title: Drug tablet thickness estimations using air-coupled acoustics.
abstract: A non-contact/non-destructive acoustic technique for predicting the coating layer thickness of a drug tablet is presented. Quality of tablet coatings can play a major role in the effectiveness of drug delivery. Many pharmaceutical tablets consist of a tablet core and a coated outer cover. Variations in the tablet coating can be indicative of various process problems and, therefore, is of a concern for quality assurance. In the current non-contact measurement system, an air-coupled excitation and laser interferometric detection for predicting the coating layer thickness of a drug tablet is introduced. Drug tablets with different coating thicknesses are vibrated via an acoustic field generated by an air-coupled transducer in a frequency range sufficiently high to excite their several vibrational modes. The tablet surface vibrational responses are acquired at a number of measurement points by a laser interferometer in a non-contact manner. An iterative computational procedure, based on the FE method and Newton's method, was developed and demonstrated to extract the coating layer thicknesses of the tablets from a subset of the measured resonance frequencies.
authors.affiliation: Department of Mechanical and Aeronautical Engineering, Center for Advanced Materials Processing, Wallace H. Coulter School of Engineering, Clarkson University, Potsdam, NY 13699-5725, USA.
authors.forename: Ilgaz
authors.initials: I
authors.lastname: Akseli
authors.forename: Cetin
authors.initials: C
authors.lastname: Cetinkaya
mesh_terms: D000162:Acoustics; D000465:Algorithms; D002626:Chemistry, Pharmaceutical; D003198:Computer Simulation; D020342:Finite Element Analysis; D005544:Forecasting; D007368:Interferometry / Q000379:methods; D007834:Lasers; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011786:Quality Control; D013607:Tablets / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*; D014732:Vibration
chemical_list: D004364:Pharmaceutical Preparations; D013607:Tablets