μBondapak Phenyl Column Research Articles

Liquid Chromatographic Assay for Salicylic Acid in Liquid and Semisolid Formulations

Abstract A high performance liquid chromatographic assay for quantitating salicylic acid (S) in lotion, collodion, ointment and cream formulations is described. The method involved direct determination of S in the liquid dosage forms after appropriate dilutions with the mobile phase. Prior extraction of S from ointments and creams was carried by chloroform. Metronidazole was used as the internal standard and a μ-Bondapak phenyl column with a mobile phase made of 30%, methanol in 5 mM solution of tetrabutylammonium phosphate (pH 7.5) led to an efficient separation. Retention times of about 3 and 7.5 min were obtained for the internal standard and S respectively. The recovery of S from the dosage forms was tested by adding known amounts of S to each preparation and mixing before determination. The mean percentage recovery was in the range of 98–101.1%. The method was found to be accurate, simple and reproducible.

Application of a bonded-phase extraction column for rapid sample preparation of flecainide from human plasma for high-performance liquid chromatographic analysis--fluorescence or ultraviolet detection.

A simple, rapid, selective, and sensitive procedure for the monitoring of flecainide levels in human plasma is described. The drug and the internal standard--a positional isomer of flecainide--are separated from plasma by the use of a disposable extraction column packed with reversed-phase sorbent. The drug and internal standard which are selectively retained on the extraction column are eluted. An aliquot is injected onto a mu-Bondapak phenyl column and eluted with a mixture of acetonitrile and 0.06% phosphoric acid (40:60, vol/vol) at a flow rate of 2 ml/min. The eluted drug and internal standard are measured by a fluorescence detector with excitation and emission wavelengths of 300 and 370 nm, respectively. The linear range is 3-2,000 ng/ml, and the sensitivity limit is 3 ng/ml with 1 ml of plasma. The within-day coefficient of variation was 1.1-4.6% at concentrations ranging from 3 to 1,600 ng/ml. Many drugs given concomitantly with flecainide acetate do not interfere with the assay. The method compares favorably to a well-documented gas-liquid chromatographic method and is suitable for use in plasma drug level monitoring for patient management as well as in pharmacokinetic studies. Similar results were obtained using an alternate detection method (ultraviolet detection at 298 nm).

Rapid determination of tetracycline and lumecycline in human plasma and urine using high-performance liquid chromatography

A rapid and accurate method for the determination of tetracycline in human plasma and urine is presented. Determination of tetracycline in plasma is based on precipitation of plasma proteins with trifluoroacetic acid, followed by injection of the centrifuged plasma sample onto a μBondapak C 18 column. Acetonitrile in phosphate buffer pH 2.2 is used as mobile phase. Only tetracycline, and no trace of lumecycline can be detected in plasma and urine after administration of lumecycline, indicating that lumecycline is completely degraded to tetracycline, lysine and formaldehyde in the gastrointestinal tract prior to absorption. Determination of tetracycline in urine was performed by injection of urine diluted with phosphoric acid onto a μBondapak Phenyl column. The precision of determination of tetracycline in plasma, expressed as the relative standard deviation, was < 3% at tetracycline concentrations of 0.05 and 3.7 μg/ml. Urine determinations were made with a precision of < 1.5% at tetracycline concentrations of 0.5 and 6.7 μg/ml.

Determination of amdinocillin in plasma and urine by high-performance liquid chromatography

A rapid, sensitive and specific high-performance liquid chromatographic (HPLC) assay was developed for the determination of amdinocillin (formerly mecillinam) in human plasma and urine. The assay is performed by direct injection of a plasma protein-free supernatant or a dilution of urine. A 10-μm μBondapak phenyl column with an eluting solvent of water—methanol—1 M phosphate buffer, pH 7 (70:30:0.5) was used, with UV detection of the effluent at 220 nm. Azidocillin potassium salt [potassium-6-( d-(-)-α-azidophenyacetamido)-penicillanate] was used as the internal standard and quantitation was based on peak height ratio of amdinocillin to that of the internal standard. The assay has a recovery of 74.4 ± 6.3% (S.D.) in the concentration ranges of 0.1–20 μg per 0.2 ml of plasma with a limit of detection equivalent to 0.5 μg/ml plasma. The urine assay was validated over a concentration range of 0.025–5 mg/ml of urine, and has a limit of detection of 0.025 mg/ml (25 μg/ml) using a 0.1-ml urine specimen per assay. The assay was applied to the determination of plasma and urine concentrations of amdinocillin following intravenous administration of a 10 mg/kg dose of amdinocillin to two human subjects. The HPLC and microbiological assays were shown to correlate well for these samples.

Reverse-phase high-performance liquid chromatographic separation and electrochemical detection of norepinephrine, dopamine, serotonin, and related major metabolites

A convenient method for the determination of biogenic amines and their metabolites in small samples of brain tissue weighing from 0.5 to 5 mg, based on reverse-phase chromatography, is described. The biogenic amines, norepinephrine, dopamine, and serotonin, and the metabolites normetanephrine and 3-methoxytyramine were separated by ion-pair chromatography on a μBondapak phenyl column with an aqueous eluant, while the metabolites 3,4-dihydroxyphenylacetic acid, homovanillic acid, 3-methoxy-4-hydroxyphenylglycol, and 5-hydroxyindoleacetic acid were separated on a μBondapak C18 column with a methanol aqueous mobile phase. The sensitivity of the method is in the picogram range, from 20 to 100 pg, depending on the substances analyzed.

High Pressure Liquid Chromatographic Determination of Mecillinam in Human Plasma and Urine

Abstract A simple, specific, rapid and sensitive method for the analysis of mecillinam in plasma and urine using high pressure liquid chromatography is described. The assay is performed by direct injection of a plasma protein free supernatant or a dilution of urine. A μBondapak phenyl column with an eluting solvent of 16% CH3CN-0.2% H3PO4 was used, with UV detection of the effluent at 220 nm. Desacetyl-cephalothin was used as the internal standard and quantitation was based on peak height ratio of mecillinam to that of the internal standard. The lowest concentration detectable without extraction was 0.25 μg/ml for plasma and 8.9 μg/ml for urine. No interference from plasma and urine was noted.

Detection of the amine derivative of misonidazole in human urine by high-pressure liquid chromatography

A sensitive high-pressure liquid chromatographic assay for the detection and quantitation of the amine derivative of misonidazole in human urine is reported. The amine was converted to its dansyl derivative and was separated on a reverse-phase μBondapak phenyl column. Absorbance at 365 nm was monitored for the detection of the dansyl derivative. Using this procedure, the amine derivative has been identified as a urinary metabolite of misonidazole.

Quantitative Determination of Guaifenesin, Phenylprolamine Hydrochloride Sodium Benzoate Δ Codeine Phosphate in Cough Syrups by High-Pressure Liquid Chromatography

Abstract A rapid Paired-ion high-pressure liquid chromatographic method for the quantitative determination of guaifenesin, phenylpropanolamine hydrochloride, sodium benzoate and codeine phosphate in cough syrups was developed. Heptane sulfonic acid was used as a counter-ion in the mobile phase. A fixed wavelength detector (λ = 254 nm) and a μ-Bondapak phenyl column was employed. Total analysis time for all the active ingredients was 22 minutes.

Analysis of Hydroxybenzoic Acids by High Pressure Liquid Chromatography

Abstract Good separation of a range of hydroxybenzoic acids was achieved by HPLC on a μBondapak phenyl column using 5% v/v acetic acid in water as the eluting solvent.