title: Development of a Raman method to follow the evolution of coating thickness of pellets.
abstract: BACKGROUND
  Although several methods have been investigated to measure the film thickness of tablets and its correlation with the dissolution behavior, much fewer such investigations exist for pharmaceutical pellets.
  
  
  OBJECTIVE
  To study the possibility of measuring the film thickness and predicting the dissolution behavior of pellets produced in different fluid bed equipments with Raman spectroscopy.
  
  
  METHODS
  Pyridoxine hydrochloride-layered pellets were produced and coated in two different Strea-1 equipments. Raman spectra were collected and analysed to set up a calibration model based on the film thickness data calculated from Camsizer analysis results. Dissolution tests were done according to Ph. Eur. standards.
  
  
  RESULTS
  Raman spectroscopy proved to be a good tool in the measurement of film thickness. Polymer weight gain showed a linear correlation with film thickness but was a poor predictor of dissolution results below a threshold value.
  
  
  CONCLUSIONS
  The Raman spectroscopic measurement of a small sample can provide accurate data of the film thickness. The investigation suggests that a threshold value might exist for the film thickness above which it can be used to judge future dissolution results.
authors.affiliation: Department of Pharmaceutical Technology, University of Szeged , Szeged , Hungary and.
authors.forename: Krisztina
authors.initials: K
authors.lastname: Nikowitz
authors.forename: Friederike
authors.initials: F
authors.lastname: Folttmann
authors.forename: Markus
authors.initials: M
authors.lastname: Wirges
authors.forename: Klaus
authors.initials: K
authors.lastname: Knop
authors.forename: Klára
authors.initials: K
authors.lastname: Pintye-Hódi
authors.forename: Géza
authors.initials: G
authors.lastname: Regdon
authors.forename: Peter
authors.initials: P
authors.lastname: Kleinebudde
mesh_terms: D002138:Calibration; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004343:Drug Implants / Q000737:chemistry*; D005079:Excipients / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011736:Pyridoxine / Q000737:chemistry; D012995:Solubility; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties; D013607:Tablets / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D004343:Drug Implants; D005079:Excipients; D011108:Polymers; D013607:Tablets; D011736:Pyridoxine
keywords: Chemometric analysis; PCA; PLS; Raman; dissolution; film thickness; pellet