Department of Mechanical and Aeronautical Engineering, Photo-Acoustic Research Laboratory, Clarkson University, Potsdam, New York 13699-5725, USA.
AAPS PharmSciTech. 2010 Mar;11(1):90-102. doi: 10.1208/s12249-009-9352-9. Epub 2010 Jan 9.
A noncontact/nondestructive air-coupled acoustic technique to be potentially used in mechanical property determination of bilayer tablets is presented. In the reported experiments, a bilayer tablet is vibrated via an acoustic field of an air-coupled transducer in a frequency range sufficiently high to excite several vibrational modes (harmonics) of the tablet. The tablet vibrational transient responses at a number of measurement points on the tablet are acquired by a laser vibrometer in a noncontact manner. An iterative computational procedure based on the finite element method is utilized to extract the Young's modulus, the Poisson's ratio, and the mass density values of each layer material of a bilayer tablet from a subset of the measured resonance frequencies. For verification purposes, a contact ultrasonic technique based on the time-of-flight data of the longitudinal (pressure) and transverse (shear) acoustic waves in each layer of a bilayer tablet is also utilized. The extracted mechanical properties from the air-coupled acoustic data agree well with those determined from the contact ultrasonic measurements. The mechanical properties of solid oral dosage forms have been shown to impact its mechanical integrity, disintegration profile and the release rate of the drug in the digestive tract, thus potentially affecting its therapeutic response. The presented nondestructive technique provides greater insight into the mechanical properties of the bilayer tablets and has the potential to identify quality and performance problems related to the mechanical properties of the bilayer tablets early on the production process and, consequently, reduce associated cost and material waste.
一种潜在应用于双层片剂机械性能测定的非接触式、无损空气耦合声技术被提出。在报道的实验中，双层片剂通过空气耦合换能器的声场在足够高的频率范围内振动，以激发片剂的多个振动模式（谐频）。通过激光测振仪以非接触方式在片剂上的多个测量点获取片剂的振动瞬态响应。基于有限元方法的迭代计算程序用于从测量的共振频率子集提取双层片剂各层材料的杨氏模量、泊松比和质量密度值。为了验证目的，还利用基于双层片剂各层中纵波（压力）和横波（剪切）声波的飞行时间数据的接触式超声技术。从空气耦合声数据中提取的机械性能与从接触式超声测量确定的机械性能吻合良好。固体口服剂型的机械性能已被证明会影响其机械完整性、崩解特性和在消化道中的药物释放率，从而可能影响其治疗反应。所提出的无损技术提供了对双层片剂机械性能的更深入了解，并有可能在生产过程早期识别与双层片剂机械性能相关的质量和性能问题，从而降低相关成本和材料浪费。
