 6.5) 16: 34: 50 (v/v/v) as a mobile phase with flow-rate of 0.5 mL/min. Monitoring of unreacted iodine in post-column iodine-azide reaction induced by thioguanine resulted in its detection at 350 nm. The method applied to thioguanine was linear within the scope of values 8–100 nM (r ² > 0.9988). The relative standard deviation (RSD < 4.2%) and the recovery (>96%) prove that the intra-day precision and the accuracy were satisfactory. The lower limits of detection (LLD) and quantification (LLQ) of thioguanine were established at the levels of 6 and 8 nM, respectively. The elaborated method was validated and applied to thioguanine determination in tablets.     

Simultaneous Carbohydrate Chromatography and Unsuppressed Ion Chromatography in Detecting Fruit Juices Adulteration

This paper is the first one investigating the simultaneous use of carbohydrate chromatography and ion chromatography to obtain in one run conclusive data on juice’s authenticity. A hybrid liquid chromatographic system with conductivity and differential refractive index detection, equipped with an Universal Cation 7u column for cation analysis and with a EC 250/4 Nucleodur 100-5 NH₂ RP column for carbohydrate analysis, was designed for this study. In less than 18 min, this configuration can separate simultaneously six cations (lithium, sodium, ammonium, potassium, magnesium and calcium) and four carbohydrates (fructose, glucose, saccharose and maltose). Commercial orange and apple juices obtained from the Romanian market were analyzed during this research.