Table 2.

Intracellular uptake of enisamium in different host cell systems.

Cell system	Concentration of enisamium (mean ± SD, ng/106 cells)a		Permeability(mean ± SD, %)b
	Initial input	Intracellular
MDCK cells	35,300 ± 1700	27.9 ± 1.4	0.08 ± 0.01
Undifferentiated NHBE cells	487,000 ± 2200	4110 ± 830	0.85 ± 0.21
Differentiated NHBE cells	568,000 ± 42,000	10,700 ± 1900	1.90 ± 0.20

MDCK: Madin–Darby canine kidney; NHBE: normal human bronchial epithelial.

^aThe cells were overlaid with medium containing enisamium (100 µM of enisamium iodide for MDCK cells and 2000 µM of enisamium chloride for undifferentiated and dNHBE cells) and incubated at 37°C under 5% CO₂ for 24 h (n = 3 wells). The cellular lysates and supernatants were harvested and the concentration of enisamium was determined using LC–MS/MS. Concentration is expressed as nanograms (ng) per 10⁶ cells.

^bPermeability of enisamium was calculated as the ratio of the intracellular concentration to that in the initial drug input, and expressed as percentage.