Aguilar Ponce J L, Flores-Picazo Y, Pérez-Urizar J, Castañeda-Hernández G, Zinser-Sierra J W, Dueñas-González A, Calderón-Flores E, Segura-Pacheco B A, de la Garza-Salazar J
Instituto Nacional de Cancerología, México, D.F., Mexico.
Arch Med Res. 1999 May-Jun;30(3):212-5. doi: 10.1016/s0188-0128(99)00014-7.
Oral etoposide administration is a suitable alternative to the intravenous route; therefore, commercial capsules have been developed. Before these capsules were available in Mexico, we studied drug bioavailability after oral administration of the intravenous etoposide solution (IVES).
Eight adult cancer patients received a 50-mg oral etoposide dose as IVES and blood samples were collected over a period of 24 h. Plasma etoposide concentration was determined by high-performance liquid chromatography, plasma concentration against time curves were constructed, and bioavailability parameters were calculated.
Oral IVES yielded an adequate bioavailability profile because Cmax was 2.38 +/- 0.30 micrograms/mL, AUC was 12.87 +/- 2.02 micrograms/mL and half-life was 6.72 +/- 0.97 h.
Considering that the pharmacokinetic aim is to maintain plasma concentrations between 0.5 and 1.0 microgram/mL for several hours while avoiding high concentrations, i.e., of 10 micrograms/mL or higher, oral administration of 50-mg etoposide as IVES appears to be a suitable dosing option. In addition, oral IVES is considerably less expensive than intravenous administration in terms of both drug presentation and administration.
口服依托泊苷是静脉给药途径的合适替代方法；因此，已开发出商业胶囊。在这些胶囊在墨西哥上市之前，我们研究了静脉用依托泊苷溶液（IVES）口服后的药物生物利用度。
8名成年癌症患者接受了50毫克口服依托泊苷剂量的IVES，在24小时内采集血样。通过高效液相色谱法测定血浆依托泊苷浓度，绘制血浆浓度-时间曲线，并计算生物利用度参数。
口服IVES产生了足够的生物利用度曲线，因为Cmax为2.38±0.30微克/毫升，AUC为12.87±2.02微克/毫升，半衰期为6.72±0.97小时。
考虑到药代动力学目标是在数小时内将血浆浓度维持在0.5至1.0微克/毫升之间，同时避免高浓度，即10微克/毫升或更高，口服50毫克依托泊苷作为IVES似乎是一种合适的给药选择。此外，就药物剂型和给药方式而言，口服IVES比静脉给药便宜得多。
