title: The compressibility and compactibility of different types of lactose.
abstract: OBJECTIVE
  The purpose of this study was to investigate and quantify flow properties, compressibility, and compactibility of various pharmaceutical lactose powders found on the market today (DCL-11, DCL-21, M-200, Flowlac-100, and Tablettose 70, 80, and 100).
  
  
  METHODS
  Flow properties were estimated by measuring flow time, angle of repose, and the Hausner ratio. Particle rearrangement was studied using Kawakita's linear model. Compressibility was studied using two 'out-of-die' methods: (i) the Heckel model and (ii) a modified Walker model. Compactibility was quantified using two methods: (i) the tensile strength profile (Cp) and (ii) the compactibility factor (Pr). Statistical approach was used to analyze the results.
  
  
  RESULTS
  Flow properties of all materials were passable or better, except for M-200, which has very poor flowability. Compressibility results demonstrated that the most compressible lactose is spray-dried grade of lactose (Flowlac-100) and the least compressible is milled lactose (M-200). Compactibility studies showed that beta-lactose (DCL-21) forms tablets with superior tensile strength in comparison with alpha-lactose.
  
  
  CONCLUSIONS
  Results of the compressibility study showed that the discriminative power of modified Walker model is greater in comparison with Heckel model. Compactibility methods yield similar and comparable results.
authors.affiliation: Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia.
authors.forename: Ilija
authors.initials: I
authors.lastname: Ilić
authors.forename: Peter
authors.initials: P
authors.lastname: Kása
authors.forename: Rok
authors.initials: R
authors.lastname: Dreu
authors.forename: Klara
authors.initials: K
authors.lastname: Pintye-Hódi
authors.forename: Stane
authors.initials: S
authors.lastname: Srcic
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods; D005079:Excipients / Q000737:chemistry*; D007785:Lactose / Q000737:chemistry*; D008962:Models, Theoretical; D011208:Powders; D013607:Tablets; D013718:Tensile Strength
chemical_list: D005079:Excipients; D011208:Powders; D013607:Tablets; D007785:Lactose