其中:
ARL = the acceptable residue level in the next drug product 下一产品中可接受残留水平
MDD = the minimum daily dose of the active of the cleaned product  已清洁产品活性成分的最小日剂量
SF = the safety factor, which is typically 0.001
安全系数,通常为 0.001(放在分母就是1000)
LDD = the largest daily dose of the next drug product to be manufactured in the same equipment 同一设备中生产的下一制剂的最大日剂量
其中:
NOAEL = No Observable Adverse Effect Level
无可见损害作用水平
BW = body weight of patient taking next product
服用下一产品患者体重
UFC = a composite uncertainty factor determined from such factors as interspecies differences,intraspecies differences, subchronic to chronic extrapolation, LOAEL to NOAEL extrapolation,and database completeness
综合不确定度,由种间差异、种内差异、亚慢性到慢性的推断、最低可见损害作用水平
到无可见损害作用水平的推断和数据库完整性等因素确定
MF = a factor based on the judgment of the toxicologist
基于毒理学家判断的因子
PK = a pharmacokinetic factor to account for different routes of exposures
与给药途径相关的药代动力学因子
ADE和ARL的关系为:ARL=ADE/LDD
公式中的UFC,MF,PK不易得到,所以Y一般不用此种方法计算ARL,而是大部分使用第二种方法。即基于半数致死剂量计算ARL的方法。
其中:
SDI = Safe Daily Intake of the residue 残留每日安全摄入量
NOEL = No Observable Effect Level无可见作用水平
MF2 = modifying factor or factors, selected by the toxicologist 修正因子,由毒理学家确定,修正因子一般不超过 1000
LD50= the 50% lethal dose of the target residue in an animal, typically in mg/kg of body weight (by the appropriate route of administration)目标残留物在动物中的半数致死剂量,通常以mg/kg体重表示(采用适当给药途径)。
BW = body weight of patient taking next product 服用下一产品患者的体重
MF1 = modifying factor or factors, selected by the toxicologist 修正因子,由毒理学家确定,修正因子一般不超过 1000。
因为LD50容易查到,所以通常使用此种方法。LD50可以通过查找药品的MSDS,MERCK索引,说明等途径检索到。
具体案例:假设LD50 = 100 mg/kg,BW = 60 kg,MBS = 1000 L,LDD = 10ml,SF = 100,000则ARL可得:
3、ICH Q3C中THF(四氢呋喃)案例
Groups of 50 male and 50 female rats were exposed to 0, 200, 600, or 1,800 ppm tetrahydrofuran by inhalation, 6 hours per day, 5 days per week, for 105 weeks. Under the conditions of the studies, there was some evidence of carcinogenic activity of THF in male rats due to increased incidences of adenoma or carcinoma of the kidney.
分析整个实验过程,可知:
1、试验动物的种属:大鼠,F1=5。
2、试验时间:105周,大鼠的整个生命周期,F3=1。
3、产生的病变的具体情况:有致癌性的证据。严重的毒性,F4=10
4、产生病变的最低浓度LOEL:吸入试验,200ppm
5、接触时间(用于计算接触总量):每天6小时,每周5天。
6、其他:F2=10,F5=1,体重调整50kg。
7、THF分子量72.10