Carlo Gandini

Egg yolk riboflavin binding protein as a new chiral stationary phase in high-performance liquid chromatography

A chiral stationary phase for high-performance liquid chromatography based on hen egg yolk riboflavin binding protein is introduced. The purified protein was immobilized on activated 5NH2 Nucleosil silica. Chiral acidic, basic and uncharged drugs were chromatographed and the influence of the mobile phase parameters on the retention times and enantioselectivity was studied. Thirteen out of the twenty compounds tested were partially or baseline resolved. These encouraging preliminary results suggest that this chiral stationary phase may be applicable to a wide range of drug enantiomers in the reversed-phase mode.

Trends of organochlorine residues in eggs of birds from Italy, 1977 to 1985.

All the eggs, collected in Italy in 1982 and 1983, of two species of passerine birds, three gulls, four terns and the night heron, contained DDE and, with lower frequencies, other organochlorine contaminants. Organochlorines were more concentrated in the species of higher trophic level. DDE contamination showed a decreasing trend from 1978 to 1985 in one passerine, two terns and in the heron. After 1980-1982, the level of contamination was below the critical threshold beyond which reproduction is affected, eggshell thickness was only slightly or not reduced; therefore, the current impact of organochlorines on these birds is probably negligible. Detrimental effects may have occurred during the 1970s, when some of the eggs were contaminated beyond the critical threshold.

Exposure to heptachlor: evaluation of the effects on the larval and adult epidermis of Rana kl. esculenta.

Widely used in the past against termites and soil insects, the chlorinated insecticide heptachlor (H) is a toxic contaminant which represents a risk for both terrestrial and aquatic organisms. Like many organochlorine pesticides, heptachlor and heptachlor epoxide (HE), with oxidation products synthesized by many plant and animal species, degrade slowly since many of the derived compounds are persistent. This increases the status of heptachlor as a hazardous pollutant. In the present experimental study we exposed specimens of Rana kl. esculenta, from the tadpole stage through to their complete metamorphosis, to three different concentrations of heptachlor (4, 40 and 400 ppb). Mortality and HE bioaccumulation were evaluated on all the experimental groups. Since amphibian integument directly interacts with the environmental constituents (water, air and soil), we investigated the toxic effects on the ventral epidermis of both tadpole and adult samples by employing such histo-cytopathological biomarkers as ultrastructural morphology, certain enzyme activities (acid and alkaline phosphatases, AcPase, and AlkPase; succinic dehydrogenase, SDH; alpha-naphtyl butyrate esterase, ANBE; nitric oxide synthase/NADPH diaphorase, NOS/NADPHd). Also, the levels of reactive oxygen species (ROS) in the different conditions were evaluated. The results obtained were of ecological relevance, in particular as regards the effects of this environmental toxicant on the samples of tadpole epidermis. Severe morphological alterations were observed in the larval epidermal cells (apical and skein cells), whereas the cell epidermis (keratinocytes and mitochondria-rich cells) of the adult survivors showed changes in enzyme activities, particularly those involved in the protective response to xenobiotic injury. In general, morpho-histochemical studies, analysis of HE bioaccumulation and mortality showed a relation to the H doses employed.

Mortality and tissue damage by heavy metal contamination in the German cockroach, Blattella germanica (Blattaria, Blattellidae)

Abstract The accumulation of lead, cadmium, mercury, and chromium, supplied in the diet under experimental conditions, was studied in adult German cockroaches. Chronic heavy‐metal exposure de termined different rates of mortality, higher in males than in fe males. In both sexes, Hg, Pb, and Cr bioaccumulated in time, whereas Cd remained at constant low concentrations. Histological studies showed that in some organs and structures, such as the ovary, the testis, the alimentary canal and the fat bodies, there were profound and irreversible pathological anomalies in their tis sues. Also the embryos of some treated females suffered heavy damage during development, and the symbiotic relationships be tween bacteria and fat body cells were deeply altered.

High-performance liquid chromatography post-column derivatization with fluorescence detection to study the influence of ambroxol on dipalmitoylphosphatidylcholine levels in rabbit eustachian tube washings

In this work an appropriate high-performance liquid chromatography method was set up to guarantee specificity, sensitivity, precision and accuracy in analyzing dipalmitoylphosphatidylcholine (DPPC) in rabbit eustachian tube washings, as well as to determine its varying levels after administration of ambroxol chloride. The procedure is based on a post-column derivatization with fluorescence detection using 1,6-diphenyl-1,3,5-hexatriene which exhibits increased fluorescence in a lipid environment. DPPC was chromatographed on a Hypersil C18. The mobile phase for the isocratic elution consisted of 40 mmol/l choline chloride in methanol-tetrahydrofuran (97:3). Ambroxol was given to a group of New Zealand white rabbits at a dose of 30 mg/kg. A second group receiving vehicle only acted as controls.

Determination of 5-aminosalicylic acid and related compounds in raw materials and pharmaceutical dosage forms by high-performance liquid chromatography

Abstract A high-performance liquid chromatographic method using a μBondapak C 18 column and a UV detector at 230 nm was developed for the simultaneous determination of 5-aminosalicylic acid (5-ASA) and related compounds (4-aminophenol, 3-aminosalicylic acid and 3-aminobenzoic acid). A method for the determination of 5-ASA in pharmaceutical preparations (tablets, granules and rectal suspension) is also described. Calibration graphs for both 5-ASA and related compounds are reported. The standard deviation is ± 0.623 ( n = 10).

High-performance liquid chromatographic determination of α-tocopheryl nicotinate in cosmetic preparations

alpha-Tocopheryl nicotinate (alpha-TN) accelerates blood circulation and stimulates hair follicle cells, hence it is an active ingredient in a broad range of cosmetic products. A reversed-phase high-performance liquid chromatographic method was developed to determine alpha-TN in cosmetic preparations with alpha-tocopheryl acetate as internal standard. The method was found to be rapid, precise and specific.

Reversed-phase high-performance liquid chromatographic and derivative UV spectrophotometric determination of α-phenylethylamine in phosphomycin

Abstract Two sensitive and selective methods were developed for the evaluation of α-phenylethylamine (α-PEA), an impurity possibly present in the antibiotic phosphomycin (PHO). The reversed-phase high-performance liquid chromatographic method uses a LiChrosorb NH2 column with acetonitrile-0.1M NaH2PO4 · H2O buffer as eluent and allows the simultaneous detection of PHO and α-PEA in a complex matrix such as pharmaceutical preparations. The amine gives a linear detection response over the range 15–85 μg/ml. The derivative spectrophotometric method can specifically discriminate the amine in the range 230–280 nm. The α-PEA concentration is determined by measuring the distance between the maximum at 250 nm and the adjoining minimum at 248 nm in the second-derivative spectrum. A linear correlation was found in the concentration range 15–160 μg/ml. For both procedures, no sample pretreatment is required.

Differential retention of PCB congeners in cockroaches Blattella germanica.

Organisms differ widely in their ability to metabolize and eliminate polychlorinated biphenyls (PCBs). We evaluated the retention of PCB congeners, reference standard mixture, experimentally injected into cockroach Blattella germanica, in relation to sex and time, and its elimination through the feces, exuviae and oothecae. The nymphs that died prematurely had a higher average PCB retention than those with a longer lifetime, 88% of the injected dose for those that died within 1 to 10 days, and 76% for those within 11–20 days. Diverse PCB congeners showed differential retention, and particularly the more volatile, low weight congeners were recovered in lower concentrations, the medium-weight ones were intermediate, while the high-weight congeners attained the highest concentration. PCBs were also detected in the excrements and in exuviae, which may therefore act as detoxification paths, and in the oothecae, thus showing that PCBs can be transferred from mother to progeny.

Development of an ion-pair HPLC method for the determination of 2,4- and 2,6-toluendiamine in human plasma

SummaryAn ion-pair HPLC method is presented for the determination in plasma of 2,4- and 2,6-toluendiamine (TDA), known carcinogens. The chromatographic conditions consisted in isocratic elution on a reversed phase C18 column with 5 mM octanesulfonic acid in methanol-water, 45∶55, as mobile phase. UV detection was performed at 235 nm. Samples were analyzed after a simple single step liquid-liquid extraction and the method was validated by measurement of precision (interassay and intraassay), sensitivity, specificity, linearity, and recovery. The detection limit for both TDAs in plasma was 20 ng mL−1. The correlation coefficients based on the intrassay calibration curve were 0.998 and 0.997 for 2,6- and 2,4-TDA, respectively. The intraassay accuracy, expressed in terms of recovery, was found to be up to 89.91% and 97.05% for 2,6- and 2,4-TDA, respectively.