Honokiol (HK), a well-tolerated natural product, has many multiple pharmacological activities. However, its poor water solubility and low bioavailability limit its clinical application and development. The aim of this research was to prepare the solid dispersion (SD) formulation of honokiol (HK) with poloxamer-188 (PLX) as the carrier, thereby improving its solubility and oral bioavailability. Firstly, by investigating the relationship between the addition amount of the PLX and the solubility of HK, and the effects of solid dispersions with different ratios of HK–PLX on the solubility of HK, we determined that the optimum ratio of PLX to HK was (1:4). Then, the HK–PLX (1:4) SD of HK was prepared using the solvent evaporation method. The morphology of the obtained HK–PLX (1:4) SD was different from that of free HK. The HK in the HK–PLX (1:4) SD existed in amorphous form and formed intermolecular hydrogen bonds with PLX. Additionally, the solubility values of the HK–PLX (1:4) SD were about 32.43 ± 0.36 mg/mL and 34.41 ± 0.38 mg/mL in artificial gastric juice (AGJ) and in artificial intestinal juice (AIJ), respectively. Compared with free HK, the release rate and the bioavailability was also substantially improved for HK in its SD form. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that the HK–PLX (1:4) SD showed higher inhibition of HepG2 cells than free HK. Taken together, the present study suggests that the HK–PLX (1:4) SD could become a new oral drug formulation with high bioavailability and could produce a better response for clinical applications of HK.

Paclitaxel (PTX) is a poor water-soluble antineoplastic drug with significant antitumor activity. However, its low bioavailability is a major obstacle for its biomedical applications. Thus, this experiment is designed to prepare PTX crystal powders through an antisolvent precipitation process using 1-hexyl-3-methylimidazolium bromide (HMImBr) as solvent and water as an antisolvent. The factors influencing saturation solubility of PTX crystal powders in water in water were optimized using a single-factor design. The optimum conditions for the antisolvent precipitation process were as follows: 50 mg/mL concentration of the PTX solution, 25 °C temperature, and 1:7 solvent-to-antisolvent ratio. The PTX crystal powders were characterized via scanning electron microscopy, Fourier transform infrared spectroscopy, high-performance liquid chromatography–mass spectrometry, X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy, solid-state nuclear magnetic resonance, and dissolution and oral bioavailability studies. Results showed that the chemical structure of PTX crystal powders were unchanged; however, precipitation of the crystalline structure changed. The dissolution test showed that the dissolution rate and solubility of PTX crystal powders were nearly 3.21-folds higher compared to raw PTX in water, and 1.27 times higher in artificial gastric juice. Meanwhile, the bioavailability of PTX crystal increased 10.88 times than raw PTX. These results suggested that PTX crystal powders might have potential value to become a new oral PTX formulation with high bioavailability.