Advanced Formulation Approaches for Emerging Therapeutic Technologies.

In addition to proteins, discussed in the Chapter "Advances in Vaccine Adjuvants: Nanomaterials and Small Molecules", there are a wide range of alternatives to small molecule active ingredients. Cells, extracellular vesicles, and nucleic acids in particular have attracted increasing research attention in recent years. There are now a number of products on the market based on these emerging technologies, the most famous of which are the mRNA-based vaccines against SARS-COV-2. These advanced therapeutic moieties are challenging to formulate however, and there remain significant challenges for their more widespread use. In this chapter, we consider the potential and bottlenecks for developing further medical products based on these systems. Cells, extracellular vesicles, and nucleic acids will be discussed in terms of their mechanism of action, the key requirements for translation, and how advanced formulation approaches can aid their future development. These points will be presented with selected examples from the literature, and with a focus on the formulations which have made the transition to clinical trials and clinical products.

Lipid-peptide nanocomplexes for mRNA delivery in vitro and in vivo.

Despite recent advances in the field of mRNA therapy, the lack of safe and efficacious delivery vehicles with pharmaceutically developable properties remains a major limitation. Here, we describe the systematic optimisation of lipid-peptide nanocomplexes for the delivery of mRNA in two murine cancer cell types, B16-F10 melanoma and CT26 colon carcinoma as well as NCI-H358 human lung bronchoalveolar cells. Different combinations of lipids and peptides were screened from an original lipid-peptide nanocomplex formulation for improved luciferase mRNA transfection in vitro by a multi-factorial screening approach. This led to the identification of key structural elements within the nanocomplex associated with substantial improvements in mRNA transfection efficiency included alkyl tail length of the cationic lipid, the fusogenic phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), and cholesterol. The peptide component (K16GACYGLPHKFCG) was further improved by the inclusion of a linker, RVRR, that is cleavable by the endosomal enzymes cathepsin B and furin, and a hydrophobic motif (X-S-X) between the mRNA packaging (K16) and receptor targeting domains (CYGLPHKFCG). Nanocomplex transfections of a murine B16-F10 melanoma tumour supported the inclusion of cholesterol for optimal transfection in vivo as well as in vitro. In vitro transfections were also performed with mRNA encoding interleukin-15 as a potential immunotherapy agent and again, the optimised formulation with the key structural elements demonstrated significantly higher expression than the original formulation. Physicochemical characterisation of the nanocomplexes over time indicated that the optimal formulation retained biophysical properties such as size, charge and mRNA complexation efficiency for 14 days upon storage at 4 °C without the need for additional stabilising agents. In summary, we have developed an efficacious lipid-peptide nanocomplex with promising pharmaceutical development properties for the delivery of therapeutic mRNA.

Selective Laser Sintering 3D Printing of Orally Disintegrating Printlets Containing Ondansetron.

The aim of this work was to explore the feasibility of using selective laser sintering (SLS) 3D printing (3DP) to fabricate orodispersable printlets (ODPs) containing ondansetron. Ondansetron was first incorporated into drug-cyclodextrin complexes and then combined with the filler mannitol. Two 3D printed formulations with different levels of mannitol were prepared and tested, and a commercial ondansetron orally disintegrating tablet (ODT) product (Vonau® Flash) was also investigated for comparison. Both 3D printed formulations disintegrated at ~15 s and released more than 90% of the drug within 5 min independent of the mannitol content; these results were comparable to those obtained with the commercial product. This work demonstrates the potential of SLS 3DP to fabricate orodispersible printlets with characteristics similar to a commercial ODT, but with the added benefit of using a manufacturing technology able to prepare medicines individualized to the patient.

Direct powder extrusion 3D printing: Fabrication of drug products using a novel single-step process.

Three-dimensional (3D) printing is revolutionising how we envision manufacturing in the pharmaceutical field. Here, we report for the first time the use of direct powder extrusion 3D printing: a novel single-step printing process for the production of printlets (3D printed tablets) directly from powdered materials. This new 3D printing technology was used to prepare amorphous solid dispersions of itraconazole using four different grades of hydroxypropylcellulose (HPC - UL, SSL, SL and L). All of the printlets showed good mechanical and physical characteristics and no drug degradation. The printlets showed sustained drug release characteristics, with drug concentrations higher than the solubility of the drug itself. The printlets prepared with the ultra-low molecular grade (HPC - UL) showed faster drug release compared with the other HPC grades, attributed to the fact that itraconazole was found in a higher percentage as an amorphous solid dispersion. This work demonstrates the potential of this innovate technology to overcome one of the major disadvantages of fused deposition modelling (FDM) 3D printing by avoiding the need for preparation of filaments by hot melt extrusion (HME). This novel single-step technology could revolutionise the preparation of amorphous solid dispersions as final formulations and it may be especially suited for preclinical studies, where the quantity of drugs is limited and without the need of using traditional HME.