Simultaneous determination of seven phthalates and four parabens in cosmetic products using HPLC-DAD and GC-MS methods

Studies on the determination of seven kinds of phthalates, i.e. diethyl phthalate, dipropyl phthalate, dibutyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate, di-(2-ethylhexyl) phthalate, and dioctyl phthalate, and four parabens, i.e. methylparaben, ethylparaben, propylparaben, and butylparaben, in 15 kinds of cosmetic products, including hair sprays, perfumes, deodorants, cream, lotion, etc., by HPLC with diode array detection and GC-MS in electron impact ionization mode with selected-ion monitoring have been carried out. Methods have been developed for both qualitative and quantitative detection of phthalates and parabens. Extraction, clean-up, and analysis procedures have been optimized. HPLC and GC-MS determinations were performed after sonication-assisted extraction with methanol and clean-up with C18 SPE. These techniques permit detection of phthalates at a level of 10.0-100.0 microg/kg and of parabens at a level of 20.0-200.0 microg/kg. Overall recoveries were 85-108% with RSD values of 4.2-8.8%. Only one of the 15 examined samples was free from phthalates and parabens. The remaining 14 samples were found to contain at least three or more of these phthalates and/or parabens. The predominant phthalates and parabens detected in the studied samples were methylparaben, propylparaben, diethyl phthalate, dibutyl phthalate, dicyclohexyl phthalate, and di-(2-ethylhexyl) phthalate. The residue level is at 1.22-5289 mg/kg.     

Capillary gas-chromatographic determination of spermidine in hair lotion

Biogenic polyamines, such as spermidine (SPD, NH2-(CH2)4-NH-(CH2)3-NH2), are ubiquitous polycationic molecules which play a definitive role in many biological processes such as nucleic acid metabolism, protein synthesis, and cell growth. SPD is commonly used as an ingredient in hair lotions, because it seems to promote hair growth. This work describes a capillary GC method for quantitative determination of SPD in hair lotions using 1,6-diaminohexane as internal standard, a methyl silicone capillary column, and a flame ionisation detector. Aliquots of hair lotion were treated with an alkaline aqueous solution and internal standard was added. The emulsion was extracted with diethyl ether containing ethyl chloroformate. Ether extracts, evaporated to dryness and reconstituted in ethyl acetate, were analysed by capillary GC with flame ionisation detection. Validation took into account the specificity, linearity, precision, and accuracy of the analytical method: these parameters were valid for the quantitative determination of SPD in hair lotion.     

HPLC determination and pharmacokinetics of osthole in rat plasma after oral administration of Fructus Cnidii extract

A simple and sensitive high-performance liquid chromatographic (HPLC) method is developed for the determination of osthole in rat plasma and applied to a pharmacokinetic study in rats after administration of Fructus Cnidii extract. After addition of fluocinonide as an internal standard, plasma samples are extracted with diethyl ether. HPLC analysis of the extracts is performed on a Hypersil ODS2 analytical column, using methanol-0.4% acetic acid (65:35, v/v) as the mobile phase. The UV detector is set at 322 nm. The standard curve is linear over the range 0.0520-5.20 microg/mL (r = 0.9979). The mean extraction recoveries of osthole at three concentrations were 81.0%, 91.2%, and 90.7%, respectively. The intra- and interday precisions have relative standard deviations from 1.9% to 4.9%. The limit of quantitation is 0.0520 microg/mL. The HPLC method developed can easily be applied to the determination and pharmacokinetic study of osthole in rat plasma after the animals are given the Fructus Cnidii extract. The plasma concentration of osthole from six rats showed a Cmax of 0.776 +/- 0.069 microg/mL at Tmax of 1.0 +/- 0.3 h.     

An effective high-speed countercurrent chromatographic method for preparative isolation and purification of mollugin directly from the ethanol extract of the Chinese medicinal plant Rubia cordifolia

The medicinal plant Rubia cordifolia has been used widely in traditional Chinese medicine (TCM) for its antibacterial, antioxidant and anti-inflammatory activities. In this study, a preparative high-speed countercurrent chromatography (HSCCC) method for isolation and purification of the bioactive component mollugin directly from the ethanol extract of R. cordifolia was successfully established by using light petroleum (bp 60-90 degrees C)/ethanol/diethyl ether/water as the two-phase solvent system. The upper phase of light petroleum/ethanol/diethyl ether/water (5:4:3:1 v/v) was used as the stationary phase of HSCCC. Under the optimum conditions, 46 mg of mollugin at 98.5% purity, as determined by HPLC, could be yielded from 500 mg of the crude extract in a single HSCCC separation. The peak fraction of HSCCC was identified by 1H NMR and 13C NMR.     

Determination of low molecular weight alcohols including fusel oil in various samples by diethyl ether extraction and capillary gas chromatography

Low molecular weight alcohols including fusel oil were determined using diethyl ether extraction and capillary gas chromatography. Twelve kinds of alcohols were successfully resolved on the HP-FFAP (polyethylene glycol) capillary column. The diethyl ether extraction method was very useful for the analysis of alcohols in alcoholic beverages and biological samples with excellent cleanliness of the resulting chromatograms and high sensitivity compared to the direct injection method. Calibration graphs for all standard alcohols showed good linearity in the concentration range used, 0.001-2% (w/v) for all alcohols. Salting out effects were significant (p < 0.01) for the low molecular weight alcohols methanol, isopropanol, propanol, 2-butanol, n-butanol and ethanol, but not for the relatively high molecular weight alcohols amyl alcohol, isoamyl alcohol, and heptanol. The coefficients of variation of the relative molar responses were less than 5% for all of the alcohols. The limits of detection and quantitation were 1-5 and 10-60 microg/L for the diethyl ether extraction method, and 10-50 and 100-350 microg/L for the direct injection method, respectively. The retention times and relative retention times of standard alcohols were significantly shifted in the direct injection method when the injection volumes were changed, even with the same analysis conditions, but they were not influenced in the diethyl ether extraction method. The recoveries by the diethyl ether extraction method were greater than 95% for all samples and greater than 97% for biological samples.     

高效液相色谱法同时测定中药材亳菊中多菌灵、吡虫啉和啶虫脒的残留量

建立了同时测定中药材亳菊中多菌灵、吡虫啉和啶虫脒残留量的高效液相色谱分析方法。样品经盐酸溶液超声提取,乙醚除杂,二氯甲烷萃取后,采用ODS柱,以V(乙腈):V(0.1%磷酸,三乙胺调pH至3.6)=14:86为流动相,270nm波长处检测。结果三种农药呈良好的线性关系(r为0.9997、0.9998和0.9999),最低检出浓度分别为0.04,0.02和0.1 mg/kg。方法的平均加标回收率范围分别为:83.8%～101.3%,81.8%～90.8%和83.6%～95.0%,对应的RSD分别为:3.9%～4.3%,2.6%～3.3%和3.5%～5.9%。方法能够满足多菌灵、吡虫啉和啶虫脒在中药材亳菊中残留分析的要求。     

High-pressure liquid chromatography combined with fluorescence detection and solvent extraction for simultaneous determination of coproporphyrins I and III in human urine

A precise and reproducible high-pressure liquid chromatography (HPLC) method for the determination of coproporphyrin I and III isomers (cp isomers) in urine was investigated. The cp isomers were extracted into diethyl ether, the solution was evaporated and the residue dissolved prior to HPLC. The recoveries of both cp isomers were 87.8 +/- 3.2 and 90.0 +/- 2.1% and detection limits (S/N = 3) were 0.07 ng, respectively.     

High-performance liquid chromatographic method for simultaneous determination of enantiomers of 5-dimethylsulphamoyl-6,7-dichloro-2-dihydrobenzofuran-2, carboxylic acid and its N-monodemethyl metabolite in monkey plasma and urine after chiral derivatization

A quantitative method for the simultaneous high-performance liquid chromatographic (HPLC) resolution and determination of the enantiomers of 5-dimethylsulphamoyl-6,7-dichloro-2,3-dihydrobenzofuran-2-carboxyl ic acid, a new diuretic, and its N-monodemethylated metabolite in monkey plasma and urine is described. The method includes diethyl ether extraction of the samples and S-(-)-alpha-methylbenzylamide derivatization of the extract, followed by reversed-phase solid-phase extraction and injection of the resulting diastereoisomers onto a reversed-phase HPLC column. Baseline separation was obtained. The assay showed linearity over the range 0.1-50 micrograms/ml of plasma and 0.25-500 microliters of urine, with a lower limit of detection of ca. 0.01 micrograms/ml for each of the enantiomers. The method is adequate for pharmacokinetic and enantioselective disposition studies of both the diuretic and its metabolite.     

Sensitive high-performance liquid chromatographic determination of famotidine in plasma. Application to pharmacokinetic study.

A sensitive high-performance liquid chromatographic (HPLC) method for the quantitation of famotidine in human plasma is described. Clopamide was used as the internal standard. Plasma samples were extracted with diethyl ether to eliminate endogenous interferences. Plasma samples were then extracted at alkaline pH with ethyl acetate. Famotidine and the internal standard were readily extracted into the organic solvent. After evaporation of ethyl acetate, the residue was analysed by HPLC. The chromatographic separation was accomplished with an isocratic mobile phase consisting of acetonitrile-water (12:88, v/v) containing 20 mM disodium hydrogenphosphate and 50 mM sodium dodecyl sulphate, adjusted to pH 3. The HPLC microbore column was packed with 5 microns ODS Hypersil. Using ultraviolet detection at 267 nm, the detection limit for plasma famotidine was 5 ng/ml. The calibration curve was linear over the concentration range 5-500 ng/ml. The inter- and intra-assay coefficients of variation were found to be less than 10%. Applicability of the method was demonstrated by a bioavailability/pharmacokinetic study in normal volunteers who received 80 mg famotidine orally.     

HPLC determination of imidazole antimycotis in antidandruff cosmetic products.

A simple HPLC method for the determination of imidazole antimycotics in cosmetic antidandruff formulations has been developed. HPLC was carried out on a Discovery RP-Amide C16 column and spectrophotometric detection was performed at 220 nm. The initial mobile phase was a mixture of acetonitrile and aqueous 10(-3) M NaClO4 (pH 3.0) in the ratio of 15:85 (v/v); then a linear gradient up to 46% acetonitrile in 70 min, and up to 50% in 80 min. The extraction procedure has been validated by analyzing samples of shampoo and lotion spiked with 1% of the active principles. The recoveries were greater than 95% and the reproducibility was within 3%.     

高效液相色谱法测定人血清中阿西美辛和吲哚美辛

摘要：建立了测定人血清中阿西美辛及其活性代谢物吲哚美辛的高效液相色谱法。分析柱为Spherisorb-C8（5μm）,4.6mm×250mm,流动相为V（醋酸盐缓冲液,pH4.6）:V（乙腈）:V（甲醇）=55:40:5,流速1.0mL/min,检测波长254nm。血清中药物质量浓度为12.5μg/L～1.6mg/L时,阿西美辛、吲哚美辛峰高与内标甲苯磺丁脲峰高比值和质量浓度呈良好的线性关系;阿西美辛日内、日间变异系数分别为3.6％和5.6％,平均回收率为78.3％;吲哚美辛日内、日间变异系数分别为2.4     

High performance liquid chromatographic determination of metoclopramide in plasma and urine and its application to biopharmaceutical investigations

An optimized HPLC method for the quantification of metoclopramide (MCP) in human plasma and urine is described. MCP and internal standard are extracted from alkalinized substrate into diethyl ether and back-extracted into dilute acid. The analytes are separated with a ternary mobile phase at cyanopropyl-silica and detected at 312 nm (UV detection). The lower limit of quantification is 0.5 ng/ml in plasma and 50 ng/ml in urine. Optimization of extraction, chromatography, and detection is discussed. The method is selective to numerous common drug substances with excellent accuracy and precision data. After validation, the method is applied to the samples of a pharmacokinetic study. Pharmacokinetic parameters indicate the need for a sophisticated method as tool for optimization of metoclopramide formulations.     

Determination of cyclosporin A in the serum of kidney transplant patients by rapid-flow fractionation and normal-phase high-performance liquid chromatography

High-performance liquid chromatography was used to determine cyclosporin A (CsA) concentrations in the serum of kidney transplant patients by rapid-flow fractionation (RFF) followed by silica gel normal-phase high-performance liquid chromatography (HPLC). The extraction of CsA from serum was achieved by RFF using a short diatomaceous earth column eluted with diethyl ether-n-hexane (50:50, v/v). The recovery was more than 80% at concentrations of 50-150 micrograms/l. The concentration of this compound was determined by HPLC using a conventional silica gel column with 3.3 M ammonia solution-ethanol-n-hexane (0.31:10.69:89, v/v) as eluent. Concentration calibration was made on the basis of the peak-height ratio of CsA to CsD as the internal standard. The coefficient of variation of this assay was less than 6.5% and the results were used for the therapeutic drug monitoring of CsA administered to kidney transplant patients. Measurements of the CsA concentrations in 160 serum specimens were also made by conventional radioimmunoassay (RIA) using commercial kits. The data obtained by RIA were on average 2.5 times those obtained by HPLC. Higher values in RIA were observed characteristically with patients with severe disfunction resulting from CsA hepatotoxicity. From the results, it appeared that HPLC rather than RIA provides more precise and reliable values for the concentration of this drug.     

高效液相色谱法测定血浆中莲心碱的浓度

采用高效液相色谱法（甲基莲心碱为内标）测定了血浆中莲心碱的浓度。以ＵｌｔｒａｓｐｈｅｒｅＳｉ为固定相、二氯甲烷－异丙醇－二乙胺（７５１５０．２,Ｖ／Ｖ）为流动相,检测波长为２８２ｎｍ。血样用氨－氯化铵缓冲液调ｐＨ１０后用乙醚提取。平均回收率９３．６％,ＲＳＤ为１．９％,最低检测浓度０．０２５ｍｇ／Ｌ。     

HPLC determination and pharmacokinetic study of tenatoprazole in dog plasma after oral administration of enteric-coated capsule

A simple, sensitive and selective high-performance liquid chromatographic (HPLC) method with UV detection (306 nm) was developed and validated for determination of tenatoprazole, a novel proton-pump inhibitor, in dog plasma. Tenatoprazole and internal standard (pantoprazole) were extracted into diethyl ether and separated using an isocratic mobile phase of 10 mm phosphate buffer (pH4.7)-acetonitrile (70:30, v/v) on a Diamonsil C(18) column (150 x 4.6 mm, 5 microm). The retention times for tenatoprazole and internal standard were 7.1 and 12.3 min, respectively. No endogenous interferences were observed. This HPLC method was fully validated. The lower limit of quantitation was 20 ng/mL, with a relative standard deviation of less than 20%. A linear range of 0.02-5.0 microg/mL was established. The interday and intraday precisions were within RSD 13.4-10.1 and 4.6-1.4%, respectively. This method developed can be easily applied to the pharmacokinetic study of tenatoprazole in dog plasma after oral administration of an enteric-coated capsule. The plasma concentration of tenatoprazole from six dogs showed a mean C(max) of 2.63 microg/mL at T(max) of 1.89 h. The bioavailability of tenatoprazole was improved by administration of enteric-coated capsule.     

Single-run analysis of retinal isomers, retinol and photooxidation products by high-performance liquid chromatography

A high-performance liquid chromatographic (HPLC) procedure was developed to allow the rapid separation, in a single run, of a mixture of the main retinal isomers (all-trans, 13-cis, 9-cis), all-trans-retinol, and of the two major photooxygenated photoproducts (5,8-peroxyretinal and 5,6-epoxyretinal). The mixture was separated by HPLC on an octadecyl (ODS) column with 16% (v/v) diethyl ether in hexane as mobile phase and anthracene as the internal standard. A commercial type cosmetic formulation containing 0.05% all-trans-retinal was analyzed successfully for this analyte.     

High-performance liquid chromatographic determination of cicletanide, a new diuretic, in plasma, red blood cells, urine and saliva

A sensitive, selective and easy to use high-performance liquid chromatographic method for the determination of cicletanide, a new diuretic, in plasma, red blood cells, urine and saliva is described. After extraction of cicletanide together with an internal standard with diethyl ether, or diethyl ether-n-hexane (20:80) for urine, the sample extracts are chromatographed with water-methanol-acetic acid (50:50:0.3) as eluent on to a Nucleosil C18 column. Both compounds are detected by their ultraviolet absorption at 280 nm. The calibration graph was linear between 0.2 and 20 micrograms/ml for plasma and between 0.2 and 5 micrograms/ml for the other biological fluids. The sensitivity limit was 20 ng/ml for plasma, red blood cells and saliva and 30 ng/ml for urine. The coefficients of variation of the between-day assays did not exceed 4.6% in plasma, 8.3% in red blood cells, 7.8% in urine and 4.2% in saliva for the lowest concentrations studied. The application of the method to a pharmacokinetic study of cicletanide after a single oral therapeutic dose in humans is reported.     

Determination of plasma lactic acid concentration and specific activity using high-performance liquid chromatography.

Assessment of lactate metabolism is of particular interest during exercise and in disease states such as diabetes, shock, and absorptive abnormalities of short-chain fatty acids by the colon. We describe an analytical method that introduces radio-active tracers and high-performance liquid chromatography (HPLC) to simultaneously analyze concentrations and specific activities (SAs) of plasma lactate. The HPLC conditions included separation on a reversed-phase column (octadecylsilane) and an isocratic buffer (30% acetonitrile in water). [3H]Acetate served as an internal standard. Lactate and acetate were extracted from plasma samples with diethyl ether following a pH adjustment to less than 1.0 and back-extracted into a hydrophilic phase with sodium carbonate (2 mM, pH greater than 10.0). Lactate is detected in the ultraviolet range (242 and 320 nm) by derivatization with alpha-bromoacetophenone. Control plasma samples were studied after an overnight fast for precision and analytical recovery. Calibration curves were linear in the range 0.18-6.0 mM (r = 0.92). The precision was 3% and the analytical recovery was 87%. The detection limit of the method was 36 pmol. Determination of lactate metabolism was performed in a patient with chronic congestive heart failure who was administered primed-continuous L-[U-14C]lactate (10 microCi bolus and 0.3 microCi/min continuously) during a 60-min rest period. Mean arterial lactate concentration and SA were 1.69 +/- 0.2 mM and 253.8 +/- 22 dpm/mumol, respectively. Systemic lactate turnover was 25.65 mumol/kg per min. Lactic acid systemic turnover, organ uptake and release rates can be accurately determined by isocratic HPLC.     

Determination of butoxyacetic acid in urine by capillary gas chromatography

Summary A simple, rapid and reliable method is presented for the determination of butoxyacetic acid (BAA), the main metabolite of ethylene glycol monobutyl ether (Butyl Cellosolve). The urine is acidified with hydrochloric acid and passed through a cation-exchange column. BAA which is quantitatively found in the filtrate is subsequently adsorbed on XAD-4 resin. After desorption with diethyl ether an aliquot of the eluate is evaporated in a nitrogen stream and methylated with diazomethane in diethyl ether. A forty-fold enrichment is achieved by this procedure. The gas-chromatographic separation is performed on a 60 m fused silica capillary column DB-1 (100% dimethyl-polysiloxane). Flame ionization is used for detection. Pentoxyacetic acid (PAA) serves as internal standard. The detection limit of BAA in urine is 0.02 mg/l. Linearity has been tested up to 50 mg/l. The losses by the clean-up steps are between 10.0% and 22.7%. The average recovery is 100.9%. Within-series imprecision (n=10) has been determined for three concentrations and ranges between 4.8% and 12.6%.

---

Capillar-gas-chromatographische Bestimmung von Butoxyessigsäure in Harn

     

高效液相色谱法测定化妆品中对羟基苯甲酸酯类防腐剂

A new methodis described for the simultaneous determination of methyl , ethyl,n-propyl and n-butyl p-hydroxybenzoates(parabens)in cosmetics by HPLC. The method is simple, effective and accurate. After parabens are extracted with ethyl alcohol,the clear ethyl alcohol solution is passed through a neutral alununum oxide column to remove co-extracted lipids and pigments. Parabens are determined by reverse-phase HPLC at 254nm.