Acta pharmaceutica Nordica最新文献

The disposition of alprazolam in 16 young healthy volunteers (eight females and eight males) was investigated. All volunteers were given a 1 mg dose of alprazolam. Dose/kg was 13.3 micrograms/kg (SD +/- 0.89 micrograms/kg) on average for male volunteers and 17.5 micrograms/kg (SD +/- 1.84 micrograms/kg) for the female volunteers. Pharmacokinetic parameters were calculated separately for both sexes in order to detect possible gender-dependent differences. The elimination rate constant (beta) for alprazolam proved to be significantly higher in the female population 0.067 hr-1 vs. 0.053 hr-1 (p = 0.03). The closely related parameters, elimination half-life (t1/2) and clearance (Cl) were also significantly different. The total area under the serum concentration curve (AUCtot), maximum serum concentration (cmax) and volume of distribution (Vd) were not significantly different. AUCtot corrected for differences in dose/kg was on the other hand significantly higher in males (p = 0.003) while cmax corrected in the same manner was not.

1-Phenylalkylindole-3-carboxylic acids 1-4, indole-1-acetic acids/esters 5-10 and the hydrazones 11-15 were prepared and submitted to the rat paw edema test using carrageenin. In the first two groups of compounds, the 2-chloro indoles were more active than the corresponding indole derivatives. In the third group the activity seemed to be determined largely by the substituent at the 1-position.

A study of pholcodine metabolism in man is reported. Three subjects received a single therapeutic oral dose of 50 mg pholcodine and urine samples were collected as long as a positive opiate response could be detected by EMIT (16-26 days). Pholcodine was found to conjugate with glucuronic acid and 15% (13-17%) of the pholcodine dose was excreted in urine as the glucuronide, and 29% (24-35%) as unconjugated pholcodine. Morphine was detected to be a metabolite of pholcodine and 0.5-1% of the pholcodine dose was excreted as morphine glucuronide. The identity of morphine was confirmed by capillary gas chromatography-mass spectroscopy (GC-MS).

Initial velocities of ketoprofen formation from ketoprofen-dextran ester prodrugs incubated in homogenates of various segments of the pig GI-tract were determined. Enzyme-mediated drug release was found in caecum and colon homogenates with their contents, whereas release rates in the stomach, duodenum, jejunum and ileum homogenates were comparable to those determined in pure buffer solutions of identical pH. In colon homogenates adjusted to various pH values between 6.0 and 7.9, little variation in release rates was observed. However, the contribution of enzyme-catalyzed drug regeneration to the overall initial velocity of ketoprofen formation increased significantly as a function of decreasing pH. The presence of several antibiotics and betamethasone in colon homogenates did not affect the drug activation process, whereas the addition of various enzyme inhibitors slowed down the ketoprofen release rates. During incubation in colon homogenates the average molecular weight of the dextran esters decreased. The drug release may therefore involve an initial fragmentation of the drug-liganded dextran chains carried out by dextranases secreted from the microflora which reside in the pig's large bowel.

Metabolites isolated from human plasma after oral administration of norethisterone were assayed as their novel dimethylethylsilyl ether derivatives by gas chromatography--mass spectrometry--ion selective monitoring. The major metabolite is 3 alpha, 5 alpha-tetrahydronorethisterone. The unchanged drug is present in a measurable amount even after 8 h of drug administration. The method is accurate, precise and highly sensitive.

Specific, sensitive, reverse-phase high-performance liquid chromatographic (HPLC) assays of 3,4-methylenedioxymethamphetamine (MDMA) and 3,4-methylenedioxyamphetamine (MDA) have been devised with analytical sensitivities as low as 2.7 ng/ml of plasma for MDMA and 1.6 ng/ml for MDA, using spectrophotometric detection at 280 nm. The assays were used to determine some properties of MDMA and MDA. Both drugs were stable in aqueous 1 M HCl, and 1 M NaOH solutions at room temperature. The half-life for MDMA was 6.6 h and for MDA was 7.1 h under the extreme conditions of 90 degrees C and 6 M HCl. MDMA and MDA were highly stable for 28 h in plasma at 25 degrees and 39 degrees C. The concentrations of the drugs were unchanged in frozen plasma after 47 days. The apparent red blood cell-plasma partition coefficient determined from assayed concentrations of the drugs in plasma and erythrocytes was 1.45 for both MDMA and MDA. An equation is presented to correct drug concentration in erythrocytes for the trapped equilibrated plasma/buffer in the packed red blood cells. The fraction of MDMA and MDA bound to dog plasma proteins was determined by several methods and it is 0.34-0.40 for both drugs. The extent of protein binding was independent of the drugs' concentration.

The bioavailability of ketoprofen after oral administration of aqueous solutions of various ketoprofen-dextran ester prodrugs in pigs was assessed. Conjugates derived from dextran fractions in the molecular weight range 10,000-500,000 were employed. Compared to the administration of an oral solution of an equivalent dose of parent ketoprofen, the average absorption fractions for the different prodrugs ranged from 100 to 67%. Relatively small inter-individual variation of ketoprofen bioavailability was observed. Apparently, the molecular size of the employed dextran transport group only has a minor influence on the pharmacokinetic parameters. The ketoprofen plasma profiles for all the administered prodrugs exhibited a characteristic lag time of ketoprofen appearance in the blood (2-3 h). Quite similar results were obtained from identical experiments carried out in the pig, employing naproxen-dextran esters. Thus, the present study adds support to a more versatile application of the dextran ester prodrug approach to providing selective colon delivery of drugs possessing a carboxylic acid functional group.

The in vitro dissolution rates of enteric-coated pellets and tablets containing dexchlorpheniramine maleate (DCPM) were obtained using the USP XXI paddle and a flow-through method. Pellets were produced by extrusion and spheronization. Tablets were produced by direct compaction, and by wet granulation. The products were coated with different amounts of Eudragit L30D using fluid-bed technology. Onset of release, determined by fitting of the Weibull function, was the only factor found to be affected by the amount of coating of the tablets. For pellets, both onset of release and dissolution rate showed significant differences. Scanning electron microscopy was used to study the effect of different dissolution media on the coating. Acidic medium was found to alter the coating surface, but the coating did not rupture during the time used in this study.