dxy

dlxia:
1.脂溶性高、弱碱性、分子量<200和离解度高的药物，在母乳中含量就高。
2.药物是以被动扩散方式排到乳汁中，乳汁中药物浓度与母体中药物浓度梯度起主要作用，药物排出数量和速度与乳腺的血流量和乳汁中脂肪含量也相关，但药物含量很少超过哺乳妇女摄入药量的1%～2%。
3.乳汁中药物浓度大部分较母体循环中药物浓度低，例如哺乳期妇女服用红霉素、磺胺类、异烟肼、甲硝唑，乳汁中各药物浓度约为血清中该药物浓度的50%，而青霉素、头孢菌素在乳汁中的浓度仅不足血清中该药物浓度25%。
4.假体乳房分解产物是否会被分泌乳汁中，缺少临床资料。

hub4:
First of all, nearly all drugs transfer into breast milk to some extent, with rare exceptional(such as Heparin and Insilin because of a high molecular weight over 1,000g/mol) , influenced by protein binding, lipid solubility, ionisation, pKa of the drug and the PH of the milk. In a word, drug transfer from maternal plasme to milk is by passive diffusion across biological membranes, and greatest in the presence of low maternal plasma protein binding and high lipid solubility.
Secondly, since milk PH(7) is significantly lower than plasma(7.4), weak acids will ionize in the maternal plasma and reduce their passage into milk, and weak bases are nonionized and will, thus, reach the more acidic milk where they may be trapped. That is mean, weak acids tend to have lower milk/plasma concentration ratios and higher concentrations in milk, such as anticoagulants, antimetabolites, antithyroid agents, atropine, bromides, cathartics, ergot, iodides, mercurials, metronidazole, narcotics, and radioactive agents.
Thirdly, the breast milk concentration usually does not exceed the maternal plasma concentration, and even when the M/P ratio approaches 1.0.
Last, neither silicone mor its components ciuld be measured in the breast milk of women with silicone implants.

参考答案（请战友指正）
1 哪些因素药理因素对乳汁中的能够分泌的药物来说是最重要的
有很多药物具有影响母体的药代动力学的因素，因而影响药物在母乳中的分布，这些药理因素包括：
与血浆蛋白结合
离子化
脂溶性程度
分子量
然而，这些因素独自并不能控制药物在乳汁中的分布，乳汁分泌还包括被动转运和载体介导过程
2 乳汁中药物浓度与母体中药物浓度的相关性如何
乳汁血浆药物浓度比值是指乳汁中药物浓度和母体血浆中药物浓度的比值。众所周知此比值是随时间不断变化的，因此用时间-平均比率反映药物的药代动力学，单个时间点比率很容易误导，因为其与时间-平均比率偏差太远。
3 乳汁中药物浓度大部分较母体循环中药物浓度高，此说法对否
虽然没有将所有的药物都纳入研究，但在研究过的药物中，乳汁血浆药物浓度比值大多数比率小于1。大约25%的药物比值大于1，15%的药物比值大于2。然而最近，此种测量方法的重要性得到质疑，因为每单位时间婴儿消化的药物使母亲体内药物浓度明显低于治疗浓度或中毒效应
4 植入硅树脂假体乳房的妇女是否会分泌带有硅树脂分解产物的乳汁
目前为止，在植入硅树脂假体乳房的妇女的乳汁中没有检测到硅树脂及其的分解产物

英文参考答案
1 What drugs factors are important for drug expression in breast milk?
A number of drug characteristics can influence maternal pharmacokinetics and thereby influence how much is expressed in breast milk, including:
•plasma protein binding
•ionization
•degree of lipophilicity
•molecular weight
However, these alone do not control how much drug excretion into the breast milk occurs, as excretion involves both passive and carrier mediated processes (1). Ultimately, however, the rate of neonatal drug clearance is the most important factor in determining the overall drug effect (2).
2 How are the concentrations of drug in breast milk relative to the maternal circulation reported?
The milk-to-plasma drug concentration ratio reports the ratio of a drug in the breast milk versus maternal plasma. As this ratio is known to change over time, a time-averaged ratio is utilized to report the drug's kinetics. Single time point ratio information is often misleading, as it has been known to deviate significantly from time-averaged values (3).
3 Do most drugs appear in the breast milk at greater concentrations than in maternal circulation?
Although all drugs have not been studied, of those that have milk-to-plasma ratios reported, most have a ratio of less than 1. Approximately 25% have a ratio of greater than 1, and 15% have a ratio of greater than 2 (4). Recently, however, the importance of these measurements has been discounted, as the amount of drug ingested by the infant per unit time almost always results in amounts significantly lower than needed for any therapeutic or toxic effect (2).
4 Can women with silicone breast implants secrete silicone breakdown products into breast milk?
To date, neither silicone or any of its breakdown products have been measured in breast milk in women with silicone breast implants (5).