Air-coupled non-contact mechanical property determination of drug tablets

Int J Pharm. 2008 Jul 9;359(1-2):25-34. doi: 10.1016/j.ijpharm.2008.03.020. Epub 2008 Mar 22.

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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acoustics*
  • Chemistry, Pharmaceutical
  • Finite Element Analysis
  • Interferometry / methods
  • Lasers
  • Pharmaceutical Preparations / chemistry*
  • Tablets / chemistry
  • Technology, Pharmaceutical / methods*
  • Ultrasonics
  • Vibration

Substances

  • Pharmaceutical Preparations
  • Tablets