Innovative Use of Medical Infrared Thermography to Evaluate Adhesive Properties of Two Buprenorphine Transdermal Patch Formulations in a Single Dose Adhesion Performance Study

An innovative approach for the assessment of transdermal patches adherence to the skin was developed and applied post-hoc to supportive imaging data collected in an open label, two-period, two-sequence, two-way crossover, controlled, randomized, single dose study to assess adhesion performance of two buprenorphine formulations (generic versus originator), applied topically to healthy male and female volunteers. The technology used for data acquisition is called Medical Infrared Thermography (MIT), a non-invasive, non-radiating imaging technique for surface temperature mapping. The use of this technology in an adhesion performance study was based on the rationale that the surface of a transdermal patch reaches a temperature in equilibrium with that of the body area where it is applied and whenever a discontinuity between skin and patch exists, the transmission of thermic energy to the surface of the transdermal patch changes. In case air is interposed, the transmission is minimal so any cases of patch lift-off from skin become visible on thermograms. The thermograms were acquired in standardized conditions but were initially intended only as supportive imaging technique, while the primary adhesion performance data was acquired through the standard approach of visual examination coupled with manual markings. In this article we further demonstrate the value of the acquired thermograms as main adhesion assessment tools, used in conjuncture with an in-house validated image processing software for the actual quantification of percentages of detachment. This novel approach for automated and unbiased analysis of adhesion performance was shown to be highly reliable and reproducible, attributes that recommend it for future use as primary adhesion assessment tool pending completion of full method validation.