Diastereospecific HPLC Analysis of the Antiulcer Drug,Enprostil, in a Soft Elastic Gelatin Capsule Formulation

Abstract

Enprostil, an E-type prostaglandin analog, is formulated as a 0.3 mM propylene carbonate solution filled into soft elastic gelatin capsules. A characteristic structural feature of enprostil is the presence of two unresolved chiral centers, yielding a drug molecule that exists as two diastereomeric pairs of enantiomers. This report describes an HPLC method for quantitatively determining the relative amounts of enprostil diastereomers in soft elastic gelatin capsules. Using a Spherisorb ODS 5 μym, 250 × 4.5 mm column and a mobile phase mixture of 59:40:1 methanol:water:tetrahydrofuran separates the enprostil diastereomeric pairs and also resolves the enprostil diastereomers from potential interferences arising from placebo and drug degradation. The method performs well as evidenced by the usual statistical tests for: response linearity, recovery efficiency, precision, and lower quantitation limit. Also, the demonstrated dependence of chromatographic retention on mobile phase composition and system operating parameters defines acceptable operating condition ranges.     

New Validated Methods for the Simultaneous Determination of Two Multicomponent Mixtures Containing Guaiphenesin in Syrup by HPLC and Chemometrics‐Assisted UV‐Spectroscopy

Abstract

High pressure liquid chromatographic (HPLC) and spectrophotometric methods are developed for the determination of two multicomponent mixtures containing guaiphenesin, dextromethorphane hydrobromide, and sodium benzoate together with either phenylephrine hydrochloride, chlorpheniramine maleate, and butylparaben (mixture 1) or ephedrine hydrochloride and diphenhydramine hydrochloride (mixture 2). The HPLC method depended on using an ODS column with mobile phase consisting of acetonitrile ?10 mM potassium dihydrogen phosphate, pH 2.7 (40∶60 v/v) containing 5 mM heptane sulfonic acid sodium salt (for mix 1) and a cyanopropyl column with mobile phase consisting of acetonitrile ?12 mM ammonium acetate, pH 5 (40∶60 v/v) (for mix 2) and UV detection at 214 nm. The cyanopropyl column is much less hydrophobic, less sterically restricted to the penetration of bulky solute molecules into the stationary phase, and has weaker hydrogen‐bond acidity than the ODS column. So the cyanopropyl column is more suitable for separation of components of mix 2. The chemometric‐assisted spectrophotometric method with, principal component regression (PCR) and partial least squares (PLS‐1) was used. For the chemometric method a calibration set of the mixture consisting of each compound in each mixture was prepared in distilled water. The absorbance data in the UV spectra were measured in the spectral region (210–240 or 210–224 nm for mix 1 and mix 2, respectively, as this range provided the greatest amount of information about the two mixture components). The spectrophotometric method does not require a separation step. The proposed methods were successfully applied for the analysis of the two multicomponents combinations in laboratory‐prepared mixtures and in commercial syrups, and the results were compared with each other.     

Determination of Tetracycline and Related Compounds by High-Performance Liquid Chromatography

Abstract

An isocratic high-performance liquid chromatography method for the determination of tetracycline and its related compounds is described. The method uses a reverse phase (C₁₈) column, a modified acetonitrile/water mobile phase, and banzoic acid as the internal standard. Elution of all compounds of interest is complete within seven minutes. Results are presented for thirteen commercial capsule formulations and are compared with results by microbiological assay and thin-layer chromatographic methods.     

Determination of LY217332, A New 3'-Quaternary Ammonium Cephalosporin,In Plasma by Solid Phase Column Extraction and HPLC

Abstract

A sensitive and rapid assay has been developed for the determination of LY217332, a 3'-imidazolo[4,5-c]pyridinium cephalosporin, in plasma. The method utilizes cyano solid phase column extraction and HPLC with ultraviolet detection. The lower limit of detection is 5 ng/ml plasma and the relative standard deviation for precision and accuracy was 5% or less from 50–500 ng/ml. The method is applicable to the assay of ceftazidime, cephaloridine, cefpirome and BMY-28142 with minor modification of the mobile phase and the detection wavelength.     

Simultaneous High-Performance Liquid Chromatographic and First-Derivative Spectrophotometric Determination of Amitriptyline Hydrochloride and Chlordiazepoxide In Capsules

Abstract

Rapid, precise, accurate and specific high-performance liquid chromatographic and first-derivative spectrophotometric procedures were described for the simultaneous analysis of amitriptyline and chlordiaze-poxide in two-component capsule formulations.

A reversed phase Micropack MCH-5 (CI8) column with a mobile phase composed of acetonitrile/water in a ratio (50:50) at pH3 and containing 0.01 M sodium-n-octane sulfonate separated amitriptyline, chlordiazepoxide and diazepam (internal standard). the drugs were detected at 230 nm at ambient temperature. the trough amplitudes in the first derivative spectrophotometric spectra at 245 nm and 282 nm were selected to determine amitriptyline and chlordiazepoxide.

Commercial capsules and laboratory-prepared mixtures containing both drugs in different proportions were assayed using the developed methods. the results were of comparable accuracy as indicated by the statistical analysis of data using t-test and F-test.     

Simultaneous Analysis Of Estradiol Dienanthate,Estradiol 3-Benzoate And Testosterone Enanthate Benzilic Acid Hydrazone In Oily Formulations Bygradient-Hplc

Abstract

A procedure is described for the analysis of estradiol-3-benzoate, testosterone enanthate benzylic acid hydrazone and estradiol dienanthate in oily solution. The multi-step gradient reversed phase ion-pairing HPLC method uses 1-pentane sulfonic acid sodium salt (0.0025 M in 0.1% acetic acid methanolic solution): acetonitrile and water (55 : 30 to 45 : 15 to 0) mobile phase gradient and a 250 × 4.6 mm, 5 micron octadecyl silane column, with 1,2,4,5-tetrachlorobenzene as internal standard. The time required for chromatography is 31 minutes. The method gives relative standard deviations (RSD) of .94% or better for the assay of active ingredients in commercial formulations.     

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.     

High-Performance Liquid Chromatographic Determination of Atenolol in Tablets

Abstract

A reversed phase high-performance liquid chromatographic method was developed for the determination of atenolol in four oral 100 mg atenolol preparations.

An aliquot of the sample is dissolved in a mobile phase consisting of 0.0612 M potassium hydrogen phosphate - isopropanol-tetrahydrofuran (84:10:6) v/v). The pH was adjusted to 6.7 with phosphate buffer. Nicotinamide was used as internal standard and chromatographed on a Pinkerton column ISRP (GFF-S5–80) 5 μm, 150 × 4.6 mm i.d. The applied column is convenient for the assay at least 90 samples of atenolol without degrading column performance. The detection was performed at 272 nm. The retention time for atenolol was 5.07 min.

The proposed HPLC method was found to be suitable for the rapid and precise routine analysis of atenolol in tablets.     

Simultaneous spectrophotometric and liquid chromatographic determination of dextromethorphan hydrobromide,phenylephrine hydrochloride,and carbinoxamine maleate in pharmaceutical preparations

Simultaneous determination of dextromethorphan hydrobromide (DEX), phenylephrine hydrochloride (PHEN), and carbinoxamine maleate (CAR) in pharmaceutical preparations was performed by using liquid chromatograpy (LC) and spectrophotometry. In LC, the separation was achieved on a C18 column and the optimal mobile phase for satisfactory separation in a gradient elution program was found to be acetonitrile-sodium perchlorate solution (5: 95, v/v) initially, then a linear gradient up to 60% acetonitrile in 8 min. In spectrophotometric method, a chemometric technique, principal component regression (PCR), was used. In the method, the absorbance data matrix corresponding to the concentration data matrix was obtained by the measurement of absorbances in their zero order spectra by Δλ = 1 nm in the 210–300 nm range. Then, the calibration was obtained by using this data matrix for the prediction of unknown concentrations of DEX, PHEN, and CAR in their ternary mixture. The methods proposed were validated and successfully applied to a pharmaceutical preparation, capsule, and the results were compared.     

Development and Validation of High Performance Liquid Chromatographic and UV-Derivative Spectrophotometric Methods for the Determination of Sotalol Hydrochloride in Tablets

Abstract

High performance liquid chromatographic (HPLC) and UV derivative spectrophotometric (UVDS) methods were developed and validated for the quantitative determination of sotalol hydrochloride in tablets. The HPLC method was performed on a C18 column with fluorescence detection. The excitation and emission wavelengths were 235 and 310 nm, respectively. The mobile phase was composed of acetonitrile-water containing 0.1% trietylamine (7:93 v/v) and pH adjusted to 4.6 with formic acid. The UVDS method was performed taking a signal at 239.1 nm in the first derivative. The correlation coefficients (r) obtained were 0.9998 and 0.9997 for HPLC and UVDS methods, respectively. The proposed methods are simple and adaptable to routine analysis.     

Quantitative Determination of Nadolol in Tablets by High‐Performance Liquid Chromatography and UV‐Derivative Spectrophotometry

Abstract

High‐performance liquid chromatographic (HPLC) and UV derivative spectrophotometric (UVDS) methods were developed and validated for the quantitative determination of nadolol in tablets. The HPLC method was performed on a C18 column with fluorescence detection. The excitation and emission wavelengths were 230 and 300 nm, respectively. A mobile phase composed by acetonitrile‐water containing 0.1% triethylamine (15∶85 v/v) and pH adjusted to 4.6 with formic acid was used. The UVDS method was performed taken a signal at 279.5 nm. The correlation coefficient (r) obtained for both methods was 0.9999. The proposed methods are simple, precise, accurate, and can be used in routine analysis.     

High-Performance Liquid Chromatography of MDL-035 in the Plasma of Rats,Dogs and Humans

Abstract

A sensitive and reproducible high performance liquid chromatographic method was set up for the assay of MDL-035, a new non-steroidal, nonacidic analgesic antiinflammatory agent, in the plasma of rats, dogs and humans. Plasma samples (0.5ml) containing flurazepam as the internal standard, were diluted and extracted with ethyl ether. After centrifugation, the organic phase was taken to dryness, the residue was redissolved and injected into an RP-2 column. The elution was made in isocratic conditions using a CH.CN/phosphate buffer solution as mobile phase. The UV detection was made at 320 nm. The method was validated for the concentration range from 0.05 to 10 ug/ml, and applied to pharmacokinetic studies. A typical plasma concentration-time profile in the rat after an oral administration is here presented.     

A Reverse Phase HPLC Assay for the Determination of Calcium Pantothenate Utilizing Column Switching

Abstract

A reverse phase HPLC assay utilizing column switching has been developed and validated for the determination of calcium pantothenate (CP) in several multivitamin tablet formulations. The reverse phase system utilizes a DuPont Zorbax C-8 analytical column, an automatically switched and backflushed Brownlee RP-18 guard column for the elimination of a highly retained excipient peak, 88:12 0.25M phosphate buffer:MeOH mobile phase, and 214 nm detection. Sample preparation and the switched column chromatography cycle each require approximately 15 minutes. A spiked recovery study showed linearity over the 50–150% of theory concentration range. Average recovery was 99.7%. Assay precision studies yielded sample RSD's ranging from 0.8 to 2.3%. Results obtained by this method are comparable to those obtained by the USP method.     

Assay of Arginine-Esterase Activities by Reversed Phase High Performance Liquid Chromatography

Abstract

Application of a high performance liquid chromato-graphic technique to assay of arginine-esterase activities is presented. Enzyme reaction was carried out with benzoyl-L-arginine ethylester as a substrate and analysis was performed on a reversed phase chromato-graphic system using a μ Bondapak C₁₈ or a Radial-PAK A column and buffered aqueous methanol as the mobile phase. The enzyme activities were determined by the peak height of cleaved product (benzoyl-L-arginine). The minimum detection limit for benzoyl-L-arginine was 0.02 nM on each column. The generality of this method was demonstrated by its application to determination of plasmin activity, and so it might be suitable for both kinetic studies and routine assays of plasmin-like es-terases.     

Determination of Bendroflumethiazide in Plasma by High Performance Liquid Chromatography and Fluorescence Detection

Abstract

An accurate, precise, and specific assay is described for the determination of bendroflumethiazide (BFTZ) in plasma. The procedure employs a C18 column, a mobile phase consisting of 35% acetonitrile in 0.015M phosphoric acid, and a fluorescence detector with a 254nm excitation filter and a 400nm emission filter. Furosemide is used as the internal standard. Using lml of plasma, this method can detect 10ng/ml of BFTZ.     

Simultaneous Determination of Senecionine,Senlciphylline, and Senecionine N-Oxide in Gynura segetum by RP-HPLC

Abstract

A rapid reversed-phase high-performance liquid chromatographic (RP-HPLC) method was established for simultaneous determination of senecionine, senlciphylline, and senecionine N-oxide in a famous traditional Chinese medicine, Gynura segetum, which has been commonly used for hemostasis. The HPLC assay was performed on a Kromasil KR100-5 C₁₈ column (25 cm × 4.6 mm, 5 µm) with mobile phase composed of acetonitrile and 0.2% phosphoric acid–triethylamine within 40 min. The detection wavelength was 220 nm. All the compounds showed good linearity (r² > 0.9997). The method was reproducible with intra- and interday variation less than 2.82%. The recovery of the assay was in the range of 96.55–103.88%. The method was successfully applied to the quantification of three constituents in 15 Gynura segetum samples collected from different metropolis. The results indicated that the developed assay could be considered as a suitable quality-control method for Gynura segetum.     

Comparative Spectrophotometric,Spectrofluorometric, and High‐performance Liquid Chromatographic Study for the Quantitative Determination of the Binary Mixture Felodipine and Ramipril in Pharmaceutical Formulations

Abstract

Two‐component mixtures of felodipine (FLD) and ramipril (RMP) were assayed by derivative UV spectrophotometry, spectrofluorometry, and high performance liquid chromatography (HPLC). The spectrophotometric methods included a zero‐crossing first‐ and second‐order derivative procedure and a derivative compensation technique for the determination of binary mixtures with overlapping spectra. The spectrofluorometric method was based on first‐ and second‐order derivatives of the emission spectra (zero‐crossing point). Results from these methods were compared with those obtained by an exclusively developed isocratic reversed phase HPLC method. A reversed‐phase Adsorbosil DS analytical column, with methanol‐acetonitrile‐water (50∶30∶20, v/v) mobile phase at a flow rate of 1.5 ml/min, was used with a UV detector. The temperature was set at 25±0.2°C. Results obtained by the spectrophotometric and spectrofluorometric methods were comparable to those obtained by the HPLC method, as far as analysis of variance (ANOVA) test results were concerned. It is concluded that the developed methods are equally accurate, sensitive, and precise; with direct and simple application to pharmaceutical formulations of felodipine and ramipril combination, without interference from common pharmaceutical adjuvants.     

A Stability Indicating HPLC Assay for Prednisolone Sodium Phosphate in Implantable Infusion Pumps

Abstract

A stability indicting assay for prednisolone sodium phosphate (PSP) in solutions for implantable infusion pumps was developed. PSP and its major breakdown product, prednisolone, were separated from formulation excipients by reverse phase chromatography on a phenyl-bonded phase column using an acetonitrile-phosphate buffer mobile phase. Detection was by ultraviolet absorbance at 243 mm. Recovery from a synthetic formulation was 101.0 ± 0.4% (n=6). The method was used to monitor the stability of PSP solutions in implantable infusion pumps maintained at 37°C over a 21 day period.     

High-Performance Liquid Chromatography of Domoic Acid,a Marine Neurotoxin,with Application to Shellfish and Plankton

Abstract

A recent outbreak of poisoning resulting from the consumption of cultured blue mussels (Mytilus edulis L.) from a localized area in Eastern Canada has been attributed to the presence of domoic acid (1), a relatively rare neurotoxic amino acid, previously found only in some algae of the family Rhodomelaceae. Studies on aqueous extracts of shellfish tissue indicated that the toxin and several of its isomers could be separated (and isolated in sufficient amounts for subsequent structural identification) by reversed-phase high-performance liquid chromatography (HPLC) with ultraviolet (UV) diode array detection (DAD). Aqueous acetonitrile containing 0.1% v/v trifluoroacetic acid was used as mobile phase. As the retention time and characteristic UV absorption spectrum of 1 (λ_max = 242 nm) permit unequivocal identification, the HPLC-DAD procedure was refined with a microbore column to provide a rapid (5 min), sensitive (0.3 ng detection limit) and reproducible assay method for the determination of 1 in shellfish tissue. Extraction was accomplished by boiling homogenized shellfish tissue for 5 min with distilled water. Extracts were taken through an octadecylsilica solid phase extraction clean-up prior to HPLC. This method has been applied to a variety of shellfish and phytoplankton samples.

BRIEF

Reversed-phase HPLC with ultraviolet diode array detection was used to analyze shellfish tissue and phytoplankton extracts for domoic acid. A rapid (5 min) and sensitive (0.3 ng detection limit) assay is presented.     

A Rapid and Inexpensive Thin Layer Chromatographic Method for Quantitative Analysis of Bleomycin Complex

Abstract

A densitometric and a spectrophotometric method for rapid but accurate determination of different components of bleomycin injections has been described. The bleomycin components were separated by reversed phase thin layer chromatography on silanized silicagel plates using a mixture of aqueous ammonium nitrate (2.5%) : methanol :: 7 : 3 (v/v) as mobile phase. Assay was done at the absorption maxima of the components (291 nm) by in situ densitometry or by spectroscopy after extracting the drugs from the adsorbent with the mobile phase. Results obtained by both the methods agreed well with each other and with those obtained by an official HPLC method. The densitometric method described was highly suitable for routine quality control of bleomycines as a large number of samples could be analysed within a short time (68 samples/analyst/day).