| 초록 |
The adhesion and friction forces of pharmaceutical materials were quantitatively compared using Atomic Force Microscopy (AFM), and the applicability of the AFM force measurement technique to pharmaceutical research and development was evaluated. A steel sphere was attached to the tip of an AFM cantilever, and its adhesion forces to the substrate surfaces of polyvinyl pyrrolidone, magnesium stearate, sodium stearyl fumarate, lactose, 4-acetamidophenol, and naproxen were measured. Humidity was found to be an important variable. Surface roughness varied by an order of magnitude among the materials. However, results clearly showed that the two lubricants had much lower (ca. 1/2) adhesion force than lactose, 4-acetamidophenol, and naproxen. The two lubricants showed an insignificant difference in their intrinsic adhesion forces. Surface treatment and compaction were able to slightly modify the adhesion force. The tip-to-tip variation of the adhesion force was not greater than the difference between lubricants and other pharmaceutical particles. The contamination of the steel surface by substrate materials in molecular levels is suspected, but found insignificant. Lubricant molecules themselves seem to be unable to cover the surface of other particle surface. |
