Effectiveness of ophthalmic solution preservatives: a comparison of latanoprost with 0.02% benzalkonium chloride and travoprost with the sofZia preservative system

Table 3 Microbial reduction (log₁₀ CFU/mL) by time point

Sample	Microorganism	Inoculum	0 hours	6 hours	24 hours	7 days	14 days	28 days
Latanoprost 0.005% (Lot No: LA54019)	S. aureus	5.8	> 4.8	> 4.8	> 4.8	> 4.8	> 4.8	> 4.8
	P. aeruginosa	5.7	4.7	> 4.7	> 4.7	> 4.7	> 4.7	> 4.7
	E. coli	6.0	> 5.0	> 5.0	> 5.0	> 5.0	> 5.0	> 5.0
	C. albicans	5.7	0.9	> 4.7	> 4.7	> 4.7	> 4.7	> 4.7
	A. brasiliensis	5.4	0.1	> 4.4	> 4.7	> 4.4	> 4.4	> 4.4
Travoprost 0.004% (Lot No: 158568F)	S. aureus	5.8	0	0.1	0.2	> 4.8	> 4.8	> 4.8
	P. aeruginosa	5.7	0.1	0.8	1.7	> 4.7	> 4.7	> 4.7
	E. coli	6.0	0.3	1.5	2.8	> 5.0	> 5.0	> 5.0
	C. albicans	5.7	0.1	0.2	0.1	0.6	1.0	1.8
	A. brasiliensis	5.4	0.1	0.2	0.9	1.7	1.9	1.8

CFU: colony-forming unit.
Latanoprost ophthalmic solution 0.005% contains 0.02% benzalkonium chloride and travoprost ophthalmic solution 0.004% contains sofZia as preservatives.
Shading indicates results not meeting European Pharmacopoeia-A (EP-A) requirements [11] (note that while testing of E. coli is required only for non-oral products in the EP, this would be considered a failing result).

ISSN: 1471-2415