Centre for Medical Parasitology at Department of International Health, Immunology and Microbiology, University of Copenhagen, Copenhagen, Denmark.
Malar J. 2011 Aug 24;10:249. doi: 10.1186/1475-2875-10-249.
In Central and South America and Eastern and Southern Africa, Plasmodium vivax infections accounts for 71-81% and 5% of malaria cases, respectively. In these areas, chloroquine (CQ) remains the treatment of choice for P. vivax malaria. In addition, CQ has recently proven to be an effective HIV-1 therapeutic agent. There is a dire need to continue monitoring quality of CQ as there is a major influx of substandard and fake formulations into malaria-endemic countries. The use of fake/substandard drugs will result in sub-therapeutic levels endangering the patient and possibly select for parasite resistance. The aim of this study was to develop an inexpensive, simple antibody-based ELISA to measure CQ concentrations in tablets and in plasma.
A monoclonal antibody (MAb) that reacts with the N-side chain of the CQ molecule was prepared by use of a CQ analogue. A specific and reliable ELISA for detection of CQ was developed. The developed assay was validated by measuring CQ in tablets sold in Denmark, India and Sudan. Furthermore, kinetics of CQ concentrations in plasma of four volunteers, who ingested two tablets of Malarex® containing, 250 mg CQ base, were measured before drug intake, three hours later and thereafter at days 1, 3, 7, 14, 21 and 28. The same plasma samples were simultaneously measured by high performance liquid chromatography (HPLC).
The ELISA proved an easy-to-handle and very sensitive tool for the detection of CQ with a lower limit of detection at 3.9 ng/ml. ELISA levels of CQ in plasma showed high agreement with the levels obtained by HPLC (r = 0.98). The specificity in the negative control group was 100%.
The developed ELISA can be used for quality screening of CQ in pharmaceutical formulations and for drug monitoring in malaria and in other infectious diseases, such as HIV, where CQ proved to be an effective therapeutic agent. The methodology has been exploited to develop monoclonal antibodies for the drugs used in artemisinin-based combination therapy (ACT).
在中美洲和南美洲以及东非和南非，间日疟原虫感染分别占疟疾病例的 71-81%和 5%。在这些地区，氯喹（CQ）仍然是治疗间日疟原虫疟疾的首选药物。此外，CQ 最近已被证明是一种有效的 HIV-1 治疗药物。由于大量劣质和假冒配方进入疟疾流行国家，因此迫切需要继续监测 CQ 的质量。使用假冒/劣质药物会导致治疗效果不佳，危及患者，并可能选择寄生虫耐药性。本研究旨在开发一种廉价、简单的基于抗体的 ELISA 来测量片剂和血浆中的 CQ 浓度。
使用 CQ 类似物制备与 CQ 分子的 N-侧链反应的单克隆抗体（MAb）。开发了一种用于检测 CQ 的特异性和可靠的 ELISA。通过测量在丹麦、印度和苏丹销售的片剂中的 CQ 来验证所开发的测定法。此外，还测量了四名志愿者在摄入两片含有 250 毫克 CQ 碱的 Malarex®后，在药物摄入前、三小时后以及此后的第 1、3、7、14、21 和 28 天，血浆中 CQ 浓度的动力学。同时通过高效液相色谱法（HPLC）测量相同的血浆样本。
ELISA 证明是一种易于处理且非常灵敏的工具，用于检测 CQ，检测下限为 3.9 ng/ml。ELISA 水平的 CQ 与 HPLC 获得的水平高度一致（r = 0.98）。阴性对照组的特异性为 100%。
所开发的 ELISA 可用于药物制剂中 CQ 的质量筛选以及疟疾和其他传染病（如 HIV）中的药物监测，CQ 已被证明是一种有效的治疗药物。该方法已被用于开发用于基于青蒿素联合疗法（ACT）的药物的单克隆抗体。
