Comparison of the pharmacokinetics of miconazole after administration via a bioadhesive slow release tablet and an oral gel to healthy male and female subjects.

AIMS: The aim of this study was to compare salivary miconazole pharmacokinetics following once daily application of bioadhesive tablets (50 or 100 mg), vs the current treatment with a gel (3 times a day, 375 mg day(-1)). METHODS: A three way cross over study was carried out in 18 healthy subjects (nine males, nine females) with a 1 week washout period between each treatment. Plasma and salivary pharmacokinetics of miconazole were assessed over a 24-h period. RESULTS: In all subjects the tablets gave higher and more prolonged salivary miconazole concentrations than the gel. Thus salivary miconazole AUC(0,24 h) was 37.2 times greater for the 100 mg tablet (90% confidence interval [CI] 22.9, 60.5) and 18.9 times greater for the 50 mg tablet (CI 11.7, 30.6) compared with the gel. Similarly, Cmax was 17.2 times greater (CI 11.8, 25.2) and 7.8 times greater (CI 5.3, 11.4) for the 100 mg tablet and 50 mg tablet, respectively. Comparison of the 100 mg and 50 mg tablets gave ratios of 2.2 and 2.0 for Cmax and AUC(0,24 h), respectively (CI 1.5, 3.2 and 1.2, 3.2). The mean time that salivary miconazole concentrations were above 0.4 micro g ml(-1) (the concentration reached 3 h after application of the oral gel according to published data) or above 1.0 microg ml(-1) (the MIC of some Candida species) was greater for both bioadhesive tablets than for the oral gel (10-14 h vs 1.5 h and 7 h vs 0.6 h). Only 19 plasma samples from eight subjects had concentrations of miconazole above 0.4 micro g ml(-1). Ten of these were taken from five subjects after administration of the gel and nine from three subjects after administration of the tablets. CONCLUSIONS: These data strongly support the further development of miconazole bioadhesive tablets as a sustained release formulation leading to improved antifungal exposure in the buccal cavity. A single daily application should improve compliance, whereas the low systemic absorption of miconazole will alleviate concerns regarding drug interactions and adverse effects.

High-performance liquid chromatographic determination of phenylephrine and tropicamide in human aqueous humor.

A high-performance liquid chromatographic method for the simultaneous determination of phenylephrine and tropicamide in human aqueous humor was developed. After centrifugation, an aliquot of the supernatant was injected onto the column and the eluent was monitored at 280 nm then 254 nm after 5 min. Separation was performed on a CN column with 0.01 M Pic B8 (octane sulfonic acid)-acetonitrile (65:35, v/v) as mobile phase. The standard curves were linear in the detection range. The precision of the method (expressed by relative standard deviation) and the accuracy (mean error in per cent) were <5% for both intra- and interassays.

Relationships of immunoglobulins E and G sensitization to respiratory function in dairy farmers.

An impairment of respiratory function has been demonstrated in dairy farmers. The objective of this study was to evaluate the relationship of allergy to respiratory function in dairy farmers in a longitudinal study conducted in the Doubs (France). A cohort of male dairy farmers constituted in 1990 was re-evalued in 1995. Subjects completed a medical and occupational questionnaire, and a spirometry test in both 1990 and 1995, in 1995 they were also subjected to immunological tests. Relationships between immunological variables and respiratory function were studied by a multiple linear regression model adjusted for age, smoking status, respiratory symptoms, altitude and occupational exposure. Amongst the 394 subjects of the initial cohort, 330 were included in the longitudinal study and 320 had immunological tests. Log immunoglobulin (Ig) E was negatively correlated with the 1995 respiratory function parameters (p<0.05 for forced expiratory volume in one second (FEV1) and FEV1/vital capacity (VC). Immunoglobulin (Ig) G response to Aspergillus fumigatus detected by enzyme-linked immunosorbent assay (ELISA) was negatively correlated to 1995 respiratory function parameters (VC: p<0.01; FEV1: p<0.001; FEV1/VC: p<0.01). There was a positive relationship between IgG antibodies against Aspergillus fumigatus and the mean annual decline in FEV1 (p<0.01) and FEV1/VC (p<0.01). To conclude, allergy may play a role in the impairment of respiratory function in dairy farmers of the Doubs and sensitization to Aspergillus fumigatus seems to constitute an independent risk factor for the development of airflow obstruction in this occupational setting.

Bioinversion of ibuprofen enantiomers after administration in dogs: estimation of a novel index.

This study compares the pharmacokinetics and bioinversion of two chemical forms of ibuprofen administered intravenously or orally. Dogs were given the free acid form of the S(+) isomer p.o. or i.v., or the racemate, as the free acid or sodium salt, p.o., in a cross-over design. The main kinetic parameters were calculated and formation and bioinversion curves plotted. The values of Cmax, Tmax and AUC were higher for the S(+) isomer. The percentage bioinversion averaged between 35-70% according to the form. This study proposes a new index for the calculation of bioinversion, independently of any i.v. administration, and confirms its self-limiting nature.

Average parameters in bioavailability studies: an application to slow-release amitriptyline formulation.

In order to assess the extent and the rate of absorption in bioavailability studies, area under the curve (AUC), experimental maximum concentration (Cmax) and experimental time to reach Cmax (Tmax), are used. But when slow-release formulations are considered, the drug concentration-time curves usually show multiple peaks, and it is difficult to compute a Cmax and Tmax value. In case a Cmax value is computed, important variability in this parameter results in high values in the residual variance of the ANOVA test. So in order to decrease the high variability, average parameters: average concentration (Cav), average maximum concentration (Cmax,av) and Cmax,av x 100/Cav (%Cmax,av), are proposed. These new parameters were applied in a bioavailability study of slow-release amitriptyline formulation.

Bioavailability of morphine after administration of a new bioadhesive buccal tablet.

A new bioadhesive buccal morphine tablet was developed for controlled release delivery of drug and improved bioavailability compared with oral controlled release tablet. In order to characterize the pharmacokinetic properties of this bioadhesive buccal formulation, a bioavailability study was performed in 12 healthy volunteers who received: a 30 mg oral controlled release tablet (A); a 20 mg aqueous solution retained in the mouth for 10 min (B); and the 60 mg bioadhesive buccal tablet placed between the lower gum and lip for 6 h (C). The mean amount of morphine absorbed from the solution was very low, only 2 mg of the 20 mg dose. After administration of forms A and C, plasma levels exhibit typical sustained release concentration-time curves. The mean amount of drug recovered from the residual bioadhesive buccal tablet after 6 h indicated that approximately 50% of the dose was released from the bioadhesive buccal tablet. The relative bioavailability of the buccal tablet (corrected for residual unabsorbed dose) compared with the controlled-release tablet was 98% based on the morphine AUC values. Good correlations between the AUC and the Cmax of the bioadhesive tablet for the drug and metabolite plotted versus the amount of morphine absorbed were found.

Insolubilization test of sodium chondroitin sulphate with a view to its use as colonic carrier of drugs.

Several studies have been devoted to cross-linked sodium chondroitin sulphate (SCS), in the context of numerous strategies attempting to target the colon for the absorption or the therapeutic action of a drug. SCS, a glycosaminoglycan presenting a specific degradation in the colon, is in fact soluble in water and its use as drug carrier at such a distance from the digestive tube necessitates its hydrophobisation. One method described in the literature consists in manufacturing a three-dimensional network by cross-linking with bifunctional compounds. However, all the structural characterisations carried out on the products resulting from the catalysed treatments of SCS with diaminoalkanes demonstrate that there are no cross-linking bridges between the polymer chains. Moreover, treated SCS-based tablets containing theophylline as model drug lead in vitro to dissolution profiles which are identical to those obtained with the non-treated SCS. We were therefore unable to find the announced results using the method described.

Simple and sensitive method for determination of metronidazole in human serum by high-performance liquid chromatography.

A simple and sensitive HPLC method for determination of metronidazole in human plasma has been developed. A step of freezing the protein precipitate allowed an efficient separation of aqueous and organic phases minimizing the noise level and improved therefore the limit of quantitation (10 ng ml(-1) using 1 ml of plasma sample). The separation of compounds was performed on a RP 18 column with acetonitrile-aqueous 0.01 M phosphate solution (15:85, v/v) as mobile phase. Detection was performed by UV absorbance at 318 nm. Metronidazole was well resolved from the plasma constituents and internal standard. An excellent linearity was observed between peak-height ratios plasma concentrations over a concentration range of 0.01 to 10 microg ml(-1). Within-day and between-day precision (expressed by relative standard deviation) and accuracy (mean error in per cent) did not exceed 4% between 1 and 10 microg ml(-1) and 8.3 and 7.2% respectively for the limit of quantitation. The method is suitable for bioavailability and pharmacokinetic studies in humans.

[About an original document published in Clermont in 1656 and entitled "Arrests du Roy, Arrests et Commissions portans establissement de l'Art des Apothicaires par toutes les Villes de France non jurée"]. / Sur un document original publié à Clermont en 1656, intitulé "Arrests du Roy, arrests et commissions portans establissement de l'art des apothicaires par toutes les villes de France non jurée".

This document is a part of the heritage of the public library of Clermont-Ferrand. It has been realized in 1656 by Germain Perdrix, official printer of the King, as a copy of the original printed in Paris. This document gathers some papers written during the lives of Kings Louis XIII and Louis XIV. The most important paper (published on January 20, 1637) specifies the conditions of admission to be Master in Apothecary as well as the rules of this profession.

[Transdermal therapeutic methods]. / Les thérapeutiques transdermiques.

Percutaneous absorption has now been largely demonstrated and is defined as the passage of a molecule applied to the skin from the external environment to the blood. This phenomenon takes place in two main steps: penetration and actual absorption. Percutaneous absorption avoids the first-pass effect to which orally and rectally administered molecules are submitted, although these molecules can be metabolized in the skin, but to a much lesser degree that by hepatic metabolism. Transdermal devices present many advantage compared to forms administered by other routes: improved patient compliance, easy self-administration, prolonged plasma plateau levels. However, it depends on the skin type and, in the case of allergic reactions, other classical forms designed for the cutaneous route, such as ointments or gels. There are two types of transdermal device: so-called matricial forms, which are semi-solid or solid preparations in which the active ingredient(s) can be dispersed or dissolved; reservoir systems, in which one of the walls is a membrane, placed directly on the skin. In the case of the nitroglycerin, plasma curves are essentially identical regardless of the type of device used. The active ingredients currently available on the market in the form of transdermal devices are scopolamine, nitroglycerin, 17-beta-oestradiol, nicotine, and, for the future, forms containing fentanyl, timolol, ephedrine ... are currently being developed.

[Problems raised by the reformulation of inhalations after the removing of propulsors "chlorofluorocarbons" (CFC)]. / Problèmes posés par la reformulation des inhalations après la suppression des propulseurs "les chlorofluorocarbones (CFC)".

The application of the Montreal convention which not only plans to remove CFCs from pressurized preparations but to stop also the production, will affect companies. However, for pharmaceutical use, antiasthmatic drugs are considered as essential and at the moment the use of CFCs is allowed. But if the production stops, a reformulation will be necessary. Three solutions are conceivable: The first one is to replace CFC 11, 12 and 114 with the old well known propellants as butane, isobutane, propane but they are not very compatible with pulmonary use. The second one is the use of new official substitutes as 134a (tetrafluorethane) or R227 (heptafluoropropane). The former is immediately available and can be used because its take of toxicity has been demonstrate by an international consortium, IPACT as well as the absence of action on ozone but a light "greenhouse effect" is expected. However, the simple substitution of CFCs for those two propellants is not easy due to their physical-chemical properties which are different from the old CFCs. This reformulation is so delicate that pharmaceutical companies have chosen a third solution: precompression pumps or clever devices which can deliver directly the pure drug in powder form. The other preparations to be used for dermatological or cosmetological uses have been reformulated since a long time with original and special presentation (bags in can or volatile solvents).

The formulation of drug for ocular administration.

The different barriers that slow the penetration of active ingredients administered by the ocular route are described, and some novel dosage forms designed for this route are discussed. Both precorneal and corneal factors considerably restrict ocular penetration. The low bioavailability of classical ophthalmic dosage forms can be improved by several approaches, particularly by increasing the time the active ingredients remain in contact with the eye tissues. The new dosage forms are reviewed according to their type and their drug release mechanisms. The characteristics, advantages, and limitations of each are outlined. The potential of these dosage forms can be expected to enhance development. They offer prolonged effectiveness, reproducibility, fewer unwanted side effects, and improved tolerance.

Influence of food on glycemia, insulin, C-peptide and glucagon levels in diabetic patients treated with antidiabetic metformin at steady-state.

Seventeen diabetic patients (5 males and 12 females) treated with long-term metformin therapy received their morning dose after an overnight fast or after one of four types of breakfast: low protein, low fat, low carbohydrate or standard. Mean (+/- SD) and median areas under the serum concentration curves (AUC), maximum concentrations (Cmax) and time to reach the maximum concentrations (tmax) were calculated for the major biological parameters (glycemia, C-peptide, insulin and glucagon levels). None of the diets were bioequivalent to the fasting condition and only the low carbohydrate diet gave comparable results. A strong relationship was found between the carbohydrate intake (in g) and the AUC of the various markers except glucagon.

Novel glyceride gels II. Viscosity characteristics.

Synopsis A gelling process for glycerides (synthetic or natural) by a cellulose derivative has been developed to obtain transparent oleogels of different consistencies. The present work examines the rheological behaviour of these oleogels. The study was carried out with a Trombomat Viscosity Follower. This measurement system allowed the determination of the gelling time and viscosity changes as a function of temperature.

In vivo evaluation of an indomethacin monolithic, extended zero-order release hard-gelatin capsule formulation based on saturated polyglycolysed glycerides.

The sustained release properties of an indomethacin hard-gelatin capsule formulated with saturated polyglycolysed glycerides (Gelucire) were demonstrated in vivo. Indomethacin was selected as a model drug with very poor solubility in water and acidic media. It is known to exhibit high intersubject variability because of enterohepatic circulation. The formulation, which in vitro showed an erosion-controlled release, was compared in six human volunteers in the fed state by using a randomized cross-over design, to a standard multiple-unit diffusion-controlled pellet capsule. Close action period values (time duration with plasma levels higher than 0.5 micrograms/ml) were found for the test and the reference formulation (5.2 and 5.7 h). The time to reach peak t(max) appeared slightly shorter for the test preparation (1.75 h) than for the reference formulation (2.67 h), but the difference was not statistically significant because of the high intersubject variability (non-parametric Wilcoxon matched pair test). Again, due to the small number of subjects entered in the study (insufficient for a real bioequivalence study) equivalence could not be accepted in terms of extent and rate of absorption based on the decision procedures involving the 90% confidence interval and the two one-sided t-tests. The mean maximum plasma concentrations Cmax were 3.35 and 2.82 micrograms/ml for the test and the reference formulation respectively, with the corresponding values of the area under the plasma concentration-time curve AUC amounting to 10.14 and 11.38 micrograms h/ml. However, a simulation on 24 subjects (3 repetitions of the same data) would lead to bioequivalence of the two preparations. As for other corrosion-controlled forms, drug release from the proposed Gelucire formulation was very sensitive to hydrodynamic conditions, leading to poor in vitro-in vivo correlation, when comparison is made with a reference formulation characterized by a diffusion-controlled release. Finally, it was concluded that erosion-controlled release formulations are especially suitable for drugs, such as indomethacin, that have low solubility in water or acidic media. More generally, sustained release hard gelatin capsules with thermosetting excipients is very versatile and their preparation is very straightforward.

Influence of food on the disposition of the antidiabetic drug metformin in diabetic patients at steady-state.

The effect of food on the bioavailability of the antidiabetic drug metformin (Glucophage, Lipha Laboratories) was investigated in patients at steady-state. Seventeen diabetic patients (5 males and 12 females) treated with a long-term metformin therapy received their morning dose after an overnight fasting or after each of four types of breakfast: low protein, low fat, low carbohydrate or standard. Mean (+/- SD) and median areas under the serum concentration curves (AUC), maximum concentrations (Cmax) and time to reach the Cmax (Tmax) were calculated. Compared to fasting conditions, AUC and Cmax for metformin were bioequivalent after the four types of breakfast except the low fat (high carbohydrate) diet which had results slightly reduced (90% CI = [0.76-0.90]). The intraindividual variability was calculated and found to be lower than the interindividual variability.

Gas chromatographic-mass spectrometric determination of isosorbide 5-mononitrate in human plasma.

A highly specific and precise method using gas chromatography-mass spectrometry was developed for the measurement of isosorbide 5-mononitrate in plasma using isomannide mononitrate as internal standard. With regard to the numerous analytical problems encountered when organic mononitrates were determined in plasma, such as thermal instability and adsorption, compounds were silylated before gas chromatography. In order to increase the specificity of the assay, two specific ions of the isosorbide 5-monitrate were simultaneously recorded. The accuracy of the assay was tested day to day with quality specimens spiked blind to the analyst.

Determination of oxeladin in human plasma by gas chromatography--mass spectrometry.

A capillary gas chromatographic method with mass-selective detection was developed for the determination of oxeladin in human plasma. Plasma samples (1 mL) were alkalinized and extracted using 5mL of hexane: isoamyl alcohol (99:1). The method was demonstrated to be sensitive (limit of quantitation at 1 ng/mL), linear between 1 and 150 mg/mL, accurate and precise enough (mean error and mean coefficient of variation at the limit of quantitation were 2.3 and 13.3%, respectively) to support pharmacokinetic evaluation of the drug at doses down to 30 mg.