The expression of molecular dissymmetry in crystal form has been studied since Pasteur correlated macroscopic and microscopic chirality by measuring the optical activity of solutions of enantiomorphous tartrate salt crystals. Here, we show a direct correlation between enantiomorphous metal-organic framework (MOF) crystals and the chirality of the molecular structure. The geometry of the habits is correlated with single-crystal optical activity along the accessible low-symmetry directions. Weak X-ray scattering from small crystals was consistent with a hexagonal, enantiomorphous space group. However, the heterochirality of the mirror image forms could not be established with X-rays, necessitating a different approach. The optical circular birefringence of the enantiomorphs as evidenced by chiroptical imaging with a complete polarimetric microscope, was used to correlate optical and morphological chirality.

Paracetamol crystalline form III grows just above the glass transition temperature as aggressively twisted fibers that thicken in successive stages, forming complex assemblies. The growth direction is parallel to a glide plane leading to heterochiral crystals. These enantiomorphs are not Pasteur-like polyhedra with hemihedral facets that are the tell-tale signs of dissymmetric form; here every surface is dissymmetric. The chiroptical properties of the heterochiral forms are assayed as they evolve directly in the solid state using complete polarimetry.

Molnupiravir, a small molecule active pharmaceutical ingredient developed through a partnership between Merck and Ridgeback Biotherapeutics, was shown to be efficacious for the treatment of patients with COVID-19. Early in development it was discovered that molnupiravir can exist in two structurally similar polymorphic states. Detailed in this presentation will be the exhaustive studies to elucidate the structures of these polymorphs including single crystal X-ray diffraction, structure solution from high resolution powder diffraction, and crystal structure prediction was leveraged. Further discussion around the structural insights gained and how they relate to the physical properties of the two polymorphs will also be discussed. This knowledge informed and guided the control strategy to support the development of a large-scale manufacturing route suitable to meet the high material demands and to get this drug into the hands of patients around the world.

Gene therapy holds great potential for treating neurological disorders, but its implementation is limited by the challenge of developing a safe and effective delivery method to the central nervous system (CNS). Red blood cell-derived extracellular vesicles (RBCEVs) have the potential to address these challenges due to their non-immunogenicity, non-cytotoxicity, ability to be redosed, and suitability for nucleic acid loading. In this study, we demonstrate the efficacy and safety of RBCEV-mediated nucleic acid delivery to the CNS. We found that RBCEVs administered through intrathecal injection are widely distributed across the CNS and efficiently taken up by neuronal cells. Delivery of RBCEVs loaded with GFP-encoding plasmids results in GFP expression in neurons. Our data also highlight the potential of RBCEVs to deliver plasmids encoding secretory proteins, resulting in protein secretion within the cerebrospinal fluid. Furthermore, experiments conducted in both mouse and non-human primate models indicate that intrathecal injection of plasmid-loaded RBCEVs do not lead to any systemic or local acute toxicity. In summary, our findings illustrate the potential of the RBCEV-based platform as a viable and safe approach for nucleic acid delivery to the CNS, facilitating further development of gene therapy for neurological disorders.

Interleukin-12 (IL-12) holds significant potential in cancer therapy; however, its clinical applicability is hindered by dose-limiting toxicity. Delivery of the IL-12 gene directly to tumours for constitutive IL-12 expression is a possible strategy to enhance its effectiveness while minimizing systemic toxicity. In this study, we investigate the potential of red blood cell-derived extracellular vesicles (RBCEVs) as a carrier for Il-12 plasmid delivery. We demonstrate that RBCEVs can be loaded with minicircle plasmid encoding IL-12 and delivered to MB49 bladder cancer cells for IL-12 expression. The expression of transgenes from minicircles was significantly higher than from the parental plasmids. RBCEV-mediated IL-12 expression stimulated immune responses in mouse splenocytes. Intratumoral delivery of Il-12 plasmid-loaded RBCEVs suppressed bladder cancer tumour growth, stimulated immune responses and promoted immune cell infiltration. In conclusion, our study demonstrates the promising potential of RBCEVs as an effective, safe and redosable nucleic acid drug delivery platform for IL-12.

Disorder is a common feature of molecular crystals that complicates determination of structures and can potentially affect electric and mechanical properties. Suppression of disorder is observed in otherwise severely disordered benzamide and thiobenzamide crystals by substituting hydrogen with fluorine in the ortho-position of the phenyl ring. Fluorine occupancies of 20-30% are sufficient to suppress disorder without changing the packing motif. Crystal structure prediction calculations reveal a much denser lattice energy landscape for benzamide compared to 2-fluorobenzamide, suggesting that fluorine substitution makes disorder less likely.

Molnupiravir is a small-molecule active pharmaceutical ingredient (API) prodrug of a nucleoside analog that was demonstrated to be efficacious for the treatment of patients with COVID-19. Early in the pandemic, Merck & Co. Inc. partnered with Ridgeback Biotherapeutics to accelerate the development of a manufacturing process for the drug in anticipation of high global demand for the treatment. It was essential to quickly establish a robust manufacturing process, as well as a rigorous physical attribute control strategy, to enable rapid delivery of metric tons of molnupiravir. Given the drug load of >50% (w/w) API in the formulation, there was high potential for the physical attributes to have a strong effect on drug product performance. Molnupiravir can also exist as multiple polymorphs and has the potential for wide variations in particle size. To address these challenges, we performed extensive derisking of these attributes with respect to the impact on drug product performance and were ultimately able to demonstrate the acceptability of a wide range of API physical attributes. In parallel, we strategically designed a scalable crystallization process that consistently delivered drug substance within our derisked range of attributes, across multiple manufacturing sites and scales. Thus, we were able to demonstrate that the API's physical attributes did not affect the drug product's critical quality attributes or therapeutic efficacy, giving our multiple manufacturing sites greater flexibility to deliver metric tons of molnupiravir to patients in need.

The development and mechanistic investigation of a nickel-catalyzed sulfonylation of aryl bromides is disclosed. The reaction proceeds in good yields for a variety of substrates and utilizes an inexpensive, stench-free, inorganic sulfur salt (K2 S2 O5 ) as a uniquely effective SO2 surrogate. The active oxidative addition complex was synthesized, isolated, and fully characterized by a combination of NMR spectroscopy and X-ray crystallography analysis. The use of the isolated oxidative addition complex in both stoichiometric and catalytic reactions revealed that SO2 insertion occurs via dissolved SO2 , likely released upon thermal decomposition of K2 S2 O5 . Key to the success of the reaction is the role of K2 S2 O5 as a reservoir of SO2 that is slowly released, thus preventing catalyst poisoning.

This article reports a rare example of the crystallization of a cocrystal of an organic molecule with its epimer. In this case, belzutifan, a novel treatment for von Hippel–Lindau (VHL) disease-associated renal cell carcinoma (RCC), crystallizes as a 1:1 cocrystal with one of its epimers (inversion of stereochemistry at the hydroxyl position). This observation is of particular importance to controlling the purity of the API in the commercial manufacturing process. After the discovery of this cocrystal, the crystalline structure was determined through a combination of crystal structure prediction (CSP) and powder X-ray diffraction followed by single-crystal X-ray diffraction structure determination. The only lattice interaction that exists between the two epimers is a π–π stacking arrangement created by the alternating fluorobenzonitrile aryl groups of each epimer. The formation of this complex, while unexpected, is a reminder that unexplored crystal forms can pose a significant risk to the robustness of chemical manufacturing processes. At present, the cost of leveraging CSP tools across the entirety of a synthetic process is significant. However, discoveries such as the belzutifan:hydroxy epimer cocrystal highlight why current investments in in silico tools are needed and justify expanding their use to de-risk commercial synthetic routes to expedite the development of life-saving medications.

Crystal twisting introduces optical activity to organic semiconducting films of centrosymmetric tetrathiafulvalene.

The advent of novel therapeutics in recent years has urged the need for a safe, non-immunogenic drug delivery vector capable of delivering therapeutic payloads specifically to diseased cells, thereby increasing therapeutic efficacy and reducing side effects. Extracellular vesicles (EVs) have garnered attention in recent years as a potentially ideal vector for drug delivery, taking into account their intrinsic ability to transfer bioactive cargo to recipient cells and their biocompatible nature. However, natural EVs are limited in their therapeutic potential and many challenges need to be overcome before engineered EVs satisfy the levels of efficiency, stability, safety and biocompatibility required for therapeutic use. Here, we demonstrate that an enzyme-mediated surface functionalization method in combination with streptavidin-mediated conjugation results in efficient surface functionalization of EVs. Surface functionalization using the above methods permits the stable and biocompatible conjugation of peptides, single domain antibodies and monoclonal antibodies at high copy number on the EV surface. Functionalized EVs demonstrated increased accumulation in target cells expressing common cancer associated markers such as CXCR4, EGFR and EpCAM both in vitro and in vivo. The functionality of this approach was further highlighted by the ability of targeting EVs to specifically deliver therapeutic antisense oligonucleotides to a metastatic breast tumor model, resulting in increased knockdown of a targeted oncogenic microRNA and improved metastasis suppression. The method was also used to equip EVs with a bifunctional peptide that targets EVs to leukemia cells and induces apoptosis, leading to leukemia suppression. Moreover, we conducted extensive testing to verify the biocompatibility, and safety of engineered EVs for therapeutic use, suggesting that surface modified EVs can be used for repeated dose treatment with no detectable adverse effects. This modular, biocompatible method of EV engineering offers a promising avenue for the targeted delivery of a range of therapeutics while addressing some of the safety concerns associated with EV-based drug delivery.

Although the crystal structures of small-molecule compounds are often determined from single-crystal X-ray diffraction (scXRD), recent advances in three-dimensional electron diffraction (3DED) and crystal structure prediction (CSP) methods promise to expand the structure elucidation toolbox available to the crystallographer. Herein, a comparative assessment of scXRD, 3DED, and CSP in combination with powder X-ray diffraction is carried out on two former drug candidate compounds and a multicomponent crystal of a key building block in the synthesis of gefapixant citrate.

Cancer is a disease that evolves continuously with unpredictable outcomes. Although conventional chemotherapy can display significant antitumor effects, the lack of specificity and poor bioavailability remain major concerns in cancer therapy. Moreover, with the advent of novel anti-cancer gene therapies, there is an urgent need for drug delivery vectors capable of bypassing cellular barriers and efficiently transferring therapeutic cargo to recipient cells. A number of drug delivery systems have been proposed to overcome these limitations, but their successful clinical translation has been hampered by the onset of unexpected side effects and associated toxicities. The application of extracellular vesicles (EVs), a class of naturally released, cell-derived particles, as drug delivery vectors presents a breakthrough in nanomedicine, taking into account their biocompatibility and natural role in intercellular communication. Combining the advantageous intrinsic properties of EVs with surface functionalization and the encapsulation of drugs allows for a new class of engineered EVs that serve as effective therapeutic carriers. Here, we describe the various successful approaches involving the application of engineered EVs as bio-derived drug delivery vectors in cancer therapy. The latest and most effective strategies of engineering EVs to improve drug loading, stealth properties and tumour targeting capabilities of EVs are debated. Finally, current obstacles and future perspectives of smart engineered EVs are discussed.

During large-scale crystallization of the ethyl ester (EE) starting material of Doravirine (MK-1439) (Huang et al. ACS Infectious Dis. 2020, 6, 64-73) four out of nine batches exhibited unique infrared spectra upon release testing and atypical powder X-ray diffraction (PXRD) patterns not conforming to the target crystalline phase, Form 1. This work presents the investigations triggered within MSD's laboratories on the polymorphism of EE and the strategy employed for identifying the nature of the form impurity and understanding its thermodynamic relationship with Form 1. The team's response for avoiding its reoccurrence through a bullet-proofed crystallization process consistently delivering Form 1 is also presented. The form impurity was identified as a new polymorph of EE, Form 2, which is revealed to have an enantiotropic relationship with Form 1 with a transition temperature at ca. 0-5 degrees C. Form 2 is thermodynamically favored above this transition temperature and at ambient conditions. A combination of X-ray powder diffraction and crystal structure prediction was used to solve the crystal structure of Form 2. The spontaneous nucleation of both physical forms and their competitive growth in ethanol (EtOH)/water revealed that (1) high supersaturation leads to primary nucleation of Form 2 below the transition temperature and is avoided by slow cooling rates; (2) the desired kinetic Form 1 grows much faster over Form 2, even in the presence of Form 2 particles at temperatures <= 25 degrees C; and (3) Form 1 to Form 2 rapid turnover occurs at temperatures >= 30 degrees C. As a result, a Form 1 seeded crystallization was developed with a controlled cooling rate and antisolvent addition followed by a final aging at low temperature. The process was implemented at multiple scales to maximize productivity through consistent delivery of Form 1 and avoidance of Form 2 that exhibits poor filtration performance.

Electronic skins equip robots and biomedical devices with intuitive skin‐like sensitivity. Performance‐driven design of electronic skins is a critical need for electronic or biomedical applications. Prior research primarily focuses on investigating effects of microstructures on sensor performance at low pressure ranges. However, having predictive and tunable electro–mechanical responses across an extensive pressure range (>100 kPa) is paramount. Here, the authors propose a system that virtually customizes micropyramids for e‐skin sensors. The associations between geometry parameters, material properties, and single‐pyramid performance are systematically explored via numerical simulations, empirical characterizations, and analytical solutions. These experimentally validated models allow for the determination of the sensor parameters for the desired performance. An augmented reality interface system for surgery skills training by optimizing sensitivities that match varying tissue stiffnesses is further demonstrated. The platform enables greater effectiveness in rapidly iterating and designing micropyramidal e‐skin for applications in augmented reality interfaces, robotics, and telehealthcare.

Singlet fission (k(SF)) and excimer formation (k(EXC)) rate constants along with other photophysical properties of thin solid layers of 1,3-diphenylisobenzofuran and 11 of its fluorinated derivatives have been determined. The molecular properties of these compounds are similar, but their crystal packing varies widely. Most of them undergo singlet fission whereas excitation in others is trapped in excimers. The trend in rate constants k(SF) agrees qualitatively with results of calculations by a simplified version of the frontier orbital model for a molecular pair. The main shortcoming of the model is discussed.