Quantification of a pegylated interferon-alpha2a product by a customised and validated reverse phase-high performance liquid chromatography method

The Effect of Molecular Structure on Cytotoxicity and Antitumor Activity of PEGylated Nanomedicines

Fundamental studies on the cellular uptake and drug release of PEGylated nanomedicines are beneficial to understand their fate in vivo and construct ideal nanoparticle formulations. In this work, the detailed metabolic process of PEGylated doxorubicin (Dox) nanomedicines were investigated via confocal laser scanning microscopy (CLSM), flow cytometry (FCM), cytotoxicity test, fluorescence imaging in vivo (FLIV) and liquid chromatography tandem mass spectrometry (LC-MS/MS). Among them, only LC-MS/MS could accurately determine the content of PEGylated Dox and Dox in vitro and in vivo. To the best of our knowledge, this was the first time the PEGylated Dox and released Dox were simultaneously quantified. The interplay of molecular structures, cellular uptake, drug release, and antitumor effect was well characterized. PEG with high molecular weight impeded the cellular uptake of nanoparticles, and the acid-labile hydrazone bond between Dox and PEG promoted Dox release significantly. Cellular uptake and drug release play decisive roles in cytotoxicity and antitumor effect, as evidenced by LC-MS/MS. We emphasized that LC-MS/MS would be a practicable method to quantify PEGylated drugs without complex tags, which could be more in-depth to understand the interaction between PEGylated nanomedicines and their antitumor efficacy.

Determination of recombinant Interferon-α2 in E. coli periplasmic extracts by reversed-phase high-performance liquid chromatography

Reversed-phase high-performance liquid chromatography (RP-HPLC) has been used to analyze Interferon α-2 (IFN-α2) as a pure protein or as a pharmaceutical preparation: a method for analyzing periplasmic IFN-α2 directly in osmotic shock extract has, however, never been reported. This work describes an RP-HPLC methodology for the qualitative and quantitative analysis of human IFN-α2a and IFN-α2b directly in bacterial periplasmic extracts or in purified preparations. The analytical method has been set up and validated for accuracy, precision, linearity, sensitivity and specificity. A recovery test indicated an average bias of ∼1%, intra-day and inter-day quantitative determinations presented relative standard deviations always≤5%, while the working sensitivity was of ∼0.3μg of IFN-α2 (RSD=5%). The method proved to be suitable for detecting and quantifying also glycosylated and oxidized forms and N-methionylated IFN-α2 molecules, it was, however, not able to distinguish between IFN-α2a and IFN-α2b. This rapid methodology allows the application of RP-HPLC as a powerful tool to monitor the production yield and quality of IFN-α2 in osmotic shock fluids, right after, or even during the fermentation process.