Acta pharmaceutica Nordica最新文献

The structure and absolute configuration of the title compound have been determined by single crystal X-ray diffraction analysis. The space group symmetry is R21; the monoclinic unit cell contains two molecules and has the dimensions a = 12.4291(8), b = 7.4511(5), c = 12.7854(7) angstroms and beta = 102.295(7) degrees. The planar conformation of the benzamide moiety is stabilized by an intramolecular (N)H...O bond. Hydrogen bonds connect the chloride anion to the protonated pyrrolidine N atom, and also the crystal water to the carbonyl oxygen of the amide group. The molecule has a folded conformation in which the N-fluorobenzyl substituent of the pyrrolidine ring and the H-bonded pseudo ring of the benzamide moiety are arranged in a sandwich-like manner. In the crystal, intermolecular hydrogen bonds link the drug molecules via the chloride anion and the hydrate molecule into endless helical chains around the twofold axis. The absolute configuration was determined by comparison of the wRtot values, 0.037 and 0.040, calculated using all measured 2027 unique, non-zero reflections and assuming R and S configuration for the chiral center, respectively. Refinement of the structural model with an R configuration resulted in the final indices of R = 0.031 and wR = 0.033 for 1512 reflections with I/delta(I) greater than 3.

The bioavailability of noscapine base administered in lozenges in a dose of 100 mg to twelve healthy volunteers, in a study using an open balanced cross-over design, was compared with that of 100 mg of noscapine hydrochloride given perorally as a mixture. The bioavailability of noscapine after administration in lozenges was significantly higher than that after administration of the drug as a mixture. It is concluded that the lozenges containing noscapine base may be a valuable alternative to the conventional noscapine hydrochloride mixture.

The simplex centroid design was applied to the optimization of a modified release tablet formulation. A base granulation was made with the active ingredient naftidrofuryl. The variables investigated included fractions of the excipients microcrystalline cellulose, lactose and dicalcium phosphate dihydrate. The release rate, crushing strength, friability and weight variation were determined as response parameters. Mathematical models were fitted to the data obtained by the lattice method, described by Scheffé and by means of multiple linear regression. Regression analysis indicated a relatively good fit of the models. On the basis of the regression models, contour plots were constructed. An increase in the amount of dicalcium phosphate caused lower release rate and increased weight variation. An increase in the content of lactose showed lower strength and increased friability, whereas an increase in the amount of microcrystalline cellulose had the opposite effect.

A quantitative structure-activity relationship (QSAR) for some 6-methoxybenzamides having 1-ethyl-2-pyrrolidinylmethyl side chains with respect to the inhibition of [3H]spiperone binding is established using the PLS method. An experimental design approach to select the training set compounds is demonstrated. The established relationship between structure and in vitro activity indicates the dominating influence of the substituents in the 3-position as well as the importance of (S)-configuration in the side chain. A methoxy substituent in the 5-position is also beneficiary for high activity. Both salicylamides and non-salicylamides could be accommodated in the analysis, which supports the notion of a common binding site in the receptor.

The main alkaloid in the roots of Thalictrum flavum is berberine. The alkaloids glaucine, thalicsimidine, thaliglucine, thalidazine, hernandezine and thalfoetidine were also isolated.

The stability of tauromustine in buffered aqueous solutions was investigated over the pH range 0.9-7.5. The pH rate profile at zero buffer concentration has a specific acid catalytic region at pH below 2, a plateau of pH-independent degradation between pH 2 and 4, and shows a sharp increase in the degradation rate at pH above 4. The activation parameters, the solvent isotope effect and the effect of the dielectric constant on the degradation rate were determined, and possible degradation mechanisms were discussed. The effects of six cyclodextrin (CD) derivatives on the stability of tauromustine in aqueous buffer solutions were investigated. All the CDs tested had some stabilizing effect on the drug at pH 1.98 and 4.06 but they had little or no effect at pH 6.38. Hydroxypropyl-alpha-cyclodextrin (HP alpha CD) had the largest stabilizing effect. Tauromustine degraded about 25 to 50% slower in aqueous buffer solutions containing 2% HP alpha CD compared to buffer solutions containing no CD.

Disodium cromoglycate particles were labelled with 99mTc by spray-drying technique. The in vitro dissolution profile as well as the leakage of radioactivity from the drug particles were determined using a through-flow cell method. The radioactive drug particles were mixed with a lactose carrier and inhaled from a dry powder device by five healthy volunteers. The removal of the inhaled drug particles from the lungs was evaluated by a gamma camera. A close relationship between the dissolution of the drug as such and the leakage of radioactivity was noted. Gamma scintigraphy indicated a biphasic exponential removal of radioactivity from the lung region. The slow component with the halftime of about 55 min was mainly due to the dissolution of drug particles in the lungs. The halftime of the fast component describing mucociliary clearance was less than 10 min. This process was the dominating one for the removal of the drug from the lungs. The experiment thus showed that the main fraction of the inhaled dose was deposited in the tracheobronchial region. Accordingly, only a small portion of the dose initially deposited in the lung can be absorbed and induce a therapeutic effect.