title: Air-coupled non-contact mechanical property determination of drug tablets.
abstract: A non-contact/non-destructive technique for determining the mechanical properties of coated drug tablets is presented. In the current measurement approach, air-coupled excitation and laser interferometric detection are utilized and their effectiveness in characterizing the mechanical properties of a drug tablet by examining its vibrational resonance frequencies is demonstrated. The drug tablet is vibrated via an acoustic field of an air-coupled transducer in a frequency range sufficiently high to excite its several vibrational modes (harmonics). The tablet surface vibrational responses at measurement points are acquired by a laser vibrometer in a non-contact manner. An iterative computational procedure based on the finite element method is developed to extract the mechanical properties of the coated tablet from a subset of its measured resonance frequencies. The mechanical properties measured by this technique are compared to those obtained by a standard contact ultrasonic measurement method and a good agreement is found. Sensitivities of the resonance frequencies to the changes in the tablet mechanical properties are also obtained and discussed. The presented non-destructive technique requires no physical contact with the tablet and operates in the microsecond time-scale. Therefore, it could be employed for rapid monitoring and characterization applications.
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; D002626:Chemistry, Pharmaceutical; D020342:Finite Element Analysis; D007368:Interferometry / Q000379:methods; D007834:Lasers; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D013607:Tablets / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*; D014465:Ultrasonics; D014732:Vibration
chemical_list: D004364:Pharmaceutical Preparations; D013607:Tablets