Simultaneous Chromatographic Quantitation of Drug Substance and Excipients in Nanoformulations Using a Combination of Evaporative Light Scattering and Absorbance Detectors

Abstract

Nanomedicines including lipid-and polymer-based nanoparticles and polymer−drug conjugates enable targeted drug delivery for the treatment of numerous diseases. Quantitative analysis of components in nanomedicines is routinely performed to characterize the products to ensure quality and property consistency but has been mainly focused on the active pharmaceutical ingredients (APIs) in academic publications. It has been increasingly recognized that excipients in nanomedicines are critical in determining the product quality, stability, consistency, and safety. APIs are often analyzed by highperformance liquid chromatography (HPLC), and it would be convenient if the same method can be applied to excipients to robustly quantify all components in nanomedicines. Here, we report the development of a HPLC method that combined an evaporative light scattering (ELS) detector with an UV−vis detector to simultaneously analyze drugs and excipients in nanomedicines. This method was tested on diverse nanodrug delivery systems, including a niosomal nanoparticle encapsulating a phytotherapeutic, a liposome encapsulating an immune boosting agent, and a PEGylated peptide. This method can be utilized for a variety of applications, such as monitoring drug loading, studying drug release, and storage stability. The information obtained from the analyses is of importance for nanomedicine formulation development.

Analysis of complex mixtures with benchtop nuclear magnetic resonance: Solvent suppression with T2 and diffusion filters

“…The WET solvent suppression technique results in both a strong attenuation in peak intensity and, more importantly, narrowing of the spectral region in which the residual solvent peak is which is critical for quantifying real-world samples. The examples in this paper show water as the main solvent for its relevance in pharmaceutical excipients; however, the WET solvent suppression pulse sequence can also be implemented to suppress multiple solvent peaks and incorporate 13 C decoupling to address the strong 13 C-satellites signals from organic solvents. We demonstrated the use of T 2 and diffusion filters combined with the WET solvent suppression to analyze complex pharmaceutical excipient samples.…”

“…The WET suppression block is followed by a CPMG echo train with an echo time of 1 ms. The carbon-decoupling block is on when using organic solvents to suppress 13 C satellites from the solvents and the analytes; it was not used in the excipient mixtures prepared in water.…”

“…The concentrations of these pharmaceutical excipients play an important role in maintaining the appropriate conditions to stabilize the therapeutic proteins. The identification and quantification of excipient mixtures are usually performed using different analytical techniques including spectroscopic, chromatographic, and electrophoretic techniques (e.g., Raman, near IR spectroscopy, high‐performance liquid chromatography coupled with different detectors [UV, refractive index detector‐RID, evaporative light scattering detector]) 13,14 . There are also other methods that are specifically designed for certain classes of excipients such as L‐amino acid quantitation kit for amino acid excipients, 15 which can be more costly to perform.…”