title: The effect of relative humidity on the physical properties of two melibiose monohydrate batches with differing particle size distributions and surface properties.
abstract: Melibiose monohydrate has shown promise when employed as a pharmaceutical excipient, but its physical properties have not been adequately characterized. Therefore, two different melibiose monohydrate batches were analyzed as received or after storage under different relative humidity (RH) atmospheres. The particle size distributions and specific surface areas of the two batches were shown to differ considerably, which also had an effect on their water sorption tendencies and on the intermolecular structure of melibiose after storage. The relatively large primary particles that were more abundant in one of the batches were shown to possess a porous surface structure, and water evaporation from them occurred in two phases when heated. Furthermore, storing the batch with smaller mean particle size under dry conditions affected the crystal structure and molecular vibrations of the sample more than in the case of the batch with larger mean particle size. It was concluded that the physical properties of melibiose monohydrate after storage at different RH atmospheres is largely governed by the primary particle size and porosity.
authors.affiliation: University of Helsinki, Helsinki, Finland. petteri.heljo@helsinki.fi
authors.forename: Ville P
authors.initials: VP
authors.lastname: Heljo
authors.forename: Janne
authors.initials: J
authors.lastname: Sainio
authors.forename: Anna
authors.initials: A
authors.lastname: Shevchenko
authors.forename: Niina
authors.initials: N
authors.lastname: Kivikero
authors.forename: Satu
authors.initials: S
authors.lastname: Lakio
authors.forename: Anne M
authors.initials: AM
authors.lastname: Juppo
mesh_terms: D002626:Chemistry, Pharmaceutical; D003460:Crystallization; D018360:Crystallography, X-Ray; D004356:Drug Storage; D005079:Excipients / Q000737:chemistry*; D006813:Humidity; D008553:Melibiose / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D010316:Particle Size; D016062:Porosity; D033362:Powder Diffraction; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013678:Technology, Pharmaceutical / Q000379:methods; D044366:Transition Temperature; D014867:Water / Q000737:chemistry*; D017155:Wettability
chemical_list: D005079:Excipients; D014867:Water; D008553:Melibiose