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Naproxen (NAP) is a non-steroidal anti-inflammatory drug (NSAID) that belongs to the arylpropionic acid class. Classified as a Biopharmaceutical Classification System (BCS) class II drug, NAP exhibits low water solubility, thus resulting in restricted oral bioavailability. This study aimed to evaluate the effectiveness of pharmaceutical salts in enhancing the solubility and oral bioavailability of NAP. Two novel NAP salts, specifically naproxen-ethylenediamine (NAP-EDA) and naproxen-trometamol (NAP-TRIS), were synthesized using a 2:1 and 1:1 stoichiometric ratio, respectively. The NAP-EDA and NAP-TRIS powders were thoroughly characterized using single-crystal X-ray diffraction (SXRD), powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC), providing a comprehensive understanding of their structural and thermal properties. Additionally, the solubilities and dissolution rates of NAP-EDA and NAP-TRIS salts were assessed in water and a pH 6.86 phosphate buffer. Notably, the solubility of NAP-TRIS salt increased markedly, by 397.5-fold in water and 6.2-fold at pH 6.86. Furthermore, in vivo pharmacokinetic studies in rats revealed that NAP-TRIS salt displayed faster absorption and higher peak blood concentrations compared to NAP. These results indicate that the NAP-TRIS salt effectively enhanced the solubility and oral bioavailability of naproxen. In conclusion, this study underscores the potential of pharmaceutical salts, particularly NAP-TRIS, in improving the solubility and oral bioavailability of drugs with low aqueous solubility, presenting a promising avenue for advancing drug delivery and therapeutic outcomes.

Objective To compare the von Mises stresses of the pedicle screw system and the displacement of injured vertebrae using 3‐D finite element analysis, and to evaluate the curative effect of the pedicle screw system. Methods Finite element methods were used for biomechanical comparison of four posterior short segment pedicle screw fixation techniques. The different pedicle screw models are traditional trajectory (TT), Universal Spine System (USS), cortical bone trajectory (CBT), and CBT at the cranial level and pedicle screw (PS) at the caudal level (UP‐CBT). The stress distribution of the screws and connecting rods under different working conditions and the displacement of the injured vertebrae were compared and analyzed. Results After the pedicle screw system was fixed, the stress under vertical compression was mainly concentrated at the proximal end of the screw, while the stress was mainly concentrated on the connecting rod during flexion, extension, lateral flexion, and rotation. The TT group had the greatest stress during the flexion, extension, and left and right rotation. The UP‐CBT group was most stressed when the left and right sides were flexed; the stress of the USS screw system was less than that of the other three models during flexion, lateral flexion, and rotation. The maximum von Mises stress values of pedicle screws in all exercise states were 556.2, 340.7, 458.1, and 533.4 MPa, respectively. In the USS group, the displacement of the injured vertebra was small in the flexion, and the left and right lateral flexion and the right rotation were higher than in the TT group and the CBT group. The maximum displacements of the injured vertebrae in all motion states were 1.679, 1.604, 1.752, and 1.777 mm, respectively. Conclusion Universal Spine System pedicle screws are relatively less stressed under different working conditions, the risk of breakage is small, and the model is relatively stable; CBT screws do not exhibit better mechanical properties than conventional pedicle screws and USS pedicle screws.