title: Reduction of melting temperature and enthalpy of drug crystals: theoretical aspects.
abstract: This review deals with the mathematical models describing the reduction of melting temperature and enthalpy of solids in the nano-size range. In particular, the attention focuses on the thermodynamic based models that are theoretically solid and can be suitably used in the case of organic drugs. Indeed, while much effort has been put in the past to study the melting of metal nano-crystals, little work has been done for organic drug nano-crystals. However, due to the high potential of drug nano-crystals (their solubility increases with size reduction), this theme has become more and more important in the pharmaceutical field. Accordingly, this review, after illustrating the physical frame of drug melting, focuses on the thermodynamic aspects required to describe the melting of spherical and not spherical nano-crystals. Finally, the reliability of some models is tested against the results coming from X-rays analysis in the case of two organic drugs (griseofulvin and nifedipine). This test proved models strength.
authors.affiliation: Dept. of Chemical and Pharmaceutical Sciences, Trieste University, Piazzale Europa 1, Trieste I-34127, Italy.
authors.forename: Dritan
authors.initials: D
authors.lastname: Hasa
authors.forename: Dario
authors.initials: D
authors.lastname: Voinovich
authors.forename: Beatrice
authors.initials: B
authors.lastname: Perissutti
authors.forename: Gabriele
authors.initials: G
authors.lastname: Grassi
authors.forename: Simona
authors.initials: S
authors.lastname: Fiorentino
authors.forename: Rossella
authors.initials: R
authors.lastname: Farra
authors.forename: Michela
authors.initials: M
authors.lastname: Abrami
authors.forename: Italo
authors.initials: I
authors.lastname: Colombo
authors.forename: Mario
authors.initials: M
authors.lastname: Grassi
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D006118:Griseofulvin / Q000737:chemistry; D008962:Models, Theoretical; D053758:Nanoparticles / Q000737:chemistry*; D009543:Nifedipine / Q000737:chemistry; D009930:Organic Chemicals / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D044367:Phase Transition; D012995:Solubility; D013816:Thermodynamics; D044366:Transition Temperature
chemical_list: D009930:Organic Chemicals; D004364:Pharmaceutical Preparations; D006118:Griseofulvin; D009543:Nifedipine
keywords: Drug; Enthalpy; Mathematical model; Melting; Nano-crystal