Crystallization of Polymorphic Sulfathiazole Controlled by Femtosecond Laser-Induced Cavitation Bubbles
Jiachen Yu, Jianfeng Yan, Lan Jiang
Abstract
Crystals have been widely used in the pharmaceutical industry, structural elucidation, and other biomedical fields. Different polymorphs of one compound possess distinct physical and chemical properties. Some polymorphs are more favorable in applications such as drug delivery and structural characterization. However, owing to the complex mechanisms of the crystallization process, controlling the crystallization result is still difficult. In this study, we found that the femtosecond laser could be applied to control the crystallization of sulfathiazole. By introducing femtosecond laser irradiation, the crystal number and proportion of specific polymorphs were promoted. The interaction of the femtosecond laser with the solution was studied by time-resolved optical microscopy at a time scale of 200 fs to 50 μs. It is suggested that laser-induced cavitation bubbles act as nucleation centers in the crystallization process. Applying ultrasound to tune the bubble dynamics also has impact on the crystallization results. The control of the nucleation results was achieved through femtosecond laser-induced bubble generation. These results offer an approach for controlling the crystallization of sulfathiazole and also provide some knowledge on the process of laser-induced nucleation.