在目前发现的抗组胺药物中,除极个别品种外, 大部分在口服后可快速完全吸收,并在服用后1小时 -4小时达血药浓度峰值。但因抗组胺药物在推荐剂量 下的血浆浓度变化大,使药物代谢和组织分布差异性 大。在药代动力学范畴内,将药物的最低分布容积(Vd) 与靶向受体有效治疗浓度的治疗目标相联系,可避免 药物在器官内无效或产生毒性。 有一些药物广泛使用并分布全身各器官,是因为 其具有脂溶性。这种物质可在血液里结合成非离子型, 并成为口服后进行主动转运的先决条件。脂溶性对器 官转运的选择无影响,而是通过主动转运使药物通过 所有细胞膜,理想的药物分布容积是使用的药物剂量 最低,达到选择性受体的疗效最好,同时避免药物的 无效和毒性发生。因此,药物分布容积比其治疗效果 还重要。 低药物分布容积可定义为:药物容积量低于细胞 Among the currently available antihistamines, most of them, except for a few individual species, can be rapidly and completely absorbed after oral administration and reach the peak of plasma concentration 1 hour to 4 hours after taking the antihistamines. However, the plasma concentrations of antihistamines at the recommended doses vary greatly, resulting in significant differences in drug metabolism and tissue distribution. In the field of pharmacokinetics, linking the lowest volume of drug (Vd) to the therapeutic target of a therapeutically effective concentration of a targeted receptor can prevent the drug from becoming ineffective or toxic in the organ. There are some drugs that are widely used and distribute throughout the body because of their fat-soluble properties. This substance binds non-ionic in the bloodstream and becomes a prerequisite for active delivery after oral administration. Lipolysis has no effect on the choice of organ transport but rather on the active transport of the drug through all cell membranes. The ideal drug distribution volume is the one that uses the lowest dose of drug and achieves the best response to the selective receptor while avoiding ineffectiveness and toxicity of the drug occur. Therefore, the volume of drug distribution than its therapeutic effect is also important. Low drug distribution volume can be defined as: drug volume is lower than cells