Practical Synthesis of 7-Bromo-4-chloro-1H-indazol-3-amine: An Important Intermediate to Lenacapavir.

7-Bromo-4-chloro-1H-indazol-3-amine is a heterocyclic fragment used in the synthesis of Lenacapavir, a potent capsid inhibitor for the treatment of HIV-1 infections. In this manuscript, we describe a new approach to synthesizing 7-bromo-4-chloro-1H-indazol-3-amine from inexpensive 2,6-dichlorobenzonitrile. This synthetic method utilizes a two-step sequence including regioselective bromination and heterocycle formation with hydrazine to give the desired product in an overall isolated yield of 38-45%. The new protocol has been successfully demonstrated on hundred-gram scales without the need for column chromatography purification. This new synthesis provides a potential economical route to the large-scale production of this heterocyclic fragment of Lenacapavir.

Iterative Regression of Corrective Baselines (IRCB): A New Model for Quantitative Spectroscopy.

In this work, a new model with broad utility for quantitative spectroscopy development is reported. A primary objective of this work is to create a novel modeling procedure that may allow for higher automation of the model development process. The fundamental concept is simple yet powerful even for complex spectra and is employed with no additional preprocessing. This approach is applicable for several types of spectroscopic data to develop regression models that have similar or greater quality than the current methods. The key modeling steps are a matrix transformation and subsequent feature selection process that are collectively referred to as iterative regression of corrective baselines (IRCB). The transformed matrix (Xtransform) is a linearized form of the original X data set. Features from Xtransform that are predictive of Y can be ranked and selected by ordinary least-squares regression. The best features (rows of Xtransform) are linear depictions of Y that can be utilized to develop regression models with several machine learning models. The IRCB workflow is first detailed by using a case study of Fourier transform infrared (FTIR) spectroscopy for prepared solutions of a three-component mixture. Next, IRCB is applied and compared to benchmark results for the 2006 "Chimiométrie" near-infrared spectroscopy (NIR) soil composition challenge and Raman measurements of a simulated nuclear waste slurry.

An Automated Continuous Synthesis and Isolation for the Scalable Production of Aryl Sulfonyl Chlorides.

In this work, a continuous system to produce multi-hundred-gram quantities of aryl sulfonyl chlorides is described. The scheme employs multiple continuous stirred-tank reactors (CSTRs) and a continuous filtration system and incorporates an automated process control scheme. The experimental process outlined is intended to safely produce the desired sulfonyl chloride at laboratory scale. Suitable reaction conditions were first determined using a batch-chemistry design of experiments (DOE) and several isolation methods. The hazards and incompatibilities of the heated chlorosulfonic acid reaction mixture were addressed by careful equipment selection, process monitoring, and automation. The approximations of the CSTR fill levels and pumping performance were measured by real-time data from gravimetric balances, ultimately leading to the incorporation of feedback controllers. The introduction of process automation demonstrated in this work resulted in significant improvements in process setpoint consistency, reliability, and spacetime yield, as demonstrated in medium- and large-scale continuous manufacturing runs.

Encapsulation of a highly hydrophilic drug in polymeric particles: A comparative study of batch and microfluidic processes.

The objective of this work was to investigate the effect of microfluidics on the quality attributes of metformin hydrochloride-loaded poly lactic-co-glycolic acid polymeric particles (MFH-PLGA PPs) when compared to a traditional double emulsion batch method. The relationship of encapsulation and loading efficiencies, yield %, particle size, surface morphology, and release profile with process and formulation variables were determined using design of experiments (DoE). The effects of the dispersal method of the primary (sonication vs. vortex) or secondary emulsion (microfluidics vs. batch), polyvinyl alcohol concentration (PVA), and drug to polymer ratio were investigated. The PPs' size was impacted by both the PVA concentration and the type of primary and secondary emulsion dispersion methods. Microfluidics significantly increased the PPs' yield %, particle size, encapsulation, and loading efficiencies. The higher loaded microfluidic-based PPs had more burst release, following first-order release kinetics when compared to the lower loaded batch-based particles, which followed the Korsmeyer-Peppas model for release kinetics. Microfluidic-based PPs exhibited a smooth, porous, more uniform, and larger particle size with hollow structure than the batch-based PPs with a matrix-like structure. In conclusion, we have elucidated the effect of microfluidics on the quality attributes of MFH-PLGA PPs and their comparison to the traditional batch technique.

Identification of 2,2-Dimethylbutanoic Acid (HST5040), a Clinical Development Candidate for the Treatment of Propionic Acidemia and Methylmalonic Acidemia.

Propionic acidemia (PA) and methylmalonic acidemia (MMA) are rare autosomal recessive disorders of propionyl-CoA (P-CoA) catabolism, caused by a deficiency in the enzymes P-CoA carboxylase and methylmalonyl-CoA (M-CoA) mutase, respectively. PA and MMA are classified as intoxication-type inborn errors of metabolism because the intramitochondrial accumulation of P-CoA, M-CoA, and other metabolites results in secondary inhibition of multiple pathways of intermediary metabolism, leading to organ dysfunction and failure. Herein, we describe the structure-activity relationships of a series of short-chain carboxylic acids which reduce disease-related metabolites in PA and MMA primary hepatocyte disease models. These studies culminated in the identification of 2,2-dimethylbutanoic acid (10, HST5040) as a clinical candidate for the treatment of PA and MMA. Additionally, we describe the in vitro and in vivo absorption, distribution, metabolism, and excretion profile of HST5040, data from preclinical studies, and the synthesis of the sodium salt of HST5040 for clinical trials.

Self-Assembly of pH-Labile Polymer Nanoparticles for Paclitaxel Prodrug Delivery: Formulation, Characterization, and Evaluation.

The efficacy of paclitaxel (PTX) is limited due to its poor solubility, poor bioavailability, and acquired drug resistance mechanisms. Designing paclitaxel prodrugs can improve its anticancer activity and enable formulation of nanoparticles. Overall, the aim of this work is to improve the potency of paclitaxel with prodrug synthesis, nanoparticle formation, and synergistic formulation with lapatinib. Specifically, we improve potency of paclitaxel by conjugating it to α-tocopherol (vitamin E) to produce a hydrophobic prodrug (Pro); this increase in potency is indicated by the 8-fold decrease in half maximal inhibitory concentration (IC50) concentration in ovarian cancer cell line, OVCA-432, used as a model system. The efficacy of the paclitaxel prodrug was further enhanced by encapsulation into pH-labile nanoparticles using Flash NanoPrecipitation (FNP), a rapid, polymer directed self-assembly method. There was an 1100-fold decrease in IC50 concentration upon formulating the prodrug into nanoparticles. Notably, the prodrug formulations were 5-fold more potent than paclitaxel nanoparticles. Finally, the cytotoxic effects were further enhanced by co-encapsulating the prodrug with lapatinib (LAP). Formulating the drug combination resulted in synergistic interactions as indicated by the combination index (CI) of 0.51. Overall, these results demonstrate this prodrug combined with nanoparticle formulation and combination therapy is a promising approach for enhancing paclitaxel potency.

3D Printing of Metformin HCl PVA Tablets by Fused Deposition Modeling: Drug Loading, Tablet Design, and Dissolution Studies.

The main aim of this work was to 3D print metformin HCl-loaded PVA (ML-PVA) tablets by fused deposition modeling. A modified solvent diffusion approach was used to improve drug loading. PVA filaments were placed in metformin HCl solution in ethanol containing low water content (10%(v/v)) to enhance the drug's solubility. The physicochemical properties of ML-PVA filaments were characterized before and after printing. Lastly, ML-PVA filaments were printed into channeled tablet designs to increase their surface area available for dissolution. The loading of metformin HCl onto PVA filament has significantly increased from 0.08 ± 0.02% in metformin HCl solution in absolute ethanol to 1.40 ± 0.02% in ethanol-water (9:1). The IR spectra of PVA filament soaked in ethanol-water depicted higher peak intensity at 1138 cm-1, indicating higher degree of crystallinity. Thermal analysis of the soaked PVA filaments showed higher melting enthalpies yet lower melting temperature (Tm) compared to unprocessed PVA. ML-PVA filaments were successfully printed into round-channeled tablets (10% infill) with higher surface area and area/volume ratios compared with the solid ones. The inclusion of channels in the tablet design modified their printing pattern causing an unexpected increase in their mass. The dissolution profiles of ML-PVA tablets were mainly dependent on their area/mass ratios. Our results show a simple approach to increase metformin HCl loading onto PVA and reveal the significance of tablet design, infill percentage, and printing pattern as they dictate the area, volume, and the mass of the tablet which impact its dissolution rate.

Continuous flow synthesis of a pharmaceutical intermediate: a computational fluid dynamics approach.

Continuous flow chemistry has the potential to greatly improve efficiency in the synthesis of active pharmaceutical ingredients (APIs); however, the optimization of these processes can be complicated by a large number of variables affecting reaction success. In this work, a screening design of experiments was used to compare computational fluid dynamics (CFD) simulations with experimental results. CFD simulations and experimental results both identified the reactor residence time and reactor temperature as the most significant factors affecting product yield for this reaction within the studied design space. A point-to-point comparison of the results showed absolute differences in product yield as low as 2.4% yield at low residence times and up to 19.1% yield at high residence times with strong correlation between predicted and experimental percent yields. CFD was found to underestimate the product yields at low residence times and overestimate at higher residence times. The correlation in predicted product yield and the agreement in identifying significant factors in reaction performance reveals the utility of CFD as a valuable tool in the design of continuous flow tube reactors with significantly reduced experimentation.

7-Step Flow Synthesis of the HIV Integrase Inhibitor Dolutegravir.

Dolutegravir (DTG), an important active pharmaceutical ingredient (API) used in combination therapy for the treatment of HIV, has been synthesized in continuous flow. By adapting the reported GlaxoSmithKline process chemistry batch route for Cabotegravir, DTG was produced in 4.5 h in sequential flow operations from commercially available materials. Key features of the synthesis include rapid manufacturing time for pyridone formation, one-step direct amidation of a functionalized pyridone, and telescoping of multiple steps to avoid isolation of intermediates and enable for greater throughput.

Efficient synthesis of an adenosine A2a agonist: glycosylation of 2-haloadenines and an N2-alkyl-6-chloroguanine.

A convergent synthesis of adenosine A2a agonist 1 in the form of its maleate salt 2 was achieved. The key step in this approach was the highly selective 9beta-glycosylation reaction between 2-haloadenines or an N(2)-alkyl-6-chloroguanine and a D-ribose derivative containing a 2-ethyltetrazolyl moiety. Glycosylations of other purine derivatives were also examined, and the methods developed provide efficient access to a variety of adenosine analogues such as 2-alkylaminoadenosines, an attractive class of compounds with antiinflammatory activity.