From green innovations in oligopeptide to oligonucleotide sustainable synthesis: differences and synergies in TIDES chemistry

The growing market for therapeutic peptides and oligonucleotides (TIDES) draws attention towards their manufacture, aiming at efficient and sustainable productive processes in view of the predicted massive application of these molecules in several therapeutic areas in the near future. A comparative assessment of the principal innovations in the synthesis of these molecules is described herein, with a major focus on solid-phase synthesis (SPS), describing particularly the less-explored field of solid-phase oligonucleotide synthesis (SPOS). A head-to-head analysis of SPS techniques applied to peptides and oligonucleotides was performed, highlighting the strengths and weaknesses of these iterative synthetic approaches. The green innovations introduced in solid-phase peptide synthesis (SPPS), namely reduction or replacement with greener alternatives of solvents and reagents, and implementations in purification techniques, were reviewed and projected to potential targets and sustainable practices in modern SPOS, including their application in P(v) chemistry for the synthesis of stereopure oligonucleotides. By a comparative analysis, the key elements for the development of overall green procedures for oligonucleotide manufacturing were emphasized. In addition, due to the intrinsically more sustainable profile of liquid-phase synthetic techniques (LPS), recent advancements in the field reported for both TIDES were analyzed to prove the industrial interest in the manufacturing of these classes of molecules, underlining the importance of investment and modernization in the development of stronger and greener synthetic pathways

Steps towards sustainable solid phase peptide synthesis: use and recovery ofN-octyl pyrrolidone

The investigation of new green biogenic pyrrolidinones as alternative solvents toN,N-dimethylformamide (DMF) for solid phase peptide synthesis (SPPS) led to the identification ofN-octyl pyrrolidone (NOP) as the best candidate. NOP showed good performances in terms of swelling, coupling efficiency and low isomerization generating peptides with very high purity. A mixture of NOP with 20% dimethyl carbonate (DMC) allowed a decrease in solvent viscosity, making the mixture suitable for the automated solid-phase protocol. Aib-enkephalin and linear octreotide were successfully used to test the methodologies. It is worth noting that NOP, DMC and the piperidine used in the deprotection step could be easily recovered by direct distillation from the process waste mixture. The process mass intensity (PMI), being reduced by 63-66%, achieved an outstanding value representing a clear step forward in achieving green SPPS

Sustainability in peptide chemistry: current synthesis and purification technologies and future challenges.

Developing greener synthesis processes is an inescapable necessity to transform the industrial landscape, mainly in the pharmaceutical sector, into a long-term, sustainable reality. In this context, the renaissance of peptides as medical treatments, and the enforcement of more stringent sustainability requirements by regulatory agencies, pushed chemists toward the introduction of sustainable processes to prepare highly pure, active pharmaceutical ingredients (APIs). Innovative upstream (synthesis) and downstream (purification) methodologies have been developed during the last 5 years with the introduction and optimization of several technologies in solid-phase peptide synthesis (SPPS), liquid-phase peptide synthesis (LPPS), chemoenzymatic peptide synthesis (CEPS), and chromatographic procedures. These innovations are also moving toward the introduction of continuous processes that represent one of the most important targets for iterative processes. This overview discusses the most recent efforts in making peptide chemistry greener. The extensive studies that were carried out on green solvents, reaction conditions, auxiliary reagents and purification technologies in the peptide segment can be useful to other fields of organic synthesi

Dimethyl carbonate as a green alternative to acetonitrile in reversed-phase liquid chromatography. Part I: Separation of small molecules

: Nowadays, environmental problems are drawing the attention of governments and international organisations, which are therefore encouraging the transition to green industrial processes and approaches. In this context, chemists can help indicate a suitable direction. Beside the efforts focused on greening synthetic approaches, currently also analytical techniques and separations are under observation, especially those employing large volumes of organic solvents, such as reversed-phase liquid chromatography (RPLC). Acetonitrile has always been considered the best performing organic modifier for RPLC applications, due to its chemical features (complete miscibility in water, UV transparency, low viscosity etc); nevertheless, it suffers of severe shortcomings, and most importantly, it does not fully comply with Environmental, Health and Safety (EHS) requirements. For these reasons, alternative greener solvents are being investigated, especially easily available alcohols. In this work, chromatographic performance of the most common solvents used in reversed-phase chromatography, i.e., acetonitrile, ethanol and isopropanol, have been compared to a scarcely used solvent, dimethyl carbonate (DMC). The analytes of interest were two small molecules, caffeine and paracetamol, whose kinetics and retention behaviour obtained with the four solvents have been compared, and all contributions to band broadening have been assessed. Results about kinetic performance are very promising, indicating that a small amount (7 % v/v) of DMC is able to produce the same efficiency as a 2.5-times larger ACN volume (18 % v/v), and larger efficiency than alcohols. This paper reports, for the first time, fundamental studies concerning the mass transfer phenomena when DMC is used as an organic solvent in RPLC, and, together with the companion paper, represents the results of a research whose final aim was to discover whether DMC is suitable for chromatographic applications both in linear and preparative conditions

Expanding the use of dynamic electrostatic repulsion reversed-phase chromatography: An effective elution mode for peptides control and analysis

Bioactive peptides are increasingly used in clinical practice. Reversed-phase chromatography using formic or trifluoroacetic acid in the mobile phase is the most widely used technique for their analytical control. However, sometimes it does not prove sufficient to solve challenging chromatographic problems. In the search for alternative elution modes, the dynamic electrostatic repulsion reversed-phase was evaluated to separate eight probe peptides characterised by different molecular weights and isoelectric points. This technique, which involves TBAHSO4 in the mobile phase, provided the lowest asymmetry and peak width at half height values and the highest in peak capacity (about 200 for a gradient of 30 min) and resolution concerning the classic reversed-phase. All analyses were performed using cutting-edge columns developed for peptide separation, and the comparison of the chromatograms obtained shows how the dynamic electrostatic repulsion reversed-phase is an attractive alternative to the classic reversed-phase

Investigating the Neuroprotective Effects of Turmeric Extract: Structural Interactions of β-Amyloid Peptide with Single Curcuminoids

A broad biophysical analysis was performed to investigate the molecular basis of the neuroprotective action of Curcuma longa extracts in Alzheimer's disease. By combining circular dichroism and electron paramagnetic resonance experiments with molecular modeling calculations, the minor components of Curcuma longa extracts, such as demethoxycurcumin (2, DMC), bisdemethoxycurcumin (3, BDMC) and cyclocurcumin (4, CYC), were analyzed in a membrane environment mimicking the phospholipid bilayer. Our study provides the first evidence on the relative role of single curcuminoids interacting with Aβ-peptide. When the CYC and curcumin metabolite tetrahydrocurcumin (5, THC) were inserted into an anionic lipid solution, a significant modification of the Aβ CD curves was detected. These data were implemented by EPR experiments, demonstrating that CYC reaches the inner part of the bilayer, while the other curcuminoids are localized close to the membrane interface. Computational studies provided a model for the curcuminoid-Aβ interaction, highlighting the importance of a constrained "semi-folded" conformation to interact with Aβ analogously to the pattern observed in α-helical coiled-coil peptide structures. This combined approach led to a better understanding of the intriguing in vitro and in vivo activity of curcuminoids as anti-Alzheimer agents, paving a new path for the rational design of optimized druggable analogues

Methodological Guidelines for Engineering Self-organization and Emergence

The ASCENS project deals with the design and development of complex self-adaptive systems, where self-organization is one of the possible means by which to achieve self-adaptation. However, to support the development of self-organising systems, one has to extensively re-situate their engineering from a software architectures and requirements point of view. In particular, in this chapter, we highlight the importance of the decomposition in components to go from the problem to the engineered solution. This leads us to explain and rationalise the following architectural strategy: designing by following the problem organisation. We discuss architectural advantages for development and documentation, and its coherence with existing methodological approaches to self-organisation, and we illustrate the approach with an example on the area of swarm robotics