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Biomedical subjects

J H Perrin

Publications and source records attributed to J H Perrin.

At least 19 recordsLinked to original sources
PubMed1997

A quantitative circular dichroic investigation of the binding of the enantiomers of ibuprofen and naproxen to human serum albumin.

The binding constants for racemic, R and S naproxen and ibuprofen to human serum albumin have been determined by a circular dichroic technique. The ibuprofens and naproxens show no measurable extrinsic optical activity on interaction with the protein, and so the extrinsic Cotton effect shown following the diazepam-albumin interaction is used as a probe. The presence of the drugs reduce the amount of diazepam bound as shown by the interaction is used as a probe. The presence of the drugs reduce the amount of diazepam bound as shown by the reduced size of the induced ellipticity. The calculated primary binding constants show that the S form of both drugs bind to the albumin more tightly than the R form and that the racemic forms bind less tightly than either enantiomer.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

The effect of octanoic acid on the binding of the enantiomers of ibuprofen and naproxen to human serum albumin: a chromatographic implication.

PURPOSE: The heats of reaction between the enantiomers and racemates of ibuprofen and naproxen and human serum albumin (HSA) are to be measured with and without the addition of octanoic acid. The effects of octanoic acid on the free energies of interaction between the drugs and HSA is to be determined and compared to that estimated from theoretical equations. METHODS: The heats of reaction have been measured directly by flow microcalorimetry. RESULTS: The data showed that octanoic acid lowered the 1:1 binding constants for all the drug-HSA interactions investigated. The effect of octanoic acid was greater on the R than on the S forms of the drugs as shown by the differences in free energies of interaction in the presence and absence of octanoic acid. CONCLUSIONS: The increased free energy differences for the binding of the enantiomers of both drugs to HSA in the presence of octanoic acid is closer to the value deemed to be necessary for the separation of enantiomers by Davenkov, and shows the importance of the addition of octanoic acid to the mobile phase in the separation of these enantiomers on immobilized albumin columns.

Calorimetry↗
PubMed1994

Effects of drug-binding on the thermal denaturation of human serum albumin.

Asymmetric thermograms of defatted albumin, alone and in the presence of two model drugs, have been obtained in phosphate buffers at three pH values. The albumin is less thermally stable in the N form, but is protected by both drugs. The nonsteroidal antiinflammatory benoxaprofen offers more protection than warfarin against thermal denaturation.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1994

Pharmacokinetic evaluation of two ibuprofen-codeine combinations.

The pharmacokinetics of ibuprofen and codeine were compared when given alone or in combination. Six treatments (ibuprofen 400 mg, codeine 60 mg, ibuprofen 400 mg and codeine 30 mg in two separate tablets, ibuprofen 400 mg and codeine 30 mg in one combination tablet, ibuprofen 400 mg and codeine 60 mg in two separate tablets, and ibuprofen 400 mg and codeine 60 mg in one combination tablet) were evaluated. Twenty-four healthy subjects were enrolled in the randomized block design study. Ibuprofen and codeine plasma concentrations were measured by reversed-phase liquid chromatography with UV and fluorescence detection. Pharmacokinetic parameters were estimated by non-compartmental data analysis techniques. Ibuprofen and codeine pharmacokinetic parameters obtained in this study were in agreement with previously published values. In addition, no pharmacokinetic interaction could be detected between codeine and ibuprofen when given alone or in combination. Furthermore, the similar half-life of both drugs (2-2.5 h) is advantageous for a fixed drug combination. The results suggest that ibuprofen and codeine can be given safely in a single oral dosage form.

Administration, Oral↗
PubMed1991

Effects of tricyclic drug on induced circular dichroism spectra of dicumarol bound to alpha 1-acid glycoprotein.

Effects of both tricyclic and non-tricyclic drugs on the extrinsic Cotton effects of dicumarol bound to human alpha 1-acid glycoprotein (AGP) have been investigated. Basic tricyclic drugs caused the reversal of the signs of the induced Cotton effects of the circular dichroism (CD) spectra of the dicumarol-AGP system while the basic drugs not possessing tricyclic rings and acidic drugs decreased the observed ellipticities without changing the signs of its CD spectra. There was no reversal of the CD signs of the drugs not containing two hydroxycoumarin rings bound to AGP by basic tricyclic drugs. Raising of pH and temperature, and the addition of guanidine hydrochloride decreased the observed ellipticities of the CD spectra of the dicumarol-AGP system without showing any change in the signs of the Cotton effects. The mutual displacement data showed that protriptyline increased its own binding and that of dicumarol with AGP. The results of CD titration and equilibrium dialysis experiments suggest that dicumarol-AGP and dicumarol-AGP-protriptyline form a 1:1 binary complex and a 1:1:1 ternary complex, respectively.

Antidepressive Agents, Tricyclic↗
PubMed1991

Penicillin-enhanced chemiluminescence of the luminol-H2O2-Co2+ system.

The luminol-H2O2-Co2+ system has been widely used in chemical and biological analysis. We report here an investigation of the observation that penicillins have the ability to prolong and enhance the intensity of chemiluminescence from luminol. The basis of this phenomenon appears, as revealed by difference spectroscopy, to be the formation of a complex between the beta-lactam and the superoxide ion. The latter is the oxidizing species responsible for the oxidation of luminol in alkaline solution and has a mean lifetime, in solution, of milliseconds. The stabilization of the superoxide ion by penicillin complexation extends the effective lifetime of the superoxide ion by a few orders of magnitude and thereby allows for more efficient oxidation of the beta-lactam. Several penicillins were determined by their enhancement of luminol chemiluminescence. A detection limit of 100 ng mL was obtained for penicillin G with a less-than-ideal detection system.

Catalysis↗
PubMed1989

Diode array spectroscopy in pharmaceutical analysis: determination of acetaminophen/codeine phosphate tablets.

The use of diode array spectrophotometry for the analysis of tablets containing acetaminophen and codeine has been investigated. The technique was found to be applicable to the analysis of tablets which nominally contain 300 mg acetaminophen and 15, 30 or 60 mg codeine phosphate (Tylenol Nos 2-4, respectively). The concentration of codeine in extracts of Tylenol No. 1, which contains 7.5 mg codeine phosphate, was found to be too low for precise determination. First-derivative spectroscopy is required for the analysis of Tylenol Nos 2 and 3. Tylenol No. 4 can be determined using either the zero or the first-derivative spectra; however, the former was found to give consistently lower values for each component. The influence of derivative order and analytical wavelength range on the precision was investigated. The accuracy of the procedure was assessed by comparing the results from spectroscopy with those from liquid chromatography. Finally, some general conclusions on the applicability of diode array spectroscopy for the multicomponent analysis of pharmaceuticals are presented.

Acetaminophen↗
PubMed1989

Effect of pH and small inorganic ions on binding of sulfadimethoxine and sulfaphenazole to human serum albumin measured by circular dichroism.

The binding of sulfadimethoxine and sulfaphenazole to human serum albumin (HSA) has been shown by circular dichroism measurements to be dependent on the N-B transition. The secondary drug binding sites were found to be optically active in the B conformation form in HSA but optically inactive in the N form. Moreover, the drug-HSA interaction in Tris-HCl buffer seems to be more sensitive to the conformational change in HSA, compared with that in the phosphate buffer.

Circular Dichroism↗
PubMed1988

Analysis of some dosage forms containing pyridine derivatives using a cyclodextrin bonded stationary phase in HPLC.

The high performance liquid chromatography of some pyridine derivatives using a silica column to which beta-cyclodextrin has been bonded, has been investigated. In spite of the low affinity constants of the drugs for cyclodextrin (of the order of 10(2) M(-1)) good separations can be achieved using a mobile phase of methanol and pH 7.0 phosphate. Good analysis of some dosage forms are achieved, including one on a tablet containing pheniramine maleate, pyrilamine maleate and phenylpropanolamine hydrochloride. Extractions and chromatography are quick and simple.

Journal Article↗