Manufacturing Department Misato Plant, Eisai Co., Ltd., Misato, Kodama, Saitama, Japan.
Drug Dev Ind Pharm. 2012 Mar;38(3):351-6. doi: 10.3109/03639045.2011.604329. Epub 2011 Nov 3.
The purpose of this study was to examine application of ultraviolet (UV) laser irradiation to printing soft gelatin capsules containing titanium dioxide (TiO(2)) in the shells and to study effect of UV laser power on the color strength of printing on the soft gelatin capsules.
Size 6 Oval type soft gelatin capsules of which shells contained 0.685% TiO(2) and 0.005% ferric dioxide were used in this study. The capsules were irradiated pulsed UV laser at a wavelength 355 nm. The color strength of the printed capsules was determined by a spectrophotometer as total color difference (dE).
The soft gelatin capsules which contained TiO(2) in the shells could be printed gray by the laser. Many black particles, which were associated with the printing, were formed at the colored parts of the shells. It was found that there were two inflection points in relationship between output laser energy of a pulse and dE. Below the lower point, the capsules were not printed. From the lower point to the upper point, the capsules were printed gray and total color difference of the printing increased linearly in proportion with the output laser energy. Beyond the upper point, total color difference showed saturation because of micro-bubbles formation at the laser irradiated spot.
Soft gelatin capsules containing TiO(2) in the shells could be performed stable printing using the UV laser printing technique. Color strength of the printing could be controlled by regulating the laser energy between the two inflection points.
本研究旨在考察紫外（UV）激光辐射在含有二氧化钛（TiO₂）的软明胶胶囊壳上印刷的应用，并研究 UV 激光功率对软明胶胶囊印刷颜色强度的影响。
本研究使用了 6 号椭圆形软明胶胶囊，其壳中含有 0.685%的 TiO₂和 0.005%的氧化铁。胶囊采用波长为 355nm 的脉冲紫外激光进行辐照。使用分光光度计测定打印胶囊的颜色强度，以总色差（dE）表示。
含有 TiO₂的壳的软明胶胶囊可以用激光打印成灰色。在壳的彩色部分形成了许多与打印相关的黑色颗粒。结果发现，脉冲输出激光能量与 dE 之间存在两个转折点。在较低点以下，胶囊无法打印。从较低点到较高点，胶囊被打印成灰色，打印的总色差与输出激光能量成线性比例增加。超过较高点后，由于激光照射点形成微气泡，总色差呈现饱和。
含有 TiO₂的壳的软明胶胶囊可以使用紫外激光打印技术进行稳定的打印。通过在两个转折点之间调节激光能量，可以控制打印的颜色强度。
