Visualization of Protonation/Deprotonation of Active Pharmaceutical Ingredient in Solid State by Vapor Phase Amine-Selective Alkyne Tagging and Raman Imaging

Precision Printing of Customized Cylindrical Capsules with Multifunctional Layers for Oral Drug Delivery

Advances in personalized medicine will require custom drug formulations and delivery mechanisms. Herein, we demonstrate a new type of personalized capsule comprising of printed concentric cylindrical layers with each layer having a distinctive functional drug component. Poly ε-caprolactone (PCL) with paracetamol (APAP) and chlorpheniramine maleate (CM), synergistic drugs commonly used to alleviate influenza symptoms, are printed as an inner layer and outer layer, respectively, via microscaled electrohydrodynamic (EHD) printing. Polyvinylpyrrolidone (PVP) nanofibers are embedded as interlayers between the two printed PCL-drug layers using electrospinning (ES) techniques. The complete concentric cylindrical capsule with a 6 mm inner diameter and 15 mm length can be swallowed for oral drug delivery. After dissolution of the PVP interlayer, the capsule separates in two, with inner and outer capsules for continuous drug dosing and targeting. Imaging was achieved using a 3T MRI system which allowed temporal observations of the targeted release through the incorporation of nanoparticles (Fe₃O₄). The morphology and structure, chemical composition, mechanical properties, and biocompatibility of the capsules were studied in vitro. In summary, this new type of custom printed and electrospun capsule that enabled component separation, targeted drug release may advance personalized medicine via multidrug oral delivery.

Recent advances in the applications of vibrational spectroscopic imaging and mapping to pharmaceutical formulations

Vibrational spectroscopic imaging and mapping approaches have continued in their development and applications for the analysis of pharmaceutical formulations. Obtaining spatially resolved chemical information about the distribution of different components within pharmaceutical formulations is integral for improving the understanding and quality of final drug products. This review aims to summarise some key advances of these technologies over recent years, primarily since 2010. An overview of FTIR, NIR, terahertz spectroscopic imaging and Raman mapping will be presented to give a perspective of the current state-of-the-art of these techniques for studying pharmaceutical samples. This will include their application to reveal spatial information of components that reveals molecular insight of polymorphic or structural changes, behaviour of formulations during dissolution experiments, uniformity of materials and detection of counterfeit products. Furthermore, new advancements will be presented that demonstrate the continuing novel applications of spectroscopic imaging and mapping, namely in FTIR spectroscopy, for studies of microfluidic devices. Whilst much of the recently developed work has been reported by academic groups, examples of the potential impacts of utilising these imaging and mapping technologies to support industrial applications have also been reviewed.

Fluorescence-Based High-Throughput Salt Screening

The present study reports a high-throughput screening method for the salt formation of amine-containing active pharmaceutical ingredients (APIs) based on fluorescence measurements. A free form amine API was alkynylated by a solid-vapor reaction using propargyl bromide, and a fluorescent compound was produced by a subsequent reaction using 9-azidomethylanthracene. In contrast, salts were inert to propargyl bromide; thus, no fluorescence was observed. Samples for salt screening were prepared by grinding haloperidol with various counter acids, and these mixtures were derivatized in a 96-well microplate to determine whether the salt formation had occurred between haloperidol and the counter acids. Samples that turned into fluorescent and nonfluorescent were confirmed to be free form and salt form, respectively, using powder X-ray diffraction and Raman spectroscopy. In conclusion, our method adequately functions as an indicator of the salt formation of amine APIs. Further, this method allows for the rapid evaluation of the salt formation of APIs using 96-well microplates without the need for special reagents or techniques; thus, it is valuable for the discovery of an optimal salt form of newly developed amine APIs in the pharmaceutical industry.