利福霉素类抗生素的晶型与血（尿）药浓度

目的：探讨利福霉素类抗生素的衍生物（利福平，利福定，利福喷丁）的晶型与血（尿）药浓度的关系。方法：通过正常人空腹口服各不同型晶粉，定时收集血、尿标本，用杯碟法测定血、尿药含量。结果：同一药物的不同晶型粉，显示出各自不同的结构图形、溶解度及生物有效度的特性。结论：凡是稳定的晶型均具恒定的结构及生物有效度，利福霉素类药物的含水量，对其晶型的稳定性至关重要，干燥失重，不是越低越好。

Relationship between the rifamycins polymorphic forms and the drug content in plasma(urine)

Objective:To study the relations between the polymorphic forms of rifamycin derivatives rifampicin(RFP), rifapentin(RFT) and rifamdeni(IPR) and the drug content in plasma(urine).Methods:These polymorphic forms were tested by x ray powder diffraction and given to the healthy people who were divided as REP group(9 men each) and IPR group(4 men each). At various time after administration, plasma and urine samples were collected. The antibiotic content was determined by microbiological assay.Results:Each polymorphic form solid has it's x ray powder diffraction pattern and this different solid form shows different stability, formulability and bioavailability.Conclusion:A stable crystalline form is characteristic of constant bioavailiability and structure. The moisture is critical in the structure of rifamycins crystalite. The idea that the lower the loss on drying the better is not true.