Pharmaceutica acta Helvetiae最新文献

A formulation for fast dispersible granules with the magnetic resonance (MR) contrast agent, Oral Magnetic Particles (OMP), was developed. The formulation contained viscosity-increasing agents (xanthan gum and a mixture of microcrystalline cellulose and sodium carboxymethylcellulose). The granules were dispersed easily in water when stirred by hand and became a viscous OMP suspension with apparent homogeneity, but does not form granule aggregates (lump), within 10 min. The dispersibility was greatly affected by the binder type and addition of disintegrant. Hydroxypropylcellulose and low-substituted hydroxypropylcellulose were preferable. The preparation method to incorporate OMP into the granules also greatly influenced the dispersibility of the granules. A fluidized bed granulation of the base granules containing additives and subsequent coating of OMP onto the granules was eventually utilized. The formulation was able to control the viscosity of the suspension by regulating the content of viscosity-increasing agent while maintaining dispersibility. The developed formulation gave a good MR contrast image in rats and no magnetic susceptibility artifact was observed.

A new, simple and accurate high-performance liquid chromatography (HPLC) method is presented for measuring of quinapril in tablets, using a reversed-phase technique and UV detection at 211 nm. The isocratic elution was used to quantify the analyte and the internal standard-perindopril. The samples were chromatographed on LiChrosorb RP-18 column and the mobile phase was phosphate buffer pH 2.5-acetonitrile (6:4, v/v). The method was linear between 0.1–0.5 mg ml⁻¹. Over the tested concentration range the intra-day coefficient of variation for replicate analyses in tablets ranged from 0.88 to 2.70%. The detection limit for the analysis of quinapril was 50 μg ml⁻¹ with 20 μl injection.

Sustained release casein–chitosan microspheres containing diltiazem hydrochloride (DTZ) were prepared with colloidal coacervation technique in a completely aqueous environment. The interaction between chitosan solution in dilute acetic acid (5% v/v) and casein solution in 0.5 M sodium hydroxide was the basis for the microspheres formation. Formaldehyde was used for the surface hardening of the droplets by cross-linking and thus fixing the shape and surface morphology of the formed microspheres. The entrapment efficiencies of the microspheres were variables (14.5–53.7%) depending on the preparation conditions. The prepared microspheres exhibited an angle of repose values between 31.9–42.0° indicating good free flowing nature, whereas DTZ powder as such was non-flowable. The dissolution profiles of DTZ from casein–chitosan microspheres showed retarded release pattern of the drug into distilled water. Casein and chitosan concentrations, initial drug concentration and stirring time were found to be the main parameters that affect the properties and the performance of the prepared microspheres. The retarded release of DTZ was increased by increasing casein concentration, and stirring time. On the other hand, increasing chitosan concentration and using high initial drug loading showed a fast drug release.

An accurate and specific PMR method for the determination of vincamine in the bulk drug, as well as solid and liquid dosage forms has been developed. The determination is based on the integration of the three methyl protons of the CH₂–CH₃ group of vincamine, relative to that of the two noncarboxylic protons of maleic acid (internal standard). The method furnishes a specific means of identification of vincamine as well as the simultaneous detection of the possible presence of other alkaloids.

The ever increasing data available on antigen presentation by class I or class II histocompatibility proteins have made these glycoproteins highly interesting pharmaceutical targets for either vaccination or immunosuppressive therapy of autoimmune diseases and cancers. Herewith, we review the design and biological properties of the very first nonpeptide ligands of major histocompatibility proteins as well as their potential application in vaccination, Major Histocompatibility Complex (MHC) blockade or T cell receptor antagonism.

Lipid microspheres (LM) of indomethacin were prepared using phosphatidyl choline and soya bean oil. LM of required size (<1 μm) were obtained by intermittent microscopic observation while homogenization. Anti-inflammatory activity of lipo-indomethacin was compared with free indomethacin by carrageenan induced rat paw edema model. It was found that at 30% edema inhibitory dose, lipo-indomethacin was about 1.5 times more potent than free indomethacin, indicating possible localization of LM at the inflammatory site. Biodistribution studies were performed in rats at the dose of 12 mg/kg. After 2 h of the treatment, concentration of the drug was 0.31 μg/g of inflammatory tissue with lipo-indomethacin, whereas, only 0.05 μg/g of the tissue was found with free indomethacin. Maximum difference in drug concentrations between the above two formulations was observed in lungs. LM were found not to cross the BBB as drug concentration in the brain after lipo-indomethacin treatment was below the detectable level. Thus, the pharmacokinetic data gave a quantitative evidence for high anti-inflammatory potential of lipo-indomethacin.

The thioureido derivative of 4-aminoacetophenone aryl semicarbazone have been prepared. These derivatives have been characterised on the basis of different physicochemical evidences. The anti-HIV-1 (HTLV-III_B) and -HIV-2 (ROD) activity and cytotoxicity of the compounds were tested. The compound VII and VIII showed maximum protection among the series.

The authors propose 2-(3,4-dihydroxyphenylazo-1)-benzimidazole (BIAP); 3-mercapto-5-2-(3,4-dihydroxyphenylazo-)-1,2,4-triazole (METRIAP) and 2-carboxymethanotio-5-(3,4-dihydroxyphenylazo-1)-1,3,4-tiadiazole (TIDAP-SO) for spectrophotometric determination of trace amounts of Fe(II) in the presence of microamounts of other elements [Ca(II), Cu(II), Mn(II), Zn(II), Mg(II), Mo(III), P(V), S(VI)] without removing or sequestering them, and vitamins in pharmaceutical multivitamin preparations: Supradyn® and Vitapil®. The obtained results were statistically analysed and compared with those of atomic absorption spectrophotometry (AAS). The advantage of the proposed method is good selectivity, precision and reproducibility of results.

Turchi et al. [Turchi, P., Canale, D., Ducci, M., Nannipieri, E., Serafini, M.F., Menchini Fabris, G.F. (1992). The transdermal route in the treatment of male sexual impotence: preliminary data on the use of yohimbine. Int. J. Impotence Res. 4, 45–50.] showed that the application on penile skin of an oil-in-water cream (cream I.G) containing yohimbine (YO) was successful in the treatment of male sexual impotence. The components of the cream were stearyl alcohol, isopropyl lanolate, white petrolatum, liquid petrolatum, sodium lauryl sulphate (NaLS), propylene glycol (PG) and water. In the present study, a number of creams were derived from the cream I.G by adding, eliminating or replacing one or more constituents, and the effects of such changes on YO permeation through excised hairless mouse skin were investigated. From the data emerged the possibility of improving YO permeation even through slight changes in I.G composition. The stratum corneum-vehicle interactions were investigated by analyzing samples of isolated hairless mouse stratum corneum by DSC.