An HPLC-UV method has been developed for the determination of valibose, miglitol, voglibose and acarbose, the four anti-diabetic drugs. The separation was accomplished successfully by using reversed phase chromatography (Prevail carbohydrate column, 250 mm x 4.6 mm, 5 microm) with a gradient acetonitrile-phosphate buffer solution (pH 8.0) at a wavelength of 210 nm. Furthermore, the method of a high-performance liquid chromatography coupled with ESI-MS in positive ionization mode has been established. These two methods were successfully applied to the assay and qualitative detection of four alpha-glucosidase inhibitors in the potential counterfeit anti-diabetic drugs.
1-Deoxynojirimycin ; analogs & derivatives ; analysis ; Acarbose ; analysis ; Chromatography, High Pressure Liquid ; methods ; Chromatography, Reverse-Phase ; Glycoside Hydrolase Inhibitors ; Hypoglycemic Agents ; chemistry ; Inositol ; analogs & derivatives ; analysis ; Spectrometry, Mass, Electrospray Ionization ; methods ; Spectrophotometry, Ultraviolet ; alpha-Glucosidases ; analysis

Fabry disease is an X-linked inborn error of glycosphingolipid catabolism that results from mutations in the gene encoding the alpha-galactosidase A (GLA) enzyme. We have identified 15 distinct mutations in the GLA gene in 13 unrelated patients with classic Fabry disease and 2 unrelated patients with atypical Fabry disease. Two of the identified mutations were novel (i.e., the D231G missense mutation and the L268delfsX1 deletion mutation). This study evaluated the effects of the chemical chaperones 1-deoxygalactonojirimycin (DGJ) on the function of GLA in vitro, in cells containing missense mutations in the GLA gene. Nine missense and a nonsense mutations, including one novel mutation were cloned into mammalian expression vectors. After transient expression in COS-7 cells, GLA enzyme activity and protein expression were analyzed using fluorescence spectrophotometry and Western blot analysis, respectively. DGJ enhanced GLA enzyme activity in the M42V, I91T, R112C and F113L mutants. Interestingly, the I91T and F113L mutations are associated with the atypical form of Fabry disease. However, DGJ treatment did not have any significant effect on the GLA enzyme activity and protein expression of other mutants, including C142W, D231G, D266N, and S297F. Of note, GLA enzyme activity was not detected in the novel mutant (i.e., D231G), although protein expression was similar to the wild type. In the absence of DGJ, the E66Q mutant had wild-type levels of GLA protein expression and approximately 40% GLA activity, indicating that E66Q is either a mild mutation or a functional single nucleotide polymorphism (SNP). Thus, the results of this study suggest that the chemical chaperone DGJ enhances GLA enzyme activity and protein expression in milder mutations associated with the atypical form of Fabry disease.
1-Deoxynojirimycin/*analogs & derivatives/metabolism ; Adolescent ; Adult ; Animals ; Asian Continental Ancestry Group/*genetics ; COS Cells ; Cercopithecus aethiops ; Fabry Disease/*enzymology/genetics ; Gene Expression ; Humans ; Male ; Middle Aged ; Mutation ; Young Adult ; alpha-Galactosidase/*genetics/*metabolism