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Resumen La dopamina 1, está implicada en trastornos neurodegenerativos que afectan al sistema nervioso central (SNC) tales como la enfermedad de Parkinson, entre otros. Aunque no se dispone aún de ningún fármaco capaz de prevenir, detener o curar la progresión de estas enfermedades, son numerosos los compuestos que han sido diseñados, sintetizados y evaluados farmacológicamente, que han aportado las generalizaciones farmacofóricas del receptor dopaminérgico, necesarias para la búsqueda de un fármaco capaz de mejorar o curar estas patologías. Los derivados 2-aminoindano-N-aralquílicos han mostrado tener actividad selectiva en el sistema dopaminérgico central, de modo tal que los compuestos clorhidratos de N-[(2,4-diclorofenil)-1-metil- etil]-2-aminoindano 2 y N-[(3,4-diclorofenil)-1-metil-etil]-2-aminoindano 3 demostraron tener actividad agonística mediada por mecanismos dopaminérgicos centrales. Con el propósito de contribuir en la búsqueda de nuevos fármacos que permitan restablecer la homeostasis de la transmisión dopaminérgica en la enfermedad de Parkinson, el compuesto N-2,6-dicloro-aralquil-2-aminoindano 4 fue diseñado a través de estrategias de la química medicinal, que contienen las aproximaciones farmacofóricas de los profármacos. La evaluación farmacológica del compuesto 4, en la conducta estereotipada en ratas macho de la cepa Sprague Dawley, demostró tener actividad agonística a través de la activación de los mecanismos dopaminérgicos centrales y mostró mayor selectividad en las respuestas de conductas estereotipadas propias de los ganglios basales sobre las respuestas conductuales propias de las estructuras límbicas.
Abstract Dopamine 1 is involved in neurodegenerative disorders affecting the central nervous system (CNS), such as Parkinson's disease. Despite the absence of some available drugs capable of preventing, stopping or curing the progression of such diseases, there are numerous compounds designed, synthesized, and pharmacologically tested which give rise to pharmacophoric generalizations about the dopaminergic receptor required for the search of a drug able to improve or cure those pathologies. N-aralkyl-2-aminoindane derivatives have shown selective activity in the central dopaminergic system. Both the N-[(2,4-dichlorophenyl)-1-methyl-ethyl]-2-aminoindane hydrochloride 2 and N-[(3,4-dichlorophenyl)-1-methyl-ethyl]-2-aminoindane hydrochloride 3 showed an agonistic activity mediated by central dopaminergic mechanisms. To contribute to the search of new drugs able to re-establish homeostasis in the dopaminergic transmission in Parkinson's disease, the compound N-2,6- dichloro-aralkyl-2-aminoindane 4 was designed through medicinal chemistry strategies that contain pharmacophoric approximations of prodrugs. The pharmacological evaluation of compound 4 in the stereotyped behavior of male Sprague Dawley rats showed agonistic activity through the activation of central dopaminergic mechanisms and a higher selectivity in the responses of stereo- typed behavior characteristic of the basal ganglia over the typical responses from limbic structures.
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Local anesthetic drugs are commonly used to block the conduction function of patient's nerves temporarily for anesthesia during surgery or to provide targeted analgesia after trauma. Compared with general anesthetics, local anesthetics makes less impact on the physiological status and alleviates pain complications in the presence of clear consciousness. However, its clinical application is still limited by its systemic toxicity, as well as toxicity to nerves and muscles, duration of action and lack of penetration. Nanotechnology can help it penetrate the physiological barrier, prolong the time of nerve block, and reduce toxic side effects. In addition, by building a light-responsive release system, local anesthetics can be released on demand, enhancing drug effectiveness and safety. However, in addition to the problems of poor consistency and high production costs, the system of light response release is still limited in application due to the limitation of the depth of penetration of the tissue. According to the current research progress, this paper briefly introduces and analyzes the main dosage forms, hoping to provide new ideas for the responsive release of local anesthetic drugs.
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Since the application of biomedical nanotechnology in the field of drug delivery breathes new life into the research and development of high-end innovative agents, a substantial number of novel nano-drug delivery systems (nano-DDSs) have been successively developed and applied in the clinical practice. Among them, small molecule pure drug and prodrug-based nanoassemblies have grasped great attention, owing to the facile fabrication, ultrahigh drug loading and feasible industrial production. Herein, we provide an overview on the latest updates of small-molecule nanoassemblies. Firstly, the self-assembled prodrug-based nano-DDSs are introduced, including nanoassemblies formed by amphiphilic monomeric prodrugs, hydrophobic monomeric prodrugs and dimer monomeric prodrugs. Then, the recent advances on nanoassemblies of small molecule pure chemical drugs and biological drugs are presented. Furthermore, carrier-free small-molecule hybrid nanoassemblies of pure drugs and/or prodrugs are summarized and analyzed. Finally, the rational design, application prospects and clinical challenges of small-molecule self-assembled nano-DDSs are discussed and highlighted. This review aims to provide scientific reference for constructing the next generation of nanomedicines.
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Metastasis and resistance are main causes to affect the outcome of the current anticancer therapies. Heat shock protein 90 (Hsp90) as an ATP-dependent molecular chaperone takes important role in the tumor metastasis and resistance. Targeting Hsp90 and downregulating its expression show promising in inhibiting tumor metastasis and resistance. In this study, a redox-responsive dual-drug nanocarrier was constructed for the effective delivery of a commonly used chemotherapeutic drug PTX, and a COA-modified 4-arm PEG polymer (4PSC) was synthesized. COA, an active component in oleanolic acid that exerts strong antitumor activity by downregulating Hsp90 expression, was used as a structural and functional element to endow 4PSC with redox responsiveness and Hsp90 inhibitory activity. Our results showed that 4PSC/PTX nanomicelles efficiently delivered PTX and COA to tumor locations without inducing systemic toxicity. By blocking the Hsp90 signaling pathway, 4PSC significantly enhanced the antitumor effect of PTX, inhibiting tumor proliferation and invasiveness as well as chemotherapy-induced resistance in vitro. Remarkable results were further confirmed in vivo with two preclinical tumor models. These findings demonstrate that the COA-modified 4PSC drug delivery nanosystem provides a potential platform for enhancing the efficacy of chemotherapies.
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ProTide technology is a kind of prodrug design strategy invented by the team of Christopher McGuigan. ProTides are aryloxyphosphoramidates (or aryloxyphosphonamidates) which contain a phosphorus atom combined with an amino acid ester and an aryloxy group. These prodrugs can efficiently cross the cell membrane and escape from the first rate-limiting step of phosphorylation, which afford effective solutions to the drawbacks of current nucleoside analogues. At present, ProTide technology has been extensively applied in the field of antiviral research. It has been successful in providing a number of approved drugs and clinical candidates, such as sofosbuvir and so much more, highlighting the promising future in drug discovery. This review summarizes the brief history and characteristics of ProTide technology, as well as its application in the exploration of antiviral drugs.
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Immunotherapy combined with effective therapeutics such as chemotherapy and photodynamic therapy have been shown to be a successful strategy to activate anti-tumor immune responses for improved anticancer treatment. However, developing multifunctional biodegradable, biocompatible, low-toxic but highly efficient, and clinically available transformed nano-immunostimulants remains a challenge and is in great demand. Herein, we report and design of a novel carrier-free photo-chemotherapeutic nano-prodrug COS-BA/Ce6 NPs by combining three multifunctional components-a self-assembled natural small molecule betulinic acid (BA), a water-soluble chitosan oligosaccharide (COS), and a low toxic photosensitizer chlorin e6 (Ce6)-to augment the antitumor efficacy of the immune adjuvant anti-PD-L1-mediated cancer immunotherapy. We show that the designed nanodrugs harbored a smart and distinctive "dormancy" characteristic in chemotherapeutic effect with desired lower cytotoxicity, and multiple favorable therapeutic features including improved 1O2 generation induced by the reduced energy gap of Ce6, pH-responsiveness, good biodegradability, and biocompatibility, ensuring a highly efficient, synergistic photochemotherapy. Moreover, when combined with anti-PD-L1 therapy, both nano-coassembly based chemotherapy and chemotherapy/photodynamic therapy (PDT) could effectively activate antitumor immunity when treating primary or distant tumors, opening up potentially attractive possibilities for clinical immunotherapy.
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The solid-phase microextraction technique quantifies analytes without considerably affecting the sample composition.Herein,a proof-of-concept study was conducted to demonstrate the use of coated probe electrospray ionization(coated-PESI)and coated blade spray(CBS)as ambient mass spectrometry ap-proaches for monitoring drug biotransformation.The ability of these methods was investigated for monitoring the dephosphorylation of a prodrug,combretastatin A4 phosphate(CA4P),into its active form,combretastatin A4(CA4),in a cell culture medium supplemented with fetal bovine serum.The CBS spot analysis was modified to achieve the same extraction efficiency as protein precipitation and ob-tained results in 7 min.Because coated-PESI performs extraction without consuming any samples,it is the preferred technique in the case of a limited sample volume.Although coated-PESI only extracts small quantities of analytes,it uses the desorption solvent volume of 5-10 pL,resulting in high sensitivity,thus allowing the detection of compounds after only 1 min of extraction.The biotransformation of CA4P into CA4 via phosphatases occurs within the simple matrix,and the proposed sample preparation techniques are suitable for monitoring the biotransformation.
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A fast and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of prodrug of paclitaxel (Pro-PTX) and paclitaxel (PTX) in rat plasma was developed. The plasma samples were subjected to protein precipitation with acetonitrile (0.1% formic acid), and then separated by LC with an Ultimate AQ-C18 column (50 mm × 3.0 mm, 3 μm) and acetonitrile-1 mmol·L-1 ammonium formate (containing 0.1% formic acid) as the mobile phase. Multiple reaction monitoring (MRM) scanning mode was used to detect the ion responses m/z 983.4→415.2 (Pro-PTX), m/z 854.4→286.1 (PTX) and m/z 808.3→527.2 (Docetaxel, internal standard) by using a triple quadrupole tandem mass spectrometer with electrospray ionization source and positive ion mode. The method validation results show that the linear ranges of Pro-PTX and PTX in plasma were 2.00-500 ng·mL-1 (r > 0.99) and 4.00-1 000 ng·mL-1 (r > 0.99), the lower limit of quantification was 2.00 ng·mL-1 and 4.00 ng·mL-1, respectively; the quality control samples with low, medium and high concentrations of Pro-PTX and PTX were within the batch, the relative standard deviation (RSD) between batches were all less than 9%; the relative deviation (RE) was within the range of ± 9%; In the stability test, both Pro-PTX and PTX in plasma were stable under various storage conditions. The method was sensitive, specific, and reproducible, and was suitable for the pharmacokinetic study of Pro-PTX in rats. Animal experiments were approved by the Ethics Committee of Laboratory Animal Management and Animal Welfare, Institute of Materia Medica, Chinese Academy of Medical Sciences (No.: 00003552).
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Aberrant activation of oncogenic signaling pathways in tumors can promote resistance to the antitumor immune response. However, single blockade of these pathways is usually ineffective because of the complex crosstalk and feedback among oncogenic signaling pathways. The enhanced toxicity of free small molecule inhibitor combinations is considered an insurmountable barrier to their clinical applications. To circumvent this issue, we rationally designed an effective tumor microenvironment-activatable prodrug nanomicelle (PNM) for cancer therapy. PNM was engineered by integrating the PI3K/mTOR inhibitor PF-04691502 (PF) and the broad spectrum CDK inhibitor flavopiridol (Flav) into a single nanoplatform, which showed tumor-specific accumulation, activation and deep penetration in response to the high glutathione (GSH) tumoral microenvironment. The codelivery of PF and Flav could trigger gasdermin E (GSDME)-based immunogenic pyroptosis of tumor cells to elicit a robust antitumor immune response. Furthermore, the combination of PNM-induced immunogenic pyroptosis with anti-programmed cell death-1 (αPD-1) immunotherapy further boosted the antitumor effect and prolonged the survival time of mice. Collectively, these results indicated that the pyroptosis-induced nanoplatform codelivery of PI3K/mTOR and CDK inhibitors can reprogram the immunosuppressive tumor microenvironment and efficiently improve checkpoint blockade cancer immunotherapy.
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PD-1 and PD-L1 antibodies have brought about extraordinary clinical benefits for cancer patients, and their indications are expanding incessantly. Currently, most PD-1/PD-L1 agents are administered intravenously, which may be uncomfortable for some cancer patients. Herein, we develop a novel oral-delivered small molecular, YPD-29B, which specifically targets human PD-L1. Our data suggested that YPD-29B could potently and selectively block the interaction between PD-L1 and PD-1, but did not inhibit any other immune checkpoints. Mechanistically, YPD-29B induced human PD-L1 dimerization and internalization, which subsequently activated T lymphocytes and therefore overcomes immunity tolerance in vitro. YDP-29B was modified as the YPD-30 prodrug to improve druggability. Using humanized mice with human PD-1 xenografts of human PD-L1 knock-in mouse MC38 cancer cells, we demonstrated that YPD-30 exhibited significant antitumor activity and was well tolerated in vivo. Taken together, our results indicate that YPD-30 serves as a promising therapeutic candidate for anti-human PD-L1 cancer immunotherapy.
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Cancer immunotherapy is impaired by the intrinsic and adaptive immune resistance. Herein, a bispecific prodrug nanoparticle was engineered for circumventing immune evasion of the tumor cells by targeting multiple immune resistance mechanisms. A disulfide bond-linked bispecific prodrug of NLG919 and JQ1 (namely NJ) was synthesized and self-assembled into a prodrug nanoparticle, which was subsequently coated with a photosensitizer-modified and tumor acidity-activatable diblock copolymer PHP for tumor-specific delivery of NJ. Upon tumor accumulation via passive tumor targeting, the polymeric shell was detached for facilitating intracellular uptake of the bispecific prodrug. NJ was then activated inside the tumor cells for releasing JQ1 and NLG919 via glutathione-mediated cleavage of the disulfide bond. JQ1 is a bromodomain-containing protein 4 inhibitor for abolishing interferon gamma-triggered expression of programmed death ligand 1. In contrast, NLG919 suppresses indoleamine-2,3-dioxygenase 1-mediated tryptophan consumption in the tumor microenvironment, which thus restores robust antitumor immune responses. Photodynamic therapy (PDT) was performed to elicit antitumor immunogenicity by triggering immunogenic cell death of the tumor cells. The combination of PDT and the bispecific prodrug nanoparticle might represent a novel strategy for blockading multiple immune evasion pathways and improving cancer immunotherapy.
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@#A novel allicin pro-drug tablet containing antacid pellets was developed to realize pH-regulated allicin release and to guarantee allicin yield in stomach environment.Firstly, allicin precursor pellets containing antacid pellet were prepared and artificial gastric juice was used as the medium to determine the yield of the allicin.Then, the total lipid cholesterol (TC), triglyceride cholesterol (TG), high density lipoprotein (HDL-C) and low-density lipoprotein (LDL-C) were used as indicators to study the hypolipidemic effect of allicin precursor pellets in rats.The dissolution test showed that in artificial gastric juice, the yield of allicin-containing antacid pellets exceeded 90%.In pharmacodynamic studies, it was found that antacid pellets showed the expected hypolipidemic effect on hyperlipidemia rats compared without antacid pellets.There was a very significant difference in blood lipid levels between the two test groups (P < 0.05).The allicin pro-drug tablets containing antacid pellets can effectively lower blood lipids.
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Precisely delivering combinational therapeutic agents has become a crucial challenge for anti-tumor treatment. In this study, a novel redox-responsive polymeric prodrug (molecular weight, MW: 93.5 kDa) was produced by reversible addition-fragmentation chain transfer (RAFT) polymerization. The amphiphilic block polymer-doxorubicin (DOX) prodrug was employed to deliver a hydrophobic photosensitizer (PS), chlorin e6 (Ce6), and the as-prepared nanoscale system [NPs(Ce6)] was investigated as a chemo-photodynamic anti-cancer agent. The glutathione (GSH)-cleavable disulfide bond was inserted into the backbone of the polymer for biodegradation inside tumor cells, and DOX conjugated onto the polymer with a disulfide bond was successfully released intracellularly. NPs(Ce6) released DOX and Ce6 with their original molecular structures and degraded into segments with low MWs of 41.2 kDa in the presence of GSH. NPs(Ce6) showed a chemo-photodynamic therapeutic effect to kill 4T1 murine breast cancer cells, which was confirmed from a collapsed cell morphology, a lifted level in the intracellular reactive oxygen species, a reduced viability and induced apoptosis. Moreover, ex vivo fluorescence images indicated that NPs(Ce6) retained in the tumor, and exhibited a remarkable in vivo anticancer efficacy. The combinational therapy showed a significantly increased tumor growth inhibition (TGI, 58.53%). Therefore, the redox-responsive, amphiphilic block polymeric prodrug could have a great potential as a chemo-photodynamic anti-cancer agent.
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HIV/AIDS, tuberculose, malária e as doenças tropicais negligenciadas representam uma grande preocupação em Saúde em muitas regiões do mundo. Os fármacos disponíveis para o tratamento apresentam diversos problemas, tais como toxicidade e resistência ao parasita. Mesmo com esse triste panorama, o investimento em pesquisa nessa área é, ainda, pouco significativo. Assim, dentre os métodos de modificação molecular para melhorar propriedades farmacêuticas, farmacocinéticas e/ou farmacodinâmica de compostos bioativos destaca-se a latenciação. Já os dendrímeros vêm despertando interesse em aplicações biológicas, principalmente como transportadores de fármacos, além de atuarem como transportadores de genes, imagem em diagnóstico e compostos com ação per se. Face ao exposto e tendo em vista o caráter promissor dos dendrímeros como sistemas de drug delivery, o objetivo deste trabalho foi a síntese de pró-fármacos dendriméricos potencialmente ativos em malária e tuberculose. Os dendrímeros de Bis-MPA (gerações 0, 1 e 2) foram sintetizados pelo grupo do Professor Scott Grayson, da Tulane University (EUA). No Brasil, foram feitas as funcionalizações destes compostos, através do acoplamento do ácido succínico (que funciona como espaçante) e as moléculas ativas. Selecionaram-se as seguintes substâncias: (1) primaquina, com ação antimalárica e (2) isoniazida, de ação nos primeiros estágios da tuberculose. Foram sintetizados os pró-fármacos dendriméricos de isoniazida nas gerações 0 e 1 (G0-Iso e G1-Iso), e primaquina nas gerações 0, 1 e 2 (G0-Pq, G1-Pq e G2Pq). Importante mencionar que os resultados de Ressonância Magnética e Nuclear de 1H e de 13C demostraram as obtenções dos respectivos produtos, porém contendo impurezas. Já a análise do resultado proveniente da espectrometria de massas do composto G0-Iso revelou a presença de um subproduto ciclizado da isonizaida succinoilada (CIso-Suc), o qual pode ser um potencial pró-fármaco ou apresentar atividade per se. Como não se conhece este composto, o laboratório coordenado pela Profas Elizabeth Igne Ferreira e Jeanine Giarolla manifestou interesse em pesquisa-lo, principalmente quanto suas propriedades físico- químicas, bem como quanto à atividade biológica. Assim, utilizando metodologia analítica previamente estabelecida para o G0-Iso, os estudos de estabilidade química da CIso-Suc, em diferentes valores de pH, demonstraram a capacidade da forma ciclizada em se converter no protótipo Iso-Suc, majoritariamente em pH 7,4 e 8,5. Como perspectivas, destaca-se a avaliação da estabilidade enzimática deste potencial derivado. Ressalta-se, ainda, a a avaliação da respectiva atividade antimicobacteriana. Em relação aos pró-fármacos, as necessidades de aprimoramentos das sínteses são, também, evidenciadas. Uma vez sintetizados e caracterizados, estes últimos derivados serão avaliados quanto à atividade biológica. Ademais, estudos computacionais, sobretudo simulações de docking molecular, foram desenvolvidos com intuito de se entender o modo de interação de alguns compostos com alvos biológicos pré-determinados
HIV/AIDS, tuberculosis, malaria and neglected diseases are a major health concern in many regions of the world. The drugs available present various problems, such as toxicity and parasite resistance. Even with this sad outlook, research investment in this area is still insignificant. Among the molecular modification methods to improve the pharmaceutical, pharmacokinetic and/or pharmacodynamic properties we stands out prodrug design. On the other hand, dendrimers are arousing interest in biological applications, mainly as drug carriers, besides gene delivery, diagnostic imaging, as well as acting as compounds with activity per se. Considering that, added to the promising dendrimer drug delivery features, the aim of this study was to synthesize potentially active dendrimer prodrugs in malaria and tuberculosis. Bis-MPA dendrimers (generations 0, 1 and 2) were synthesized by the group of Professor Scott Grayson of Tulane University (USA). Herein in Brazil, the compounds were functionalized by coupling succinic acid (spacer group), as well as the active molecules. We selected the following substances: (1) primaquine, with antimalarial action and (2) isoniazid, acting in the early stages of tuberculosis. Isoniazid dendrimer prodrugs were synthesized generations 0 and 1 (G0-Iso and G1-Iso), and primaquine in generations 0, 1 and 2 (G0-Pq, G1-Pq and G2-Pq). It is important to mention that the results related to Nuclear and Magnetic Resonance 113C showed chemical structures features, however with impurities. Analysis of the mass spectrometry regarding G0-Iso has revealed the presence of a cyclized by-product of succinylated isonized (CIso-Suc), which may be a potential prodrug or may presentactivity itself. Using the analytical methodology performed for G0-Iso, ICso-Suc demonstrated its ability to convert the Iso-Suc prototype at different pH values, especially at pH 7.4 and 8.5. As perspectives, we highlight the determinations of the chemical stability of ICsoSuc at pH 1.5 and 6.0, as well as the evaluation of the enzymatic stability. We will also investigate the respective antimicobacterial activities. Regarding prodrugs, the needs for synthesis enhancements are also necessary. Once synthesized and characterized, these latter derivatives will be evaluated for biological activity. Moreover, computational studies, especially molecular docking simulations, were developed in order to understand the mode of interaction of some compounds with predetermined biological targets
Subject(s)
Tuberculosis/pathology , Prodrugs/analysis , Dendrimers/adverse effects , Malaria/pathology , Mass Spectrometry/methods , Training Support/classification , Pharmaceutical Preparations/analysis , Magnetic Resonance Spectroscopy/methods , HIV/pathogenicity , Pharmacologic Actions , Neglected Diseases/complications , Antimalarials/analysisABSTRACT
A commercial albumin-bound paclitaxel nano-formulation has been considered a gold standard against breast cancer. However, its application still restricted unfavorable pharmacokinetics and the immunogenicity of exogenous albumin carrier. Herein, we report an albumin-bound tumor redox-responsive paclitaxel prodrugs nano-delivery strategy. Using diverse linkages (thioether bond and disulfide bond), paclitaxel (PTX) was conjugated with an albumin-binding maleimide (MAL) functional group. These pure PTX prodrugs could self-assemble to form uniform and spherical nanoparticles (NPs) in aqueous solution without any excipients. By immediately binding to blood circulating albumin after intravenous administration, NPs are rapidly disintegrated into small prodrug/albumin nanoaggregates
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Nature has endowed gaseous molecules such as O
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For local treatment of ulcerative colitis, a new azoreductase driven prodrug CDDO-AZO from bardoxolone methyl (CDDO-Me) and 5-aminosalicylate (5-ASA) was designed, synthesized and biologically evaluated. It is proposed that orally administrated CDDO-AZO is stable before reaching the colon, while it can also be triggered by the presence of azoreductase in the colon to fragment into CDDO-Me and 5-ASA, generating potent anti-colitis effects. Superior to olsalazine (OLS, a clinically used drug for ulcerative colitis) and CDDO-Me plus 5-ASA, CDDO-AZO significantly attenuated inflammatory colitis symptoms in DSS-induced chronic colitis mice, which suggested that CDDO-AZO may be a promising anti-ulcerative colitis agent.
Subject(s)
Animals , Mice , Colitis/drug therapy , Mesalamine/pharmacology , Nitroreductases , Oleanolic Acid/pharmacology , ProdrugsABSTRACT
OBJECTIVE：To prepare supersaturated system of lip ophilic aci clovir（ACV）prodrug，and to increase the cutaneous bioavailability of ACV. METHODS ：Three prodrugs of ACV were synthesized by anhydride acylation ，i.e. aciclovir acetate （ACV-Ace），butyrate（ACV-But）and hexanoate （ACV-Hex）. The structures of ACV and three ACV prodrugs were confirmed by 1H-NMR and HRESI-MS ；the concentrations of ACV and three ACV prodrugs were determined by UPLC-triple quadrupole tandem mass spectrometry ，and saturated solubility of them in different volume fractions of propylene glycol-water solution was calculated. The compound with the greatest potential of form supersaturated system was screened out. The supersaturated system of that compound was prepared by co-solvent method. The effect of hydroxypropyl methylcellulose E 3 （HPMC E 3） on its physical stability was observed by light microscope. Vertical Franz diffusion cells were used to study the effects of degree of supersaturation （DS）and HPMC E 3 on the deposited amount of drug in the excised porcine skin after using the supersaturated system for 1 h. The distribution of ACV in the excised porcine skin was determined by frozen slicing stratified quantitative method after using the supersaturated system and marketed aciclovir cream for 1 h. RESULTS ：Three ACV prodrugs were successfully synthesized. The established quantification methods met the requirements of biological sample analysis. Among all of the three ACV prodrugs ， ACV-Hex showed the lowest saturated solubility in water [ （0.5±0.0）mmol/L] a nd the highest saturated solubility in propylene glycol [（53.4 ± 14.2）mmol/L]，which made it potentially feasible to form supersaturated system with high DS. In 10％propylene glycol-water system ，the addition of HPMC E 3 163.com enabled ACV-Hex supersaturated systems ，with DS no morethan 4，to maintain physical stability within 1 h. The total deposited amount （ACV + ACV-Hex ） in skin after the application of ACV-Hex supersaturated system with DS of 4 for 1 h was higher than that after the application of ACV-Hex supersaturated system with DS less than 4 or without HPMC E 3. In addition ，the concentration of ACV in the basal epidermis （skin thickness was 100-160 mm）by supersaturated system was significantly higher than that of the marketed aciclovir cream （P＜0.05）. CONCLUSIONS：ACV-Hex，the lipophilic prodrug of ACV ，can form stable supersaturated system with DS of 4 in 10％ propylene glycol-water system in the presence of HPMC E 3. High concentration of ACV could be accumulated in the basal epidermis after the skin was exposed to supersaturated system for 1 h，which may be valuable for local treatment skin infection of herpes simplex virus .
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Compared with normal tissues and cells, the tumor microenvironment has significant differences. For example, glutathione-related metabolic enzymes and reactive oxygen species are highly expressed in different subcellular structures, resulting in an unbalanced redox state. Aiming at the specific redox state in tumor tissues and cells, a series of small molecule prodrug self-assembled nanoparticles can be designed and connected by intelligent response linkers including disulfide bonds, sulfide bonds, and selenium bonds, thioketal bonds, etc. The in vitro and in vivo efficiency and metabolic mode of these nanoparticles are related to the type of linker. This review will summarize the tumor redox microenvironment, the design of intelligent responsive small molecule prodrug nanoparticles, and the metabolic pathways of small molecule prodrug nanoparticles with different connecting linkers and their relationship with drug efficacy.
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Metal-based carbon monoxide (CO)-releasing molecules have been shown to exert anti-inflammatory and anti-oxidative properties maintaining gastric mucosal integrity. We are interested in further development of metal-free CO-based therapeutics for oral administration. Thus, we examine the protective effect of representative CO prodrug, BW-CO-111, in rat models of gastric damage induced by necrotic ethanol or aspirin, a representative non-steroidal anti-inflammatory drug. Treatment effectiveness was assessed by measuring the microscopic/macroscopic gastric damage area and gastric blood flow by laser flowmetry. Gastric mucosal mRNA and/or protein expressions of HMOX1, HMOX2, nuclear factor erythroid 2-related factor 2, COX1, COX2,