Analysis of polyhexamethylene biguanide and alexidine in contact lens solutions using capillary electrophoresis, ultra-performance liquid chromatography and quadrupole time of flight mass spectrometry

Poly(hexamethylene biguanide) hydrochloride (PHMB)-based materials: synthesis, modification, properties, determination, and application

“…A variety of analytical methods have been developed for the quantitation of PHMB in various samples, e.g., spectrophotometry, capillary electrophoresis, colorimetric method, liquid chromatography, mass spectrometry, and titrimetric method. 50,[76][77][78][79] UV-vis spectrophotometry provides a simple and fast way to quantify PHMB in aqueous solutions based on the established calibration curve according to the maximum adsorption wavelength (approx. 235 nm).…”

“…Considering the polydispersity nature of PHMB, Thompson and coworkers reported a more sensitive and reliable analytical method, ultra-performance liquid chromatography (UPLC), for the quantitative measurement of PHMB in commercial contact lens solutions with a much lower LOD (Table 3). 79 The cationic nature of biguanide moieties enables PHMB to stoichiometrically react with polyanions to form complexes, which lays a foundation for titrimetry to quantify PHMB. 82 Two salient points involved in titrimetry require special attention, i.e., recognizing the titration end point and measuring…”

“…Considering the polydispersity nature of PHMB, Thompson and coworkers reported a more sensitive and reliable analytical method, ultra-performance liquid chromatography (UPLC), for the quantitative measurement of PHMB in commercial contact lens solutions with a much lower LOD (Table 3). 79…”