Pulmonary response to intratracheal instillation of ultrafine versus fine titanium dioxide: role of particle surface area

Table 1 Potency difference between UFTiO₂ and FTiO₂ when analyzed on a mass vs. surface area basis.

Parameter	Dose Metric	1 Day	7 Days	42 Days
PMN (10⁶)
	Mass	41	41	41
	Surface Area	2	1.3	1.6
LDH (U/l)
	Mass	41	30	41
	Surface Area	1.2	1.2	1.8
Albumin
	Mass	82	41	41
	Surface Area	3	1.4	2
TNF-α (pg/ml)
	Mass	41	41	41
	Surface Area	1.2	1.4	1.5
MIP-2 (pg/ml)
	Mass	41	41	82
	Surface Area	1.2	1.1	1.1
IL-1β (pg/ml)
	Mass	82	82	82
	Surface Area	1.6	1.8	1.4
Zym. Stim. Chemi.
	Mass	82	82	82
	Surface Area	1.75	1.8	3
NO Dep. Chemi.
	Mass	41	82	82
	Surface Area	1.5	7	8

Comparison of UFTiO₂ and FTiO₂ potency differences. The data were analyzed to show the potency difference between UFTiO₂ and FTiO₂ on a mass basis as well as the fold increase in pulmonary toxicity response on a surface area basis. All post-exposure time points were analyzed and are reported in the table. On a mass basis, the UFTiO₂ has much greater potency than FTiO₂, but when dose is normalized to total particle surface area administered the fold increase in response between the UFTiO₂ and FTiO₂ is greatly reduced.

ISSN: 1743-8977