Laser Tablet Drilling
Laser drilling is now well established as an economically viable method for producing sub-millimeter holes in pharmaceutical tablets. The benefits of sophisticated drug delivery systems are well proven, including decreased dosing frequency, more consistent drug concentration in the blood, and even customized delivery profiles. Osmotic drug delivery systems have proven especially valuable for providing controlled release of medications. For the manufacturer, laser tablet drilling provides a high speed, highly accurate system that is largely self-operating, able to distinguish “out of spec” holes even at speeds exceeding 140,000 tablets per hour. Inline visual inspection is able to identify and remove “non-passing” tablets from the system without stopping or slowing the drilling process. The typical orifice size in osmotic pump tablets ranges from about 600 μm to 1 mm. A nominal 600 μm hole usually has a ±100 μm tolerance on diameter, and an allowable ellipticity of 1.0 to 1.5. Holes of these dimensions and tolerances could certainly be produced by purely mechanical means; however, no mechanical method has proven capable of working at throughput rates that are consistent with other stages of the pharmaceutical manufacturing process. In contrast, laser tablet drilling, with throughput rates reaching 140,000 tablets/hour, can easily produce holes with the necessary dimensional tolerances and cosmetic appearance. As a result, laser drilling has become the technology of choice for this type of production.