title: Time-resolved near-infrared spectroscopic study of the dissolution of crystalline lactose.
abstract: In the present study, initial dissolution of crystalline α-lactose monohydrate was investigated via time-resolved Fourier Transform near-infrared (FT-NIR) spectroscopy using the liquid penetration method. The process of water penetration is classically characterized by a two-step increment in the combination bands between OH stretching and bending modes of water; however, only one-step increment in the combination bands was induced by penetration of lactose saturated solution. These results suggest that a first phase occurs in which penetrating water adsorbs to solid lactose surface creating a saturated layer, followed by a second phase of dissolution of the hydrated lactose. Decomposition of differential spectra at 2-min intervals supports the existence of an adsorption-diffusion model and gives a threshold as the amount of adsorbed water to dissolve solid lactose.
authors.affiliation: Research Institute of Pharmaceutical Sciences, Faculty of Pharmacy, Musashino University, Tokyo, Japan. yhattori@musashino-u.ac.jp
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Hattori
authors.forename: Makoto
authors.initials: M
authors.lastname: Otsuka
mesh_terms: D000327:Adsorption; D003460:Crystallization; D007785:Lactose / Q000737:chemistry*; D012995:Solubility; D019265:Spectroscopy, Near-Infrared / Q000379:methods; D013607:Tablets; D014867:Water / Q000737:chemistry
chemical_list: D013607:Tablets; D014867:Water; D007785:Lactose