Gas Chromatographic Assessment of Residual Solvents Present in Excipient-Benzyl Alcohol

This article describes a simple and rapid gas chromatographic method for identification of residual solvents present in benzyl alcohol. Benzyl alcohol is used in foods and pharmaceutical products.

The organic solvents such as benzene, chlorobenzene and toluene are frequently used in manufacturing of benzyl alcohol. Even after such manufacturing process, some solvents still remain in small quantities.

Method for the quantification of residual solvents present in benzyl alcohol was done by gas chromatography with flame ionization detector and utilizes the Agilent 7700 with FID (DB-624, 30 m × 0.53 mm, 3 μ) capillary column, nitrogen as carrier gas with a flow rate of 2.5 ml mn-1.

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Features of N-Glycosylation of Immunoglobulins from Knockout Pig Models

For the first time, the N-glycosylation patterns of immunoglobulin G (IgGs) isolated from the serum of two varieties of knockout pigs (lacking N-glycolylneuraminic acid (Neu5Gc) and/or α 1,3 galactose) were examined for the presence of potential glycan xenoantigens and compared to N-glycosylation patterns obtained for wild-type (WT) pig IgGs.

Glycopeptide analysis was chosen over glycan release, as protein-A eluates from pig serum may contain IgA and IgM as shown previously. The experiments focused on the analysis of tryptic glycopeptides EEQFNSTYR and AEQFNSTYR from IgGs, and excluded IgA and IgM, in which N-glycosylated peptides have different sequences and masses. WT pig IgG glycopeptides showed the presence of N-glycolylneuraminic acid (Neu5Gc) and absence of N-acetylneuraminic acid (Neu5Ac). Released glycans from the protein-A eluate, however, showed the presence of both types of sialic acids, allowing Neu5Ac to be attributed to IgA and/or IgM.

The WT IgG samples also showed the presence of glycans that could by composition have been α-galactosylated, but treatments with α- and β-galactosidases produced inconclusive results as to the linkage nature of the terminal Gal residues. Single knockout (α-Gal transferase) pig IgG was shown to contain Neu5Gc residues, and there was a definite absence of α-Gal.