PVP/aprepitant microcapsules produced by supercritical antisolvent process.

The supercritical antisolvent (SAS) process was a green alternative to improve the low bioavailability of insoluble drugs. However, it is difficult for SAS process to industrialize with limited production capacity. A coaxial annular nozzle was used to prepare the microcapsules of aprepitant (APR) and polyvinylpyrrolidone (PVP) by SAS with N, N-Dimethylformamide (DMF) as solvent. Meanwhile, the effects of polymer/drug ratio, operating pressure, operating temperature and overall concentration on particles morphology, mean particle diameter and size distribution were analyzed. Microcapsules with mean diameters ranging from 2.04 µm and 9.84 µm were successfully produced. The morphology, particle size, thermal behavior, crystallinity, drug content, drug dissolution and residual amount of DMF of samples were analyzed. The results revealed that the APR drug dissolution of the microcapsules by SAS process was faster than the unprocessed APR. Furthermore, the drug powder collected every hour is in the kilogram level, verifying the possibility to scale up the production of pharmaceuticals employing the SAS process from an industrial point of view.

Locking Compression Plate as an External Fixator for the Treatment of Tibia Infected Bone Defects.

PURPOSE: This study was designed to observe the medium-term efficacy of an induced membrane technique combined with a locking compression plate as an external fixator for the treatment of tibia infected bone defects. METHODS: Patients with a tibial infection were admitted to our department between January 2013 and November 2014. All patients were treated with the induced membrane technique. In the first stage, polymethyl methacrylate (PMMA) cement was implanted in the defects after debridement and then fixed with a locking compression plate (LCP) as an external fixator. In the second stage, bone grafts were implanted to rebuild the defects. The external plates were replaced with nails in 57 patients (internal group), and the remaining 30 patients were not exchanged with fixation (external group). The infection control rate, bone union rate, and complications of the two groups were compared. RESULTS: Eighty-seven patients were enrolled in this study, and all patients had a minimum follow-up of 5 years (average 62.8 months) after grafting. Eighty-three patients (95.4%) achieved bone union, and the average union time was 6.77 months. Five patients (5.7%) experienced recurrence of infection. Complications included pin tract infection, fixation loosening, deformity connection, and limitation of joint range of motion (ROM). No significant differences in the infection control rate or bone defect union rate were noted between the two groups. The overall rate of complications in the external group was 50%, which was greater than that noted in the internal group (21.1%). CONCLUSIONS: Locking compression plates are external fixators with smaller sizes that are easier to operate than conventional annular fixators or assembled external fixators. The use of locking compression plates in combination with the induced membrane technique in the treatment of tibia infected bone defects can achieve good clinical efficacy after medium-term follow-up.