Vial Surface Research Articles

Zur Stabilit�t hochverd�nnter Multielement-Eichstandardl�sungen ? Erfahrungen mit ICP-MS

The long term stability of self prepared multielement calibration solutions, which is of fundamental importance in ultra trace element analysis with ICP-MS, has been tested. Solutions with element concentrations of 10 ppb, 50 ppb, 100 ppb and 500 ppb in different aqueous matrices have been analyzed immediately after preparation and after 1, 3, 10, and 30 days of stockage in usual glass vials. For analysis with a VG Plasmaquad, the pH of all solutions was adjusted to ca. 1. The results showed that even very low element concentrations of the majority of elements investigated in this study remained stable in acidic aqueous solutions over a period of 30 days. For boron, silver, gold, and tantalum significant changes of the initial concentrations have been observed dependent on stockage time. Decrease of element concentrations is due to adsorption on the surface of the glass vials and probably to photochemical oxidation. A considerable increase of the concentrations of all investigated boron-containing solutions even after a short stockage time is due to mobilization of boron from the glass of the vials. However, adsorption effects are of insignificant importance even for critical elements such as B, Br, I, Pb, and are largely dependent on the pH of the diluted solutions. Solutions with concentrations of a large number of elements in the range even below 1 ppm can be stocked as multielement standards for 30 days, if the pH of the solutions is not higher than 1.

Sensitive high-performance liquid chromatographic analysis for chloroquine in body fluids application to studies of drug resistance in plasmodium falciparum

A high-performance liquid chromatographic method has been developed for the sensitive determination of chloroquine in body fluids. The method has been applied to quality-control assay of World Health Organization (WHO) In-Vitro, Macro-Test Kits for the assessment of susceptibility of Plasmodium falciparum to chloroquine. Experiments utilizing [ 14C]chloroquine demonstrated that water was not capable of efficiently desorbing chloroquine from the inside surfaces of kit vials. The addition of blood to the vials effectively desorbs chloroquine. Subsequent addition of the blood to aqueous base followed by hexane extraction permits quantitation by reversed-phase, ion-pair high-performance liquid chromatography utilizing ultraviolet detection at 344 nm. The method is capable of determining as little as 20 ng of chloroquine per vial. This method, utilizing the methyl other of 9-anthracenemethanol as internal standard, can quantify chloroquine in 1 ml of blood or urine with a minimum detection limit of 20 ppb 1 1 Throughout this article, the American billion (10 9) is meant. (ng/ml). Measurement of blood levels of chloroquine in persons contracting falciparum malaria while following a prophylactic regimen complements in-vitro drug susceptibility measurements in characterizing resistant strains of the parasite.

Inhibition of Adherence of Streptococcus mutans to Glass Surfaces

Maltose and low-molecular weight dextran inhibited the adherence of Streptococcus mutans to the smooth glass surface of scintillation vials. Inhibition of adherence paralleled inhib

Glass for Parenteral Products: A Surface View Using the Scanning Electron Microscope

AbstractThe scanning electron microscope was utilized to explore the internal surface of glass ampuls and vials used in parenteral products. The surface topography of USP Type I borosilicate glass containers was viewed after exposure to “sulfur,” ammonium bifluoride, and sulfuric acid treatments. The scanning electron micrographs showed startling differences in the appearance of the surface regions. “Sulfur treatment” of ampuls was associated with a pitting of the surface and the presence of sodium sulfate crystals. The sulfur treatment of vials altered the glass surface in a characteristically different manner. The dissimilarity between the surface appearances was attributed to the method of sulfur treatment. Ampuls exposed to sulfuric acid solutions at room temperature did not show the pitting associated with the sulfur treatment. Scanning electron micrographs of ammonium bifluoride‐treated ampuls showed a relief effect, suggesting that the glass was affected by the bifluoride solution but that sufficient stripping of the surface layer did not occur to remove the pits associated with the sulfur treatment. Flakes emanating from the glass were identified with the aid of the electron microprobe. Scanning electron micrographs showed that these vitreous flakes resulted from a delamination of a thin layer of the glass surface. It is concluded that the scanning electron microscope, in conjunction with other analytical techniques, is a valuable tool in assessing the quality of glass used for parenteral products. The techniques studied should be of particular importance to the pharmaceutical industry where efforts are being made to reduce the levels of particulate matter in parenteral dosage forms.

Vial retention of technetium-99m sulfur colloid in commercial kits

Vial retention of technetium-99m sulfur colloid in five commercial kits used for the preparation of this radiopharmaceutical was studied. Radiochromatography and microscopic particle sizing were performed on all products; the biologic distribution in rats of two products was tested. Loss of activity attributable to vial retention was evident with only two products. The resulting loss of specific concentration did not affect biologic distribution. The cause of the "plating-out" of the radiopharmaceutical on the interior reaction vial surface was not determined, although the gelatin component of the product was suspected to be a factor.

Chapter 18 The Measurement of Radioactive Precursor Incorporation into Small Monolayer Cultures

Publisher Summary This chapter describes a straightforward and reproducible technique for measuring incorporation of labeled precursors into nucleic acids and proteins of small monolayer cell cultures. The cells are grown, treated, and processed and radioactivity is recorded while the cells are attached to the bottom surface of glass scintillation vials. Large numbers of replicates and/or treatment conditions can be used in one experiment, and no specialized culture vessels are required. Replicate samples for autoradiography are readily prepared. Radioactivity in the perchloric acid or sodium hydroxide extracts was recorded in a scintillation counter after addition of a Triton X-based scintillator (10 ml), giving a homogeneous solution. The scintillation fluid consisted of Triton X-100 (1000 gm), toluene (2000 ml), PPO (16.5 gm), and dimethyl-POPOP (300 mg). Although, it is quite feasible to correct samples for quenching by standard methods, and hence calculate disintegrations per minute, this proved superfluous. Quenching was consistent to within narrow limits between samples, and the method is comparative (that is, treated vs. control) only in the sense that nucleic acid (or protein) specific activities cannot be obtained.

Micro Radiometric Method for Study of Acid-insoluble Materials in Monolayer Cell Cultures

A simple radiometric procedure for study of acid-insoluble products synthesized in monolayer cell cultures is described. Cell cultures were produced directly on the bottom surface of scintillation vials or on glass cover slips (8 X 30 mm). The cells were labeled and extracted; the radioactivity was determined while the cells remained affixed to the glass surface upon which they were grown. This procedure enabled rapid investigations of certain biosynthetic processes to be carried out by using many individual cell cultures. The method was applied to an investigation of (3)H-thymidine incorporation induced by vaccinia virus in a 5-bromodeoxyuridine-resistant cell line. (14)C-labeling was evaluated as an alternate procedure for cell quantitation.

Micro radiometric method for study of acid-insoluble materials in monolayer cell cultures.

A simple radiometric procedure for study of acid-insoluble products synthesized in monolayer cell cultures is described. Cell cultures were produced directly on the bottom surface of scintillation vials or on glass cover slips (8 X 30 mm). The cells were labeled and extracted; the radioactivity was determined while the cells remained affixed to the glass surface upon which they were grown. This procedure enabled rapid investigations of certain biosynthetic processes to be carried out by using many individual cell cultures. The method was applied to an investigation of (3)H-thymidine incorporation induced by vaccinia virus in a 5-bromodeoxyuridine-resistant cell line. (14)C-labeling was evaluated as an alternate procedure for cell quantitation.