-nitrosamines are widespread cancerogenic compounds in human environment, including water, tobacco products, food, and medicinal products. Their presence in pharmaceuticals has recently led to several recalls of important medicines from the market, and strict controls and tight limits of -nitrosamines are now required. Analytical determination of -nitrosamines is expensive, laborious, and time-inefficient making development of simpler and faster techniques for their detection crucial.
View Article and Find Full Text PDFGlasdegib is a recently approved drug for the treatment of acute myeloid leukemia. It is formulated and marketed in monomaleate salt form. In our investigation, we were able to prepare a glasdegib dimaleate form, which could, in theory, exist in double-salt form or as a mixture of salt and co-crystal species.
View Article and Find Full Text PDFThis work describes the first preparation and application of primary trifluoroborate-iminiums (pTIMs) as a new, easily accessible and valuable class of organoboron derivatives. An array of structurally diverse pTIMs was prepared from potassium acyltrifluoroborates in excellent yields. Highly efficient and enantioselective [(,)-TethTsDpen-RuCl] complex-catalyzed hydrogenation of pTIMs provided direct access to chiral primary trifluoroborate-ammoniums (pTAMs).
View Article and Find Full Text PDFCabotegravir is one of the newly approved human immunodeficiency virus (HIV) integrase enzyme inhibitors used for the prevention and treatment of HIV infection. It is the first approved long-acting injectable antiretroviral therapy for HIV and is also very effective in combination with rilpivirine, a non-nucleoside reverse transcriptase inhibitor. Therefore, future drug development involving cabotegravir can be expected.
View Article and Find Full Text PDFA concise six-step asymmetric synthesis of nearly enantiomerically pure ramelteon was developed from a monocyclic precursor with a 17% overall yield and a 97% ee in the asymmetric step. The synthetically challenging tricyclic 1,6,7,8-tetrahydro-2-indeno[5,4-]furan core of ramelteon was assembled by using Ir-catalyzed -vinylation and Rh-catalyzed vinyl ether annulation through directed C-H bond activation, while the chirality was introduced with enantioselective reduction of an α,β-unsaturated nitrile moiety under hydrosilylation conditions using a Cu/Walphos type catalyst. The presented methodology represents the shortest synthetic approach to ramelteon.
View Article and Find Full Text PDFCabotegravir is a novel human immunodeficiency virus integrase enzyme inhibitor used for prevention and treatment of HIV infection. The combinational final dosage form, as extended release injection suspension in combination with rilpivirine and as cabotegravir tablets (for lead-in therapy), was recently approved in Canada, EU and in USA and is currently seeking approval also in other countries. The subject of this investigation was to study the degradation of cabotegravir under different stress conditions as per the International Council for Harmonization (ICH) guidelines.
View Article and Find Full Text PDFThe most common types of acylboranes are acyltrifluoroborates, acyl MIDA-boronates, and monofluoroacylboronates. Because of the increasing importance of these compounds in the past decade, we highlight the recently reported synthetic strategies to access acylboranes. In addition, an expanding array of their applications has been discovered, based on either the ability of acylboranes to enter rapid amide-forming ligations or the retained ketone-like character of the carbonyl group.
View Article and Find Full Text PDFVenetoclax is an emerging drug for the treatment of various types of blood cancers. It was first approved in 2016 for the treatment of relapsed and refractory chronic lymphocytic leukemia. Later, the indications expanded, and multiple research as well as clinical studies are still conducted involving venetoclax.
View Article and Find Full Text PDFVenetoclax is an orally bioavailable, B-cell lymphoma-2 (BCL-2) selective inhibitor, used for the treatment of various types of blood cancers, such as chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL). In this study we investigated the degradation of venetoclax under various stress conditions including acidic, basic, oxidative, photolytic and thermolytic conditions. We isolated and identified six of its main degradation products produced in forced degradation studies.
View Article and Find Full Text PDFThis article presents the development of a reversed-phase ultra-high-performance liquid chromatographic method for determining process-related impurities in ropinirole hydrochloride drug substance applying the analytical quality by design approach. The current pharmacopeial method suffers from selectivity issues due to two coelutions of two pairs of impurities. The development of a new method began with preliminary experiments, based on which the Acquity UPLC BEH C8 was selected as the most appropriate column.
View Article and Find Full Text PDFTenofovir alafenamide fumarate (TAF) is the newest prodrug of tenofovir that constitutes several drug products used for the treatment of HIV/AIDS. Although the solid-state properties of its predecessor tenofovir disoproxil fumarate have been investigated and described in the literature, there are no data in the scientific literature on the solid state properties of TAF. In our report, we describe the preparation of two novel polymorphs II and III of tenofovir alafenamide monofumarate (TA MF2 and TA MF3).
View Article and Find Full Text PDFd-cycloserine is a broad-spectrum antibiotic that is currently being used as a secondary choice in the treatment of tuberculosis. In recent years, it has become more popular, due to its effect on the nervous system. In this current study, we provide evidence that The International Pharmacopoeia HPLC-UV method for d-cycloserine impurity profiling is not repeatable due to the variable response of cycloserine dimer, one of d-cycloserine impurities.
View Article and Find Full Text PDFVarious organic impurities (starting materials, reagents, intermediates, degradation products, by-products, and side products) could be present in active pharmaceutical ingredients affecting their qualities, safeties, and efficacies. Herein, we present the efficient syntheses of two United States Pharmacopeia impurities of an antidiabetic drug sitagliptin, a potent and orally active dipeptidyl peptidase IV inhibitor: 3-desamino-2,3-dehydrositagliptin and 3-desamino-3,4-dehydrositagliptin. Our three-step synthetic approach is based on the efficient cobalt-catalyzed cross-coupling reaction of 1-bromo-2,4,5-trifluorobenzene and methyl 4-bromocrotonate in the first step, followed by hydrolysis of corresponding ester with 3 M HCl to ()-(2,4,5-trifluorophenyl)but-2-enoic acid in high overall yield, whereas the reaction with 3 M NaOH resulted in the carbon-carbon double bond regio-isomerization and hydrolysis to give the ()-(2,4,5-trifluorophenyl)but-3-enoic acid in 92% yield.
View Article and Find Full Text PDFThis article presents the development of a reversed-phase (RP) high-performance liquid chromatographic (HPLC) method for determination of process-related impurities in a celecoxib drug substance following Analytical Quality by Design (AQbD) principles. The method from European Pharmacopeia (EP) for celecoxib drug substance does not sufficiently separate celecoxib from its EP impurity B because the system suitability criterion is not achieved (resolution NLT 1.8).
View Article and Find Full Text PDF: Studies presented in the patent applications demonstrate that a new integrase strand transfer inhibitor cabotegravir might be used as long-acting antiretroviral formulation or delivery system that reduces dosing frequency and may therefore increase adherence and thus pre-exposure prophylaxis (PrEP) and treatment efficacy against HIV. As announced in 2019, the developer ViiV Healthcare seeks US and EU approval of long-acting, injectable HIV treatment.: This review covers all the patent applications published until October 2019 with cabotegravir in the examples or claim section of the patent application document.
View Article and Find Full Text PDFReactive impurities originating from excipients can cause drug stability issues, even at trace amounts. When produced during final dosage form storage, they are especially hard to control, and often, factors inducing their formation remain unidentified. Oxidative degradation dependent formation of formaldehyde and formic acid is responsible for methylation and -formylation of amine-moiety-containing drug substances.
View Article and Find Full Text PDFDrug substance degradation kinetics in solid dosage forms is rarely mechanistically modeled due to several potential micro-environmental and manufacturing related effects that need to be integrated into rate laws. The aim of our work was to construct a model capable of predicting individual degradation product concentrations, taking into account also formulation composition parameters. A comprehensive study was done on active film-coated tablets, manufactured by layering of the drug substance, a primary amine compound saxagliptin, onto inert tablet cores.
View Article and Find Full Text PDFIntroduction: Studies presented in patents show that a novel chemotherapeutic agent, venetoclax, might be useful in additional therapeutic indications. Venetoclax is approved in America for the treatment of patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). Venetoclax selectively inhibits the B-cell lymphoma-2 (Bcl-2) protein, an anti-apoptotic protein that can be overexpressed in most B-cell lymphoid malignancies.
View Article and Find Full Text PDFWe have elaborated a one-pot three-component assembly of trityl olmesartan medoxomil starting from commercially available ethyl 4-(2-hydroxypropan-2-yl)-2-propyl-1H-imidazole-5-carboxylate, 5-(4'-(bromomethyl)-[1,1'-biphenyl]-2-yl)-1-trityl-1H-tetrazole and 4-(chloromethyl)-5-methyl-1,3-dioxol-2-one intermediates. The developed and optimized one-pot process provides 72-75% yield of trityl olmesartan medoxomil over three steps, which represents in average ca. 90% yield per synthetic step, on a 300 g scale.
View Article and Find Full Text PDFWe have elaborated a two-step catalytic approach to nafoxidine, a key precursor to lasofoxifene. Firstly, an efficient α-arylation of 6-methoxy-3,4-dihydronaphthalen-1(2H)-one with chlorobenzene was developed, which operates at low 0.1 mol% Pd-132 catalyst loading in the presence of 1.
View Article and Find Full Text PDFA six-step synthetic route from 4-chloro-2-methylaniline to 5-chloro-2-(cyclobut-1-en-1-yl)-3-(trifluoromethyl)-1H-indole (1) has been reported. Compound 1a is a key impurity of reverse transcriptase inhibitor efavirenz, an important anti-HIV/AIDS drug. Synthetic challenges, dead ends, and detours are discussed.
View Article and Find Full Text PDFSarcosine was discovered to be an excellent ligand for cobalt-catalyzed carbon-carbon cross-coupling of Grignard reagents with allylic and vinylic bromides. The Co(II)/sarcosine catalytic system is shown to perform efficiently when phenyl and benzyl Grignards are coupled with alkenyl bromides. Notably, previously unachievable Co-catalyzed coupling of allylic bromides with Grignards to linearly coupled α-products was also realized with Co(II)/sarcosine catalyst.
View Article and Find Full Text PDFSuper-statins are synthetic inhibitors of 3-hydroxy-3-methylglutaryl-coenzyme A reductase, which is the rate-limiting enzyme responsible for the biosynthesis of cholesterol. All of the super-statins with a C=C double bond spacer between the heterocyclic and the dihydroxycarboxylic moiety that are currently on the market exist as E-isomers. To extend the understanding of conformational and thermodynamic preferences of Z-isomeric super-statin analogues, this study focused on analyzing pitavastatin and its lactonized derivatives via NMR spectroscopy and ab initio calculations.
View Article and Find Full Text PDFEmploying DERA (2-deoxyribose-5-phosphate aldolase), we developed the first whole-cell biotransformation process for production of chiral lactol intermediates useful for synthesis of optically pure super-statins such as rosuvastatin and pitavastatin. Herein, we report the development of a fed-batch, high-density fermentation with Escherichia coli BL21 (DE3) overexpressing the native E. coli deoC gene.
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