title: Use of near-infrared spectrometry for quantitative determinations of selamectin and moisture in topical formulations.
abstract: A rapid near-infrared spectrometric (NIR) method was qualified for use with the quantitative analysis of selamectin and moisture in topical formulations. Selamectin is currently marketed as a pet endectocide and is available in several formulations for cats and dogs. The use of NIR in this investigation replaces the in-process testing by liquid chromatography and concurrently provided moisture content that would otherwise only be available with additional Karl Fischer titration investigations. A seven-factor partial least square regression (PLS) of the second derivative spectra encompassing the wavelength region of 1450-2200 nm was used to quantify both selamectin and moisture content. A second three-factor PLS solely for water content was also applied and compared with the full model. This qualification confirms that this method may be used to quantitate selamectin and moisture as a process tool or to examine finished good samples. Each sample can be rapidly analyzed within 5 min on the current bench top system.
authors.affiliation: Quality Operations, Pfizer Global Manufacturing, One Pfizer Way, Lee's Summit, MO 64081, USA. greg.webster@pfizer.com
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Webster
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Farrand
authors.forename: Erin
authors.initials: E
authors.lastname: Johnson
authors.forename: Mark A
authors.initials: MA
authors.lastname: Litchman
authors.forename: Neville
authors.initials: N
authors.lastname: Broad
authors.forename: Simon
authors.initials: S
authors.lastname: Maris
mesh_terms: D000977:Antiparasitic Agents / Q000032:analysis*; D002138:Calibration; D002853:Chromatography, Liquid; D006813:Humidity; D007559:Ivermectin / Q000031:analogs & derivatives* / Q000032:analysis*; D016018:Least-Squares Analysis; D009824:Ointments; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D019265:Spectroscopy, Near-Infrared
chemical_list: D000977:Antiparasitic Agents; D009824:Ointments; D007559:Ivermectin; C414354:selamectin