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 µg ml−1 (the concentration reached 3 h after application of the oral gel according to published data) or above 1.0 µg 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 µg 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.
The in vitro diffusion of progesterone from a gel formulation using the European Pharmacopoeia method for transdermal dosage forms is described. The membranes used were the dorsal and ventral ...portions of the shed skin of three different species of snake. Considerable differences are apparent between the dorsal and ventral sites and between the different species of snake. The dorsal area shows better permeability for progesterone and the permeability order for the different species is python>cobra>viper. These differences may be due to the thickness of the skin and the hinge:scale ratio. The results indicate that shed snake skin is not a model membrane for human skin.
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.
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.
The aim was to study a new method of dissolution in vitro, the "Bio-Dis" apparatus, and to compare it with the classical rotating bottle method. Several theophylline controlled-release drug dosage ...forms were studied. Dissolution testing was performed in increasing pH in standard conditions and after treatment with peanut oil in order to simulate high fat meals and to correlate the in vitro percent dissolved with the in vivo results obtained. The in vivo study was carried out on three groups of healthy volunteers receiving each dosage form in a randomized order just before a high fat breakfast or in the fasting state. The in vitro percent dissolved obtained was compared with those published results obtained with rotating bottles. A linear relationship was established between these results. From the in vivo absorbed percentages calculated according to the Wagner-Nelson method, a linear relation was found between the in vivo percent absorbed and the in vitro percent dissolved in the different conditions. The relationships observed are similar for all the forms under both conditions. The "Bio-Dis" offers advantages over the rotating bottle method. The study reported allows this dissolution apparatus to be proposed as an alternative to the rotating bottle apparatus.
Abstract
The characteristics of poly (2-hydroxyethyl methacrylate) matrices for the controlled release of drugs have been investigated using methotrexate (MTX) as a model drug. Radiation-induced ...polymerization of hydrophilic monomers (HEMA and related compounds) at low temperature (-78°C) was performed to immobilize MTX in the polymer matrix. The effect of the drug loading and diflerent amounts of cross-linking agent on the in vitro drug release was studied in this work. The diffusion of MTX from the hydrogel matrices was proportional to the square root of the time, according to the equation proposed by Higuchi (1).
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.
PDF
