ABSTRACT
OBJECTIVE: To investigate the impacts of particle size and preferred orientation on relative peak intensity, number of peaks and order of peak intensity in powder X-ray diffraction (PXRD) analysis of organic and inorganic pharmaceutical crystalline materials and evaluate the phase identification methods in various pharmaceutical compendiums. METHODS: The PXRD patterns of organic and inorganic materials with different particle sizes obtained by sieving or grinding were acquired and the number of diffraction peaks, peak position and intensity of diffraction peaks were compared across different samples. RESULTS: Due to preferred orientation effects, the diffraction patterns of samples with different particle sizes were apparently different, including the number of peaks, relative peak intensity and the order of the peak intensity. CONCLUSION: Scientists may get different conclusions from the results of same tests performed according to the related guiding principles of current Chinese Pharmacopeia and USP39, EP8.0, JP16 X IV pharmacopoeia for identifying the crystalline forms. The phase identification by PXRD method in current Chinese Pharmacopeia neglects the effects of preferred orientation on diffraction peaks and relative peak intensity. This guideline needs to be updated to better reflect the scientific observation in industry and align with other well accepted compendiums such as USP, EP and JP.
ABSTRACT
<p><b>OBJECTIVE</b>Canine model established for tracheal defect reconstruction, to investigate the outcome of tracheal reconstruction with combination of polypropylene and flap.</p><p><b>METHODS</b>About 3.5 to 4 centimeter cervical trachea was resected and replaced with artificial trachea made from monofilament knitted polypropylene and surgical flap. Covered stent was implanted postoperatively. Survival period and quality of life were recorded, bronchofibroscopy, X-ray films and HE sections were performed.</p><p><b>RESULTS</b>Six dogs survived well and another two died. The causes of death were respiratory failure in 1 and infection in another. Stenosis of anastomosis in 1 was recorded during survival period. The dogs started drinking and eating on the second postoperative day, no dyspnea was found. The animals were sacrificed at 2, 4, 8 weeks and 6 months after surgery. Soft tissue growth was found in polypropylene net 2 weeks after surgery and more at 4 weeks. The polypropylene net was covered completely with soft tissue at 8 weeks and 6 months postoperatively, the hardness and sustentation degree were enhanced following the growth and fibrosis of soft tissue. The squamous epithelium and columnar epithelium were observed healing well by HE staining method.</p><p><b>CONCLUSIONS</b>One-stage operative artificial trachea made from monofilament knitted polypropylene which has good histocompatibility and surgical flap is the closer artificial trachea to native trachea. It has a promising prospect in clinical use.</p>