Determination of levamisole and tetramisole in seized cocaine samples by enantioselective high-performance liquid chromatography and circular dichroism detection.

Levamisole, an anthelmintic drug, has been increasingly employed as an adulterant of illicit street cocaine over the last decade; recently, the use of tetramisole, the racemic mixture of levamisole and its enantiomer dexamisole, was also occasionally observed. A new enantioselective high-performance liquid chromatography (HPLC) method, performed on cellulose tris(3,5-dimethylphenylcarbamate) chiral stationary phases in normal-phase mode, was validated to determine the enantiomeric composition of tetramisole enantiomers in seized cocaine samples. Furthermore, the hyphenation of the validated HPLC method with a circular dichroism (CD) detection system allowed the direct determination of elution order and a selective monitoring of levamisole and dexamisole in the presence of possible interferences.

Determination of dextromethorphan and levomethorphan in seized heroin samples by enantioselective HPLC and electronic CD.

A new enantioselective HPLC method was developed for the resolution and determination of the enantiomers of methorphan, dextromethorphan (DXM) and levomethorphan (LVM), on a Chiralcel OJ column (250 mm × 4.6mm I.D.

Stereochemical characterization of fluorinated 2-(phenanthren-1-yl)propionic acids by enantioselective high performance liquid chromatography analysis and electronic circular dichroism detection.

Enantioselective high performance liquid chromatography (HPLC) coupled with a detection system based on the simultaneous measurement of UV absorption and electronic circular dichroism (ECD) allows a complete stereochemical characterization of chiral compounds, once the relationship between sign of the chiroptical properties and absolute configuration is determined. In the present communication, the development of enantioselective HPLC methods for the resolution of a series of fluorinated 2-phenanthrenylpropionic acids (1-6) is reported. Different chiral stationary phases (CSPs) were tested: Chiralcel OJ, Chiralcel OD, Chiralpak AD, (S,S)-Whelk-O 1, Chirobiotic T and α(1)-acid glycoprotein (AGP).

Albumin nanoparticles carrying cyclodextrins for nasal delivery of the anti-Alzheimer drug tacrine.

Peroral administration of tacrine, the first acetylcholinestearse inhibitor licensed for the treatment of Alzheimer's disease, is associated with low bioavailability, due to an extended first-pass methabolism, short elimination half-life and hepatotoxicity. Nasal drug delivery may reduce the degree of these problems. Tacrine hydrochloride nasal delivery is here investigated by means of albumin nanoparticles carrying beta cyclodextrin and two different beta cyclodextrin derivatives (hydroxypropyl beta cyclodextrin and sulphobutylether beta cyclodextrin).

New environmental sensitive system for colon-specific delivery of peptidic drugs.

Nano and micro preparative technologies for the realization of pharmaceutical carriers represent an actual strategy for reaching the therapeutic success of drugs, particularly in the case of peptidic drugs. Vancomycin is here entrapped in carriers composed by a swellable, mucoadhesive and biodegradable albumin core, coated with fatty acids able to improve a colon-specific release. Bovine serum albumin nanospheres (core) were prepared from protein solutions using a coacervation method followed by thermal cross-linking at different temperature, or from protein solutions at different pHs using a coacervation method followed by thermal cross-linking at 75 degrees C.

Determination of 10 sulfonamide residues in meat samples by liquid chromatography with ultraviolet detection.

A liquid chromatography (LC) method is described for the simultaneous determination of 10 commonly used sulfonamide drug residues in meat. The 10 sulfonamide drugs of interest were sulfadiazine, sulfathiazole, sulfamerazine, sulfadimidine, sulfamethizole, sulfamonomethoxine, sulfachloropyridazine, sulfadoxine, sulfadimethoxine, and sulfaquinoxaline. The residues were extracted with acetone-chloroform (1 + 1).

Enhanced release of indomethacin from Pvp/stearic acid microcapsules prepared coupling Co-freeze-drying and ultrasound assisted spray-congealing process.

Purpose: Fast releasing indomethacin microparticles were prepared encapsulating co-freeze-dried indomethacin/poly(vinylpyrrolidone) particles (IMC/PVP) into molten stearic acid (SA), by means of a ultrasonic spray-congealing technique.

Materials And Methods: IMC particles were suspended in a PVP aqueous solution and the system was then freeze-dried. A suspension was prepared from the co-freeze dried IMC/PVP powder into molten SA that was then atomized into small droplets using ultrasound.

GC/MS evaluation of thyme (Thymus vulgaris L.) oil composition and variations during the vegetative cycle.

Capillary GC/MS analysis based on polar and non-polar columns has been applied to evaluation of the volatile oils hydrodistilled from thyme (Thymus vulgaris L.) plants. The adopted methodology has been used to monitor seasonal variations in the composition of the oil obtained from thyme herbs harvested at different periods during the plant vegetative and life cycles.