RT Journal Article SR Electronic T1 Simple HPLC Determination of Benzalkonium Chloride in Ophthalmic Formulations Containing Antazoline and Tetrahydrozoline JF PDA Journal of Pharmaceutical Science and Technology JO PDA J Pharm Sci Technol FD Parenteral Drug Association (PDA) SP 332 OP 337 VO 59 IS 5 A1 Rojsitthisak, Pornchai A1 Wichitnithad, Wisut A1 Pipitharome, Ongart A1 Sanphanya, Kingkan A1 Thanawattanawanich, Peeracha YR 2005 UL http://journal.pda.org/content/59/5/332.abstract AB A simple and rapid analytical procedure for routine quantification of n-C12H25 and n-C14H29 benzalkonium chloride (C-12 and C-14 BKC) homologs in ophthalmic formulations containing antazoline HCl and tetrahydrozoline HCl by high-performance liquid chromatography was developed and validated. The ophthalmic solution samples can be directly analyzed by reversed-phase on HiQ-Sil C18 column (4.6 mm × 150 mm, i.d., 5-μm particle size) with acetonitrile–sodium acetate buffer (pH 5.0; 0.2 M) (70:30, v/v) as mobile phase. UV Detection was carried out at 262 nm. The method was linear over the selected concentration and ranged from 0.03 to 0.10 mg/ml (r2 = 0.9999) and from 0.01 to 0.05 mg/ml (r2 = 0.9979) for C-12 and C-14 BKC homologs, respectively. The mean percent recoveries were 100.2 and 102.6 and the percent CV values were 1.3 and 3.5 for C-12 and C-14 BKC homologs, respectively. The results demonstrated the good linearity, accuracy, and precision. The method was applied to determine two commercial ophthalmic formulations, and the percent label amounts of total BKC contents were found to be 99.7 and 103.2.