Danshensu [3-(3, 4-dihydroxyphenyl) lactic acid, DSS], one of the significant cardioprotective components, is extracted from the root of Salvia miltiorrhiza. In the present study, an ester prodrug of Danshensu (DSS), palmitoyl Danshensu (PDSS), was synthesized with the aim to improve its oral bioavailability and prolong its half-life. The in vitro experiments were carried out to evaluate the physicochemical properties and stability of PDSS. Although the solubility of PDSS in water was only 0.055 mg·mL−1, its solubility in FaSSIF and FeSSIF reached 4.68 and 9.08 mg·mL−1, respectively. Octanol-water partition coefficient (log P) was increased from −2.48 of DSS to 1.90 of PDSS. PDSS was relatively stable in the aqueous solution in pH range from 5.6 to 7.4. Furthermore, the pharmacokinetics in rats was evaluated after oral administration of PDSS and DSS. AUC and t1/2 of PDSS were enhanced up to 9.8-fold and 2.2-fold, respectively, compared to that of DSS. Cmax was 1.67 ± 0.11 μg·mL−1 for PDSS and 0.81 ± 0.06 μg·mL−1 for DSS. Thus, these results demonstrated that PDSS had much higher oral bioavailability and longer circulation time than its parent drug.

Catalase is a promising therapeutic enzyme; however, it carries risks of inactivation and rapid degradation when it is used in practical bioprocess, such as delivery in vivo. To overcome the issue, we made catalase-only nanoparticles using shear stress alone at a moderate shear rate of 217 s−1 in a coaxial cylinder flow cell. Properties of nanoparticles, including particle size, polydispersity index and zeta potential, were characterized. The conformational changes of pre- and post-sheared catalase were determined using spectroscopy techniques. The results indicated that the conformational changes of catalase and reduction in α-helical content caused by shear alone were less significant than that by desolvation method. Catalase-only nanoparticles prepared by single shear retained over 90% of its initial activity when compared with the native catalase. Catalase nanoparticles lost only 20% of the activity when stored in phosphate buffer solution for 72 h at 4 °C, whereas native catalase lost 53% under the same condition. Especially, the activity of nanogranulated catalase was decreased only slightly in the simulated intestinal fluid containing α-chymotrypsin during 4 h incubation at 37 °C, implying that the catalase nanoparticle was more resistant to the degradation of proteases than native catalase molecules. Overall, catalase-only nanoparticles offered a great potential to stabilize enzymes for various pharmaceutical applications.