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PubMed1978

Determination of drugs in plasma by high-performance thin-layer chromatography.

High-performance thin-layer chromatography was used to determine chlorpromazine, amitriptyline, nortriptyline, imipramine, desipramine, phenobarbital, and phenytoin in plasma, to demonstrate the utility of this technique for routine analysis. We quantitated the separated components by use of ultraviolet reflectance spectrometry with detection limits as low as 1 microgram/liter. Regressions of psychoactive agents extracted from plasma were linear over the range of 0 to 300 microgram/liter. The anti-convulsant drugs, phenobarbital and phenytoin, were determined over a range of 0 to 50 mg/liter. Analyses were rapid, reproducible, and well-suited to large-scale programs. Separated components also can be identified in situ by ultraviolet spectrophotometry.

Amitriptyline↗
PubMed1982

Liquid chromatographic identification of cis- and trans-cinnamoylcocaine in illicit cocaine.

A liquid chromatographic procedure is described for the analysis of illicit cocaine samples. The isomeric cis- and trans-cinnamoylcocaines are separated from cocaine, benzoylecgonine, and benzoic acid in a reverse phase isocratic system with dual wavelength detection at 254 and 280 nm. Specific identification of cocaine and the cinnamoylcocaines is accomplished by ultraviolet spectrophotometry and mass spectrometry of the chromatographic effluent.

Chromatography, High Pressure Liquid↗
PubMed1981

Stability of procaine hydrochloride in a buffered cardioplegia formulation.

The stability of procaine hydrochloride in a buffered cardioplegia solution was studied. The formulation of Ringer's injection with added increments of potassium and magnesium plus procaine hydrochloride was buffered to a pH of 7.3-7.6 with tromethamine. Procaine hydrochloride content was measured in triplicate by ultraviolet spectrophotometry at set time intervals and at temperatures of 22, 40, and 61 degrees C. The time required for procaine to degrade to the lower shelf-life limit of 90% of its initial concentration was extrapolated to be approximately two days at room temperature and 11 days under refrigeration. It is recommended that the basic buffered cardioplegia solvent be manufactured separately, and the procaine hydrochloride be added at the time of dispensing to minimize its loss of potency.

Drug Stability↗
PubMed1980

Isolation and identification of biologically active contaminants from soft contact lenses. I. Nicotine deposits on worn lenses.

A method for elution of contaminants deposited onto soft contact lenses during wear utilizing a nondestructive cleaning procedure is presented. Twenty-five soft contact lenses supplied by American Optical Corp. were pooled and subjected to 20% H2O2 (hydrogen peroxide). The resulting wash was extracted with organic solvents, hydrolyzed, and re-extracted. The organic-soluble fraction was further divided into strong acids, intermediate acids, neutrals, and bases. Sequential separation, isolation, characterization, and confirmation of constituents were achieved with thin-layer chromatography, ultraviolet spectrophotometry, and microcrystallography. Photomicrographs before and after cleaning were obtained to assess the optical quality of the lenses. Initial emphasis has been to characterize naturally occurring, biologically active constituents and common environmental toxins of molecular weight 150 to 500. We find that nicotine, a common environmental pollutant and a significant component of the blood of people who smoke regularly, is one of the contaminants present on a worn soft contact lens.

Chemistry, Organic↗
PubMed1977

Measurement of plasma contrast levels during excretory urography.

Ultraviolet spectrophotometry permits easy measurement of plasma levels of intravenously injected contrast media. The initial results are described from the determination of plasma methylglucamine iothalamate (Conray 60) levels during routine excretory urography in 10 normal patients. This simple procedure has many potential applications in the investigation of contrast media physiology.

Humans↗
PubMed1996

Evidence for presence of a reduced form of digoxin-like immunoreactive factor (dihydro-DLIF) in mammalian tissues.

Digoxin-like immunoreactive factor (DLIF) from adrenal glands is an endogenous ligand structurally related to the plant-derived cardiac glycoside digoxin. Cardiac glycosides regulate the activity of the sodium pump and thus play key roles in disease processes involving regulation of ion transport. We now report the discovery of an endogenous dihydro-DLIF analogous to dihydrodigoxin. We used HPLC, ultraviolet spectrophotometry, and cross-reactivity with two antibodies, one specific for digoxin and one for dihydrodigoxin, to support the hypothesis that dihydro-DLIF contains a chemically reduced lactone ring. The spectral absorbance maximum for dihydro-DLIF is at 196 nm, identical to dihydrodigoxin. DLIF and dihydro-DLIF are 975- and 2588-fold less immunoreactive than digoxin and dihydrodigoxin for their respective antibodies. The molar ratio of dihydro-DLIF to DLIF is approximately 5.3 in bovine adrenocortical tissue and approximately 0.38 in human serum. Dihydrodigoxin (reduced lactone ring) added to microsomes isolated from bovine adrenal cortex produced a 4.5-fold increase in digoxin-like immunoreactivity (oxidized lactone ring) after 3 h of incubation. The biotransformation is likely mediated by a cytochrome P-450 NADPH-dependent process. Our findings demonstrate the presence of a dihydro-DLIF in mammals and suggest a metabolic route for synthesis of endogenous DLIF in mammalian tissue.

Adrenal Cortex↗
PubMed2002

Synthesis of targeted drug delivery system for fluorouracil using sulfadiazine as the carrier.

OBJECTIVE: To synthesize a targeted drug delivery system for 5-fluorouracil (5Fu) using sulfadiazine (SF) as a carrier with reduced side-effects and strong antitumor activity. METHODS: SF-poly (ethylene glycol) (PEG) conjugate was initially synthesized. 5Fu was subjected to reaction with trichloromethyl chloroformate to prepare chloroformyl 5Fu, which was linked to a spacer hydroxyl group of PEG that served as a macromolecular linking arm between SF and 5Fu. The content of 5Fu in the conjugate was determined by ultraviolet spectrophotometry. Spectrum of ultraviolet and infrared along with differential scanning calorimetry were employed to identify the structure of the conjugate of SFPEG-end capped 5Fu. RESULTS: The drug loading content of the conjugate was 3.2 %, and structural analysis confirmed the linkage between 5Fu and SF via PEG. CONCLUSION: Targeted drug delivery system for 5Fu using SF as a carrier has been successfully synthesized by this means.

Antimetabolites, Antineoplastic↗
PubMed2005

Derivative ultraviolet spectrophotometric determination of dexchlorpheniramine maleate in tablets in presence of coloring agents.

Formulation excipients can frequently affect the drug analysis in pharmaceuticals yielding background interference by ultraviolet spectrophotometry. Sample separation procedures to diminish such interferences are usually recommended as sample pre-treatment, however it can be difficult to eliminate them and they can still persist. In addition, these procedures can be time consuming and laborious to perform. Excipients, like dyeing agents can also be present in a formulation and yield color to drug solution. This work reports the successful development of a derivative ultraviolet spectrophotometry for dexchlorpheniramine maleate (DPM) determination in solid dosage forms, in spite of the color imparted to tablets solution. Standard curves obtained by second order derivative ultraviolet spectrophotometry showed linearity with a correlation coefficient of 0.9999 in the concentration range of 9.75-32.5 microg ml(-1) DPM in 0.1 mol l(-1) sulfuric acid, using zero-peak (ZP) and peak-peak (PP) methods. The average relative standard deviation range was between 0.26% and 1.08% and 0.18% and 0.63% for ZP and PP methods, respectively. Application of the method in tablet samples resulted in coefficients of variation in the range of 0.83-1.40%, and 0.63-0.83% for ZP and PP methods, respectively. Recovery test percentage values obtained were between 96.95% and 105.61% for the tested tablet samples.

Calibration↗
PubMed1993

Improved detection limits for screening of diuretics by coupled liquid chromatography and ultraviolet-visible spectrophotometry.

Experimental conditions have been studied in order to improve the sensitivity for the analysis of diuretics and probenecid in urine samples by high-performance liquid chromatography with ultraviolet detection. Sample clean-up and chromatographic parameters have been optimized to obtain a suitable sensitivity for the detection or quantification of each diuretic using an HP-Hypersil ODS-C18 column (5 microns, 250 mm x 4 mm I.D.), taking into account the pharmacological properties of each compound. The reliability of this method was tested by analysing urine samples after a minimum single-dose administration of chlorthalidone and probenecid.

Chlorthalidone↗
PubMed1993

Identification of rigid gas permeable contact lens materials by means of ultraviolet-visible spectrophotometry.

Identification of the material used in an unknown rigid gas permeable (RGP) contact lens is not easily achieved by either manufacturer or contact lens practitioner. It is proposed that the spectral transmittance characteristics in the ultraviolet and visible regions can characterize a material sufficiently to identify it. The characteristics of some materials are discussed and a short double blind trial of the identification system reported. Ultraviolet-visible spectrophotometers are widely available and can be relatively inexpensive. The method is proposed as being a practical reality.

Contact Lenses↗
PubMedDate not supplied

[Validation of triiodothyronine sodium analysis method].

OBJECTIVE: To validate the ultraviolet spectrophotometry analytical method for triiodothyronine sodium in order to use this method in the quality control process of a diluted powder of said active principle for the manufacturing of 25 mcg capsules. MATERIAL AND METHODS: An ultraviolet spectrophotometry analysis is performed on triiodothyronine sodium to obtain its spectrum. Subsequently, a mother solution of triiodothyronine sodium is made, from which 5 different-concentration dilutions are prepared in order to obtain a calibration line allowing the study of the method's linearity. Then 3 of these 5 dilutions are selected for repeatability and reproducibility studies. Two pattern solutions with differing concentrations are prepared for the accuracy study. Three different-concentration dilutions are prepared from each of them. The absorbencies of controls for both pattern solutions are measured to compare results obtained. RESULTS: A scan is performed between 350 and 200 nm, and an experimental peak of 319 nm is obtained. The method proves linear for the considered range of concentrations (r(2) = 0.9985). Variation coefficients are around 2%, thus indicating good repeatability and reproducibility. The mean percentage of recovery in known-concentration samples does not significantly differ from the theoretical 100%. CONCLUSION: The studied analytical method is adequately reliable to result in a foreseen result within defined intervals.

Capsules↗
PubMed2003

[Spectral analysis of maorenshen (Actinidia valvata) and its confusable materials].

This article reports the spectral analysis of Maorenshen (Actinidia valvata) and its confusable materials Actinidia chinennsis and Actinidia polygama by fluorescence test, ultraviolet spectrophotometry and fluorescence spectrophotometry. Strong green or blue fluorescence was observed at UV 254 nm in aqueous solutions of Actinidia chinesis and Actinidia polygama, and was barely seen in that of Maorenshen. There were also obvious differences among the ultraviolet spectra and fluorescence spectra of the extracted solutions of the three materials. No obvious absorption band was observed in the UV spectra of ethanol-extracted solution of Maorenshen, an absorption band at 280 nm was observed in the UV spectra of Actinidia chinensis and Actinidia polygama in ethanol extract-solutions. There were also different wavelength and strength in fluorescence spectra among extracted solutions of Maorenshen, Actinidia chinensis and Actinidia polygama. Therefore, it is feasible to identify Maorenshen (Actinidia valvata) and its confusable materials by ultraviolet spectrophotometry and fluorescence spectrophotometry.

Actinidia↗
PubMed2002

[Determination of papaverine hydrochloride in skin and blood and the drug contents in pig skin].

OBJECTIVE: To explore the application of ultraviolet spectrophotometer in determining papaverine hydrochloride content in blood and skin and to determine the intradermal content after local external application of papaverine hydrochloride. METHODS: Phosphate buffer solution (pH = 10, ionic strength = 0.4) was added into the blood or ground skin tissue containing papaverine hydrochloride, and papaverine hydrochloride was extracted with chloroform-hexane mixture (ratio:2:3). After oscillation and centrifugation, partial organic phase was retrieved and dried in 60 degrees C water bath. The dried product was dissolved in 1 mol/L HCl and then underwent filtration through 0.2 micron membrane. The ultraviolet apectrophotometry was applied to determine the content of papaverine hydrochloride in the filtrate. 2% papaverine hydrochloride cream was applied on pig's skin and skin specimen was retrieved at given time to determine the papaverine hydrochloride content in skin tissue with ultraviolet spectrophotometry. RESULTS: The absorbance spectrum of the extract was typical of that of papaverine hydrochloride, with no miscellaneous peak. The extractive rate of papaverine hydrochloride in blood of was more than 92% and that in skin tissue more than 87%. Eight hours after external application of 2% papaverine hydrochloride cream on pig skin, the content of papaverine hydrochloride in skin tissue was more than 90 micrograms/g, significantly higher than the effective concentration of papaverine hydrochloride. CONCLUSIONS: Ultraviolet spectrophotometry is a simple, economical and reliable method for the determination of papaverine hydrochloride content in blood and skin tissue, with good reproducibility and sensibility. External application of papaverine hydrocholine cream can provide efficient permeation and drug concentration in the skin.

Animals↗
PubMed2002

Second derivative spectrophotometric determination of trimethoprime and sulfamethoxazole in the presence of hydroxypropyl-beta-cyclodextrin (HP-beta-CD).

An easy and rapid second-derivative spectrophotometric method for the simultaneous analysis of trimethoprime (TMP) and sulfamethoxazole (SM) is described. These drugs have been used as antibacterial against a wide spectrum of organisms and combinations of these drugs are commonly used for the treatment of a variety of infections. The most advantageous approach of this method is the use of HP-beta-CD, which allows to improve the performance of the second-derivative ultraviolet spectrophotometry. For both compounds, a shift of the absorption bands and variations of their intensity were observed. The calibration graphs were linear in the concentration range of TMP (1.92-19.2 microg ml(-1)) and SM (1.60-16.5 microg ml(-1)), the correlation coefficient for the calibration graphs was better than 0.9994 and the precision was satisfactory (CV%< 4.96) in HP-beta-CD solutions. The proposed method was successfully applied to the assay of commercial tablets. The results were compared to those obtained by second-derivative ultraviolet spectrophotometry in the absence of HP-beta-CD. Thereby, the details of the statistical treatment of the analytical data are also presented.

2-Hydroxypropyl-beta-cyclodextrin↗