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USP盐酸米诺环素溶出度测定已有1人参与
如题,对于USP盐酸米诺环素溶出度项下计算想跟各位同仁讨论一下。
药典原文涉及计算部分的摘录如下:
Standard stock solution: 0.11 mg/mL of USP Minocycline Hydrochloride RS in Medium
Standard solutions: Dilute the Standard stock solution with Medium to obtain solutions with final concentrations of 0.088 mg/mL, 0.0528 mg/mL, 0.0352 mg/mL, 0.022 mg/mL, and 0.0176 mg/mL.
Sample solution: dissolution solution
Injection size: 20 μL for the 4 and 24 h time points; 50 μL for the 48 and 72 h time points
Analysis: Construct a calibration curve for each sampling interval by plotting the concentration of the
Standard solutions versus peak area. Calculate the slopes and y-intercepts using linear regression analysis.
Calculate the release rate of minocycline:
Resulti = [(rUi − yi)/Si] × 10/( i × W × A)
i =sampling time, 4, 24, 48, 72 h
rUi=peak response from each of the Standard solutions at time i
yi =y-intercept of the calibration curve at sampling time i
Si =slope of the calibration curve at sampling time i
W =weight of the sample (mg)
A =amount of minocycline in the sample (mg/mg of sample) as determined in the Assay
说明:溶出介质体积10ml,
Tolerances
Time (h) Release Rate (μg/h) Average of 6 Measurements
0–4 NLT 25
4–24 NLT 1.0
24–48 NLT 0.2
48–72 NLT 0.05
具体溶出内容与计算相关性不大,未摘录,如有需要可以提供。
问题:1 按照说明,计算公式与i时间的溶出液没有关系吗?(溶出的样品溶液,Sample solution没参与计算);
2 如果公示中rUi写错,实为Sample solution的峰面积,这个计算最后的单位也无法得到ug/h?
3 不同时间进样体积不一致,这种不一致也未在计算公式中体现出来。
本人非常困惑,还请广大同仁指点指点,谢谢。 |
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