Objective To prepare nifedipine( NF)sustained-release pellet tablets,and study of its release behavior in vitro. Methods Soluplus was selected as a carrier to prepare solid dispersion of NF by hot melt extrusion technique( HME), and the ratio of the drug to carrier was 1:1. The samples were validated as the solid dispersion by differential scanning calorimetry(DSC). Extrusion-spheronization technique was introduced to prepare NF pellets and EudragitRS 30D was used as the coating material. The NF sustained-release tablets were prepared by direct compression of the coated pellets and suitable excipients. Results The release data in vitro proved that the drug release from the tablets was steady and complete over 24 hours. Conclusion The release of NF from sustained-release tablets is slow and steady. The method is easy to operate. The in vitro drug release pattern follows first-order kinetics.

Objective:To assess the combination of conventional ultrasound with contrast-enhanced ultrasound(CEUS)in the diagnosis of urothelial carcinoma(UC)of the renal pelvis in elderly patients.Methods:Sixty-seven elderly patients with a histopathologic diagnosis of UC of the renal pelvis and surgically treated at our hospital between April 2015 and March 2023 were retrospectively analyzed.Characteristics of regular preoperative 2D ultrasound, color Doppler flow imaging(CDFI)and CEUS were examined.Results:Of 67 patients, 49(73.13%)were found to have localized lesions in the renal pelvis and renal calyces.Lesions in 53 patients(79.10%)could be clearly identified by conventional ultrasound, with 46(86.79%)being isoechoic or hypoechoic, and 7(13.21%)being hyperechoic.Analysis of tumor blood flow by CDFI found 22 cases(41.51%)with avascular lesions, 21(39.62%)with hypovascular lesions and 10(18.87%)with hypervascular lesions.The average value of the resistance index(RI)was 0.64.Enhancement was seen in 62 lesions(92.54%)by CEUS after injection of SonoVue.Compared with the cortex of the ipsilateral kidney, a slow enhancement pattern was observed in 46(74.19%), 14(22.58%)showed simultaneous enhancement, and 2(3.23%)showed fast enhancement.At peak enhancement, 43 lesions(69.35%)had hypo-enhancement, 10(16.13%)had iso-enhancement, and 9(14.52%)had hyper-enhancement, compared with the cortex.Concerning the homogeneity of enhancement, 16(25.81%)displayed heterogeneous enhancement, with tumor necrosis or hemorrhage, and 46(74.19%)had homogeneous enhancement.When the contrast agent washout rate was assessed, a fast washout pattern was observed in 53(85.48%), synchronous washout in 6(9.68%), and slow washout in 3(4.84%).Conclusions:UC of the renal pelvis mostly shows isoechoic and hypoechoic lesions on conventional ultrasound, avascular or hypo-vascular lesions on CDFI, and slow-in, fast-out and hypo-enhancement on CEUS, compared with the cortex.Conventional ultrasound combined with CEUS can help improve the diagnostic accuracy of UC of the renal pelvis.