Method for the determination of residual formaldehyde in an inactivated Zika vaccine formulated with aluminum hydroxide gel.

A simple method for the determination of low levels of residual formaldehyde in an inactivated Zika vaccine formulated with aluminum hydroxide gel was developed for the assessment of drug product quality. Formaldehyde was reacted with 2,4-dinitrophenylhydrazine (DNPH) and the derivatized product was detected by HPLC with an UV detector at 360 nm. The derivatization reaction could be carried out in a 2-mL HPLC vial and the sample was analyzed directly. The method was fully validated according to the International Conference on Harmonization Q2 guidelines. Aluminum hydroxide gel up to 1.0 mg/mL (aluminum concentration) did not interfere with the determination of formaldehyde in drug product. Formaldehyde concentrations of 0.05 µg/mL (quantitation limit) to 1.00 µg/mL in the Zika vaccine could be precisely determined. Hence, this method proved to be suitable for quality control of the Zika vaccine.

Accelerated biosynthesis of neolacto-series glycosphingolipids in differentiated mouse embryonal carcinoma F9 cells detected by using dodecyl N-acetylglucosaminide as a saccharide primer.

Using dodecyl N-acetylglucosaminide (GlcNAc-C12) as a saccharide primer, we investigated the biosynthetic changes of neolacto-series glycosphingolipids (GSLs) in mouse embryonal carcinoma F9 cells during differentiation induced by retinoic acid plus dibutyryl cyclic AMP (RA/dbcAMP). In the differentiated cells, the glycosylation of GlcNAc-C12 was greatly enhanced. The sugar compositions of glycosylated primers were assigned as Hex-GlcNAc, [Hex](2)-GlcNAc, [Hex](2)[HexNAc]-GlcNAc, and [NeuAc][Hex]-GlcNAc by liquid chromatography-tandem mass spectrometry. The detection of augmented biosynthesis of endogenous sialylparagloboside indicated that [NeuAc][Hex]-GlcNAc was predicted to be the non-reducing end trisaccharide of sialylparagloboside. The transcription of B3gnt5, B4galt1, Ggta1, Fut4 and St3gal6, encoding glycosyltransferases involved in the neolacto-series glycosphingolipids biosynthesis, was increased, whereas that of Fut9 and St6galI was decreased after RA/dbcAMP treatment. Furthermore, the sialyltransferase activity of ST3GalVI sialylating paragloboside was enhanced with the increase in St3gal6 expression. Since most stage-specific embryonic antigen-1 (SSEA-1) active determinants are carried by glycoproteins in F9 cells, the changes in glycolipid metabolism do not seem to be closely related to loss of cell surface SSEA-1 expression upon F9 differentiation. These results indicate that RA/dbcAMP treatment activates the biosynthesis of neolacto-series GSL and enhances sialylation of paragloboside in F9 cells with down-regulation of Fut9 expression.

Neuroblastoma cells can be classified according to glycosphingolipid expression profiles identified by liquid chromatography-tandem mass spectrometry.

It is hoped that the gangliosides contained in neuroblastomas (NBs) can be used as outcome predictors. We used liquid chromatography-tandem mass spectrometry (LC-MS) to analyze the gangliosides expressed in 11 NB cell lines. LC-MS analysis detected a number of gangliosides, including acetylated forms, with significantly higher sensitivity than conventional high-performance thin-layer chromatography analysis, and the results revealed that the expression profiles of the gangliosides GD1a, GD2, and acetylated GD2 differed according to the NB cell line. Hierarchical clustering based on the ganglioside expression profiles obtained by LC-MS analysis revealed that the NB cell lines could be classified into three types according to their expression of these three gangliosides: A-type characterized by high expression of GD1a and low or no expression of GD2/acetylated GD2, B-type characterized by low or no expression of GD1a and high expression of GD2/acetylated GD2, and AB-type characterized by expression of both GD1a and GD2/acetylated GD2. Interestingly, all three MYCN non-amplified cell lines were classified into the A-type. The classification was found to be correlated with mRNA expression of ganglioside synthase and neural-differentiation-related genes. The results of this study indicate that LC-MS analysis is useful as a tool for glycosphingolipid research on malignancies.