A novel capillary electrophoresis (CE) method with contactless conductivity detection suitable for the determination of glucosamine (GlAm) and K+ in pharmaceuticals was devised. Under the optimum conditions (aqueous 30 mM acetate buffer of pH 5.2 as the background electrolyte; voltage 30 kV; 25 degrees C), GlAm (migrating as glucosaminium cation) was well separated from K+ that could occur in the dosage forms as excipient. The CE analysis was performed in fused-silica capillaries (50 mu m i.d., 75 cm total length, 27 cm to detector) and the separation took < 3 min. The calibration graphs were linear for both GlAm (100-300 mu g/mL; r(2) = 0.997) and K+ (15-75 mu g/mL; r(2) = 0.997) when using ethanolamine (100 mu g/mL) as the internal standard. The LOD values (S/N = 3) were 9.3 mu g/mL for GlArn and 2.9 mu g/mL for K+. The method was applied to the assay of GlAm content in various dosage forms. Intermediate precision evaluated by determining the content of GlAm in a single formulation on 3 consecutive days was characterized by RSD 2.35% (n = 15). Acceptable accuracy of the CE method was confirmed by the added/found GlAm recovery experiments (recoveries 94.6-103.3%) and by statistical comparison of the results attained by the proposed CE and a reference HPLC method.