Development and Validation of a Reversed-Phase High-performance Liquid Chromatography Method for Determination of Desmopressin in Chitosan Nanoparticles

A simple isocratic reversed-phase high performance liquid chromatographic method was developed for determination of released desmopressin from chitosan nanoparticles in the in vitro media. The chromatographic separation was achieved with acetonitrile/water (25:75, v/v), in which water contained 0.1% v/v trifluoroacetic acid with pH=2.5 as mobile phase, a Chromolith^® Performance RP-18e column (150×4.6 mm; 5 μm) kept at 40° and ultraviolet detection at 220 nm. The compound was eluted isocritically at a constant flow rate of 1.6 ml/min. The method was validated according to the International Conference on Harmonisation guidelines. The validation characteristics included accuracy, precision, linearity rang, selectivity, limit of detection, limit of quantitation and robustness. The calibration curve was linear (r>0.9999) over the concentration rang 0.5-100 μg/ml. The limit of detection and limit of quantitation in the release media were 0.05 and 0.5 μg/ml, respectively. The proposed method had an accuracy of and intra- and inter-day precision <4.2. Furthermore, to evaluate the performance of the proposed method, it was used in the analysis of desmopressin level in real samples containing chitosan nanoparticles in the in vitro media.     

A Sensitive Method for Quantitation of Rifabutin and Its Desacetyl Metabolite in Human Biological Fluids by High-Performance Liquid Chromatography (HPLC)

Sensitive HPLC-UV methodology has been developed and validated for quantitating rifabutin, an antimycobacterial, and its 25-desacetyl metabolite, LM-565, in human plasma and urine. The HPLC separation for both plasma and urine samples was performed on an ODS, 5-µm, reverse-phase column (25 cm × 4.6-cm ID) using a mobile phase of acetonitrile/0.05 M potassium phosphate, pH 4.2, with triethylamine, (38:61.5:0.5, v/v), at a flow rate of 1.0 ml/min. The separation eluate was monitored by absorbance at 275 nm. Plasma samples (1 ml) were spiked with an internal standard (medazepam), buffered at pH 7.4 and extracted with 80:20 (v/v) hexane:ethyl acetate, and then back extracted with acidified water (0.05 M H3PO4). Linearity was established between 5.0–800 and 2.5–400 ng/ml for rifabutin and LM-565, respectively. Intraday imprecision for rifabutin and LM-565 plasma quality controls prepared at 7.3 and 3.2 ng/ml, respectively, was <15% relative standard deviation (RSD). Absolute recovery for parent drug and metabolite, from plasma, was >90% throughout the respective dynamic ranges and >70% for medazepam. Urine samples (1 ml) were acidified with 50 µl of 3.6 M H2SO4 and diluted with 0.1 M ammonium acetate. Linearity was established between 100 and 5000 ng/ml for both rifabutin and LM-565. Intraday imprecision for a urine control at 200 ng/ml was 12% RSD for either component. The method is currently being used to support Phase I kinetics program for rifabutin in prophylaxis of MAC infection of AIDS patients. Application of this method to a bioavailability assessment is presented.     

Determination of Clarithromycin as a Contaminant on Surfaces by High-Performance Liquid Chromatography Using Electrochemical Detection

Microgram levels of clarithromycin residues on various surfaces are quantitated. After cleaning, any residual clarithromycin remaining is removed from the surface by a wet swab–dry swab technique. High-performance liquid chromatography with electrochemical detection is used for quantitation of the resulting solutions. Recoveries ranged from 93 to 118%.     

Development and Validation of a RP-HPLC Method for Estimation of Prulifloxacin in Tablet Dosage Form

A simple, precise, rapid, accurate and economic reverse phase high performance liquid chromatographic method has been developed for the estimation of prulifloxacin in tablet dosage form. The separation was achieved by using octadecylsilane column (C(18)) and KH(2)PO(4) buffer: acetonitrile adjusted to pH 7.3 with triethyl amine in proportion of 10:90 v/v as mobile phase, at a flow rate of 1.0 ml/min. The detection was carried out at 278 nm. The retention time of prulifloxacin was found to be 2.4 min. The limit of detection and limit of quantitation were found to be 0.14 μg/ml and 0.42 μg/ml respectively. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity, precision, accuracy and specificity according to ICH guidelines. The proposed method provides an accurate and precise quality control tool for routine analysis of prulifloxacin in tablet dosage form.     

Development and Validation of Liquid Chromatography Method for Quantification of the Active Markers of Hintonia standleyana. and Hintonia latiflora. Crude Drugs

Abstract

The infusions prepared from the stem-bark of Hintonia latiflora. (Sesse et Mociño ex DC) Bullock or Hintonia standleyana. Bullock (Rubiaceae) are indistinctly used in Mexican traditional medicine for the treatment of non–insulin-dependent diabetes mellitus and malaria fevers. Suitable high-performance liquid chromatography (HPLC)-UV methods for quantitative determination of 5-O.-[β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyl]-7-methoxy-3′,4′-dihydroxy-4-phenylcoumarin (1) and 5-O.-[β-d-xylopyranosyl-(1 → 6)-β-d-glucopyranosyl]-7-methoxy-3′,4′-dihydroxy-4-phenylcoumarin (2) in the infusions of H. standleyana. and H.. latiflora., respectively, were established. Coumarins 1 and 2 are the major antihyperglycemic compounds found in the infusions prepared from stem-bark of H. standleyana. and H.. latiflora., respectively, and are proposed as the active markers. The methods were found to be reliable, reproducible, and accurate.     

Development and Validation of a Reversed-phase HPLC Method for the Determination of Hydroxybenzene in a Cream Formulation

A rapid, sensitive and specific reversed-phase high performance liquid chromatographic method with diode-array detection has been developed and validated for the determination of hydroxybenzene (0.494%, w/w) in a commercially available cream pharmaceutical formulation. Isocratic chromatography was performed on a C18 column with methanol-water 60:40 (v/v) containing 0.1% phosphoric acid (v/v) as mobile phase at a flow rate of 1.0 ml/min. UV detection was at 254 nm. Linearity of the method was excellent (r(2) = 0.9999). The relative standard deviation values for intra- and inter-day precision studies were < 1% and the recovery of hydroxybenzene was >99%. The limit of detection and quantitation for hydroxybenzene was found to be 13.5 η g/ml and 2 μg/ml, respectively. The method was also validated for specificity and robustness. The method was found to be robust and can be reliably used to determine the hydroxybenzene content of marketed formulations.     

Development and Validation of a RP-HPLC Method for Estimation of Montelukast Sodium in Bulk and in Tablet Dosage Form

The present work describes a simple, precise and accurate HPLC method for estimation of montelukast sodium in bulk and in tablet dosage form. The separation was achieved by using octadecylsilane column (C18) and acetonitrile:1 mM sodium acetate adjusted to pH 6.3 with acetic acid in proportion of 90:10 v/v as mobile phase, at a flow rate of 1.5 ml/min. Detection was carried out at 285 nm. The retention time of montelukast sodium was found to be 3.4 min. The limit of detection was found 1.31 µg/ml and limit of quantification 3.97 µg/ml. The accuracy and reliability of the proposed method was ascertained by evaluating various validation parameters like linearity (1-100 µg/ml), precision, accuracy and specificity according to ICH guidelines. The proposed method provides an accurate and precise quality control tool for routine analysis of montelukast sodium in bulk and in tablet dosage form.     

Development and Validation of a RPLC Method for the Determination of 2-Phenoxyethanol in Senselle Lubricant Formulation

A new and simple reversed-phase liquid chromatographic method has been developed and validated for the determination of 2-phenoxyethanol preservative (0.3%, w/w) in senselle lubricant formulation. The separation was achieved with acetonitrile-tetrahydrofuran-water (21:13:66, v/v/v) as mobile phase, a C(8) column, and UV detection at 258 nm. The calibration curve is linear (r(2)= 0.9999) from 20-140% of the analytical concentration of 0.75 mg/ml. The mean percent relative standard deviation values for intra- and inter-day precision studies are <1%. The recovery of 2-phenoxyethanol ranged between 99.76 and 100.03% from lubricant formulation. The limits of detection and quantitation are determined to be 0.094 and 0.15 mg/ml, respectively. The method was found to be robust and can be successfully and reliably used to determine the 2-phenoxyethanol preservative content of marketed formulations.     

A Reversed-Phase High-Performance Liquid Chromatographic (HPLC) Assay for the Determination of Biotin in Multivitamin–Multimineral Preparations

Pharmaceutical Research -     

兔血浆中地非三唑(DL111-IT)高效液相色谱荧光检测方法

目的　建立兔血浆中DL111 IT的高效液相色谱荧光检测法。方法　血浆样品和内标格列本脲经氯仿提取后 ,选用DiamonsilODS C18柱 (15 0mm× 4 . 6mm ,5 μm) ,乙腈 - 0 . 0 2 5mol·L-1磷酸氢二铵缓冲溶液 (磷酸调pH 5 .0 ) (6 0 .4 0 ,V/V)为流动相 ,流速 1 0mL·min-1,荧光检测 (λex=2 5 0nm ,λem=332nm)。结果　DL111 IT在浓度 1 .0 0～ 2 0. 0 0ng·mL-1范围内呈良好线性 ,r=0. 9996 ,n =5。高 (2 0 . 0 0ng·mL-1)、中 (10 . 0 0ng·mL-1)、低 (1 .0 0ng·mL-1) 3个质控样本平均提取回收率分别为85 . 3%± 1 .3% ,84 .9%± 2 . 7% ,85 . 8%± 1 .8% ,方法回收率分别为 99 .5 %± 0 . 4 % ,10 2 . 1%± 1. 8% ,10 .1 3%± 2 .4 % ;日内(n =5 )和日间 (n =5 )RSD分别低于 3 .0 %和 7. 0 %。血浆样品检测限为 0 3ng·mL-1(S/N =3) ,定量限为 1ng·mL-1(S/N =10 ,RSD <7 .0 % )。结论　本法准确、灵敏、操作简便 ,为DL111 IT药代动力学研究提供了方法学基础。     

Validation of a Column-Switching High-Performance Liquid Chromatographic (HPLC) Method for Determination of ML-1035 and Its Five Metabolites in Plasma

A fully automated column-switching HPLC procedure has been developed and validated for quantitation of ML-1035 and its five metabolites in plasma employing direct injection. Plasma samples were injected onto a CN extraction column (4 × 4.6 mm, 5 µm) for micellar cleanup with 0.5% sodium dodecyl sulfate (SDS) in 50 mM phosphate. The proteinaceous components were solubilized and flushed out. The extracted compounds were then eluted by forward flush onto a C₈ analytical column (150 × 4.6 mm, 5 µm) for further analysis using fluorescence detection (excitation, 308 nM; emission, 350 nm). After the subsequent washing and reequilibration with a sequence of three solvent mixtures, the extraction column was ready for the next injection. The limit of quantitation for all compounds of interest was about 10 to 15 ng/ml using 100 µl of plasma. Excellent precision, accuracy, and linearity were obtained for all compounds over a range of 10 to 1500 ng/ml. The practicality of the HPLC method was also validated with plasma samples from dogs receiving ML-1035. Longevity for both extraction and analytical columns is excellent. Micellar cleanup coupled with the column-switching technique is a promising HPLC procedure when using direct injection of biological fluids.     

刺五加制剂用固相萃取后以高效液相色谱法测定刺五加苷B、苷E的含量

目的用高效液相色谱法研究刺五加制剂中2个主要活性成分刺五加苷B、苷E的含量测定方法.方法 Kromasil ODS柱, 水-乙腈梯度流动相, 流速0.8 mL·min-1, 测定波长刺五加苷B 206 nm,刺五加苷E 220 nm, 水杨酸作为内标, 选择了固相萃取条件.结果刺五加片中刺五加苷B、苷E的回收率范围分别是90.4%～96.8%和87.7%～93.3%;刺五加注射液中刺五加苷B、苷E的回收率范围分别是96.4%～99.8%和95.7%～98.5%.线性范围分别是4.45～22.25 μg·mL-1(r=0.999 8)和5.11～25.55 μg·mL-1(r=0.999 7).结论该方法节约了清洗色谱系统的时间, 提高了测定的灵敏度,提供了评价刺五加制剂质量的方法.     

A Sensitive and Specific Procedure for Quantitation of ADR-529 in Biological Fluids by High-Performance Liquid Chromatography (HPLC) with Column Switching and Amperometric Detection

An HPLC method using electrochemical detection (ED) has been validated for the determination of ADR-529 in plasma and urine using ICRF-192 as an internal standard (IS). Prior to storage and quantitation, both plasma and urine samples require acid stabilization. Acidified plasma samples were prepared for HPLC using a two column solid-phase extraction (SPE). An aliquot of buffered plasma (i.e., pH 6-7) was first deproteinated and desalted on a C-18 SPE column. The analytes were then eluted onto a C-8 SPE column where retention and selective cleanup were achieved in the cation-exchange mode via silanol interactions. Acidified urine samples were diluted in acetonitrile prior to injection. The HPLC system for plasma and urine samples employed two narrow-bore silica columns used in the weak cation-exchange mode and separated by a switching valve. To prohibit late-eluting peaks from passivating the glassy carbon working electrode, a heart-cut containing ADR-529 and the IS was vented from the first silica column to the second using an automated switching valve. Amperometric detection at an oxidation potential of +1050 mV vs a Ag/AgNO₃ reference electrode was used. Linearity was validated between 5 and 500 µg/ml in plasma and between 2 and 100 µg/ml in urine. Imprecision and percentage bias were typically <10% for both plasma and urine controls throughout their respective dynamic ranges. The absolute recoveries for ADR-529 and the IS from plasma were >95%. This method is being successfully applied to the pharmacokinetic/dynamic evaluation of ADR-529 in animals and humans.     

A Targeted UHPLC-MS/MS Method Validated for the Quantification of Ergot Alkaloids in Cereal-Based Baby Food from the Belgian Market

Following pending new legislation in the European Union setting a maximum of 20 ng g⁻¹ for the total sum of ergot alkaloids in dry cereal-based baby food, a new UHPLC-MS/MS method was developed. It is suitable for the quantification of six ergot alkaloids: Ergocornine, ergocristine, ergometrine, ergosine, ergotamine, α-ergocryptine, and their corresponding epimers. The method is able to reliably detect individual ergot alkaloids at a level as low as 0.5 ng g⁻¹. The method uses a modified QuEChERS extraction approach before UHPLC-MS/MS analysis. The method showed good sensitivity, accuracy, and precision. It has been applied to 49 samples from the Belgian market. In 26 samples, not a single ergot alkaloid was detected while in 23 out of 49 samples at least one ergot alkaloid was detected with 2 samples containing 12 ergot alkaloids. Ergometrine was the alkaloid most frequently detected i.e., 16 out of 49 samples. Only one sample, testing positive for all 12 ergot alkaloids, would be non-conforming to the newly proposed Maximum Residue Level (MRL).     

Analysis of the Antimalarial Sesquiterpene Artemisinin in Artemisia annua by High-Performance Liquid Chromatography (HPLC) with Postcolumn Derivatization and Ultraviolet Detection

Pharmaceutical Research -     

Method for the Determination of Diphenhydramine in Rabbit Whole Blood by High-Performance Liquid Chromatography (HPLC) with Ultraviolet (UV) Detection in Conjunction with Gas Chromatography (GC) with Mass Selective Detection (MSD)

An HPLC/GC-MSD method for the determination of diphenhydramine in rabbit whole blood has been developed and validated. This method is based on a liquid–liquid extraction and reversed-phase Chromatography with ultraviolet absorbance detection monitored at 258 nm. HPLC eluant fractions containing diphenhydramine and the internal standard, orphenadrine, were collected, reex-tracted, then subjected to GC-MSD analysis. Whole blood was utilized, thereby decreasing the required sample volume and increasing the sensitivity of the assay. Diphenhydramine concentrations can be quantitated over a range of 1 to 1000 ng/ml whole blood.     

Determination of Urinary 8-Hydroxydeoxyguanosine by Coupled-Column High-Performance Liquid Chromatography with Electrochemical Detection: A Noninvasive Assay for in Vivo Oxidative DNA Damage in Humans

Oxidative damage to DNA has been suggested to contribute to a number of diseases including cancer and chronic inflammation. In order to study the relationship between oxidative damage to DNA and diseases, it is desirable to develop techniques that can be used for the analysis of DNA damage products in individuals. The present article describes a sensitive analytical method for determination of the oxidative DNA adduct, 8-hydroxydeoxyguanosine (80HdG) in human urine, based on coupled-column high-performance liquid chromatography with electrochemical detection. The method measures down to 2 nmol 80HdG/L urine, which is well below the levels of 80HdG in normal human urine (5–15 nmol/L). It is shown that smokers excrete slightly more 80HdG in their urine than nonsmokers and that patients undergoing radiotherapy or chemotherapy for different malignant diseases excrete significantly more than healthy individuals. The potential use of the method for detecting increased urinary 80HdG excretion and conditions associated with increased oxidative DNA damage in humans is discussed. It is suggested that the assay could be used to detect damage resulting from the exposure of an individual to foreign compounds that stimulate production of reactive oxygen metabolites, and that it could be used to investigate conditions with high rates of DNA damage and repair. Furthermore, the assay may be used to compare 80HdG excretion before and after various types of antioxygen treatment and so help to identify treatments that protect human beings from oxidative DNA damage.     

Development and Validation of a Dissolution Test for Meloxicam and Pridinol Mesylate from Combined Tablet Formulation

The association of meloxicam and pridinol is indicated for treating muscular contractures and low back pain. A dissolution test for the meloxicam-pridinol combined tablet formulation was developed and validated, using a suitable HPLC method for simultaneously quantitating both dissolved drugs. The optimized conditions include the use of USP apparatus 2 at a paddle rotation rate of 75 rpm and 900 ml of 50 mM phosphate buffer (pH= 7.5) as dissolution medium, at 37.0±0.5°. The test, which demonstrated to be robust against small changes in bath temperature, paddle rotation speed and pH of the dissolution medium, was applied to two different brands of tablets; the corresponding dissolution profiles were constructed and both brands showed to dissolve at least 75% of the drugs at the 45 min time point.     

薄性康药膜微生物限度检查方法的建立和验证

建立薄性康药膜的微生物限度检查方法。按照《中国药典》2005版微生物限度检查方法进行验证试验。该药膜的细菌计数方法为培养基稀释法;霉菌及酵母菌计数方法为平皿法;金黄色葡萄球菌和铜绿假单胞菌可采用常规法检验。     

Development and Validation of a RP-Ultra performance liquid chromatographic Method for Quantification of Topotecan Hydrochloride in Bulk and Injection Dosage Form

A simple, very fast, precise and accurate reverse phase ultra performance liquid chromatographic method was developed for the determination and validation of topotecan hydrochloride in bulk and injection dosage form. A Waters BEH C18, 50×2.1 mm, 1.7 μm particle size column in gradient mode was used with mobile phase comprising of 0.1% v/v orthophosphoric acid in water and acetonitrile. The analytical column was thermostated at 50° and flow rate was set at 0.4 ml per min, with photo diode array detection at 260 nm. The retention time of topotecan was found 1.38 min. The method was validated in terms of linearity, accuracy, precision and specificity. The calibration curve was found linear between 20 to 60 μg/ml. The limit of detection and limit of quantification were found 0.2353 and 0.7131 μg/ml, respectively. Percentage recoveries were obtained in the range of 98.91% and 99.17%. The proposed method is precise, accurate, selective and reproducible. The ultra performance liquid chromatographic assay procedure, which proved superior because of its greater sensitivity and relatively shorter (4 min) run time, should be an important tool for speedy future analysis of topotecan hydrochloride in bulk and its injection dosage form.