The introduction of a GMP-certified 68Ga-generator spurred the application of 68Ga-radiopharmaceuticals. Several radiosynthesis of 68Ga-radiopharmaceuticals are more efficient and robust when performed with 2-[4-(2-hydroxyethyl)piperazin-1-yl] ethanesulfonic acid (HEPES) buffer, which is considered as an impurity in the quality control (QC) procedure. Thus, prior to clinical use, QC must be conducted to ensure that HEPES does not exceed the maximum dose of 200 μg/V Injected as described in European Pharmacopoeia (Ph Eur) for edotreotide. However, when applying the thin-layer chromatography (TLC) method described in the Ph Eur to quantify the HEPES amount present in the 68Ga-octreotide or in the remaining 68Ga-radiopharmaceuticals that were tested, no amount was detectable after 4 min of iodine incubation. Here we tested our modified TLC method and validate a new high-performance liquid chromatography (HPLC) method to quantify HEPES in 68Ga-radiopharmaceuticals and compare it to the TLC-method described in Ph Eur. In addition, samples collected from various institutes were tested to evaluate whether the synthesis of different 68Ga-radiopharmaceuticals or the use of different synthesis methods could affect the amounts of HEPES. HEPES could not be detected by the TLC method described in the Ph Eur within 4 min incubation in an iodine-saturated chamber. As for our modified TLC method, only after 2 h, spots were only visible > 1 mg/mL. The HPLC method had a limit-of-quantification (LOQ) of 3 μg/mL and a limit-of-detection (LOD) of 1 μg/mL. From the three 68Ga-radiopharmaceuticals tested, only in the [68Ga]Ga-NODAGA-Exendin samples exceeding amounts of HEPES were found and its concentration in the [68Ga]Ga-NODAGA-Exendin was significantly higher, when compared to [68Ga]Ga-DOTATOC and [68Ga]Ga-PSMA-11. The TLC method described in Ph Eur and our modified TLC method may not be sufficiently sensitive and thus unsuitable to use for QC release. The new HPLC method was sensitive, quantitative, reproducible and suitable for QC release. With this method, we were able to determine that some 68Ga-radiopharmaceuticals may exceed the HEPES limit of 200 μg/ V Injected. This new analytical system would allow correcting for the maximum injected dose in order not to exceed this amount.

中文翻译：

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68Ga-放射性药物中HEPES定量的新灵敏方法。

经GMP认证的68Ga发生器的推出刺激了68Ga放射性药物的应用。使用2- [4-（2-羟乙基）哌嗪-1-基]乙磺酸（HEPES）缓冲液进行68Ga放射性药物的几种放射合成会更有效，更可靠，在质量控制（QC）中将其视为杂质程序。因此，在临床使用前，必须进行质量控制以确保HEPES不会超过按照欧洲药典（Ph Eur）注射的依托肽的最大剂量200μg/ V。但是，当应用Ph Eur中描述的薄层色谱（TLC）方法定量检测68Ga-奥曲肽或剩余的68Ga-放射性药物中存在的HEPES量时，在碘孵育4分钟后未检测到任何量。在这里，我们测试了改进的TLC方法，并验证了一种新的高效液相色谱（HPLC）方法，以定量68Ga放射性药物中的HEPES，并将其与Ph Eur中描述的TLC方法进行比较。此外，还对从各个机构收集的样品进行了测试，以评估不同68Ga-放射性药物的合成或使用不同合成方法是否会影响HEPES的含量。在碘饱和的培养箱中孵育4分钟后，无法通过Ph Eur中所述的TLC方法检测到HEPES。对于我们改进的TLC方法，仅在2 h后，斑点只有> 1 mg / mL才可见。HPLC方法的定量限（LOQ）为3μg/ mL，检测限（LOD）为1μg/ mL。从测试的三种68Ga放射性药物中，与[68Ga] Ga-DOTATOC和[68Ga] Ga-相比，仅在[68Ga] Ga-NODAGA-Exendin样品中发现了超过HEPES的样品，并且在[68Ga] Ga-NODAGA-Exendin中的浓度明显更高。 PSMA-11。Ph Eur中描述的TLC方法和我们改进的TLC方法可能不够灵敏，因此不适合用于QC发布。新的HPLC方法灵敏，定量，可重现并且适合QC释放。通过这种方法，我们能够确定某些68Ga放射性药物可能会超过HEPES注射200μg/ V的限值。这种新的分析系统将允许校正最大注射剂量，以不超过该剂量。Ph Eur中描述的TLC方法和我们改进的TLC方法可能不够灵敏，因此不适合用于QC发布。新的HPLC方法灵敏，定量，可重现并且适合QC释放。通过这种方法，我们能够确定某些68Ga放射性药物可能会超过HEPES注射200μg/ V的限值。这种新的分析系统将允许校正最大注射剂量，以不超过该剂量。Ph Eur中描述的TLC方法和我们改进的TLC方法可能不够灵敏，因此不适合用于QC发布。新的HPLC方法灵敏，定量，可重现并且适合QC释放。通过这种方法，我们能够确定某些68Ga放射性药物可能会超过HEPES注射200μg/ V的限值。这种新的分析系统将允许校正最大注射剂量，以不超过该剂量。