Oral antivirals for COVID-19 among patients with cancer.

PURPOSE: Immunocompromised individuals, such as those diagnosed with cancer, are at a significantly higher risk for severe illness and mortality when infected with SARS-CoV-2 (COVID-19) than the general population. Two oral antiviral treatments are approved for COVID-19: Paxlovid® (nirmatrelvir/ritonavir) and Lagevrio® (molnupiravir). There is a paucity of data regarding the benefit from these antivirals among immunocompromised patients with cancer, and recent studies have questioned their efficacy among vaccinated patients, even those with risk factors for severe COVID-19. METHODS: We evaluated the efficacy and safety of nirmatrelvir/ritonavir and molnupiravir in preventing severe illness and death using our database of 457 patients with cancer and COVID-19 from Brown University-affiliated hospitals. RESULTS: Sixty-seven patients received nirmatrelvir/ritonavir or molnupiravir and were compared to 45 concurrent controls who received no antiviral treatment despite being eligible to receive it. Administration of nirmatrelvir/ritonavir or molnupiravir was associated with improved survival and lower 90-day all-cause and COVID-19-attributed mortality (p < 0.05) and with lower peak O2 requirements (ordinal odds ratio [OR] 1.52, 95% confidence interval [CI] 0.92-2.56). CONCLUSION: Acknowledging the small size of our sample as a limitation, we concluded that early antiviral treatment might be beneficial to immunocompromised individuals, particularly those with cancer, when infected with SARS-CoV-2. Larger-scale, well-stratified studies are needed in this patient population.

Molnupiravir increases SARS-CoV-2 genome diversity and complexity: A case-control cohort study.

Molnupiravir, an oral direct-acting antiviral effective in vitro against SARS-CoV-2, has been largely employed during the COVID-19 pandemic, since December 2021. After marketing and widespread usage, a progressive increase in SARS-CoV-2 lineages characterized by a higher transition/transversion ratio, a characteristic signature of molnupiravir action, appeared in the Global Initiative on Sharing All Influenza Data (GISAID) and International Nucleotide Sequence Database Collaboration (INSDC) databases. Here, we assessed the drug effects by SARS-CoV-2 whole-genome sequencing on 38 molnupiravir-treated persistently positive COVID-19 outpatients tested before and after treatment. Seventeen tixagevimab/cilgavimab-treated outpatients served as controls. Mutational analyses confirmed that SARS-CoV-2 exhibits an increased transition/transversion ratio seven days after initiation of molnupiravir. Moreover we observed an increased G->A ratio compared to controls, which was not related to apolipoprotein B mRNAediting enzyme, catalytic polypeptide-like (APOBEC) activity. In addition, we demonstrated for the first time an increased diversity and complexity of the viral quasispecies.

Safety of RNA-Dependent RNA Polymerase Inhibitors, Molnupiravir and VV116, for Oral Treatment of COVID-19: A Meta-Analysis.

Background: The RNA-dependent RNA polymerase (RdRp) inhibitors, molnupiravir and VV116, have the potential to maximize clinical benefits in the oral treatment of COVID-19. Subjects who consume these drugs may experience an increased incidence of adverse events. This study aimed to evaluate the safety profile of molnupiravir and VV116. Methods: A comprehensive search of scientific and medical databases, such as PubMed Central/Medline, Embase, Web of Science, and Cochrane Library, was conducted to find relevant articles in English from January 2020 to June 2023. Any kind of adverse events reported in the study were pooled and analyzed in the drug group versus the control group. Estimates of risk effects were summarized through the random effects model using Review Manager version 5.2, and sensitivity analysis was performed by Stata 17.0 software. Results: Fifteen studies involving 32,796 subjects were included. Eleven studies were placebo-controlled, and four were Paxlovid-controlled. Twelve studies reported adverse events for molnupiravir, and three studies described adverse events for VV116. The total odds ratio (OR) for adverse events in the RdRp inhibitor versus the placebo-controlled group was 1.01 (95% CI=0.84-1.22; I2=26%), P=0.88. The total OR for adverse events in the RdRp inhibitor versus the Paxlovid-controlled group was 0.32 (95% CI=0.16-0.65; I2=87%), P=0.002. Individual drug subgroup analysis in the placebo-controlled study showed that compared with the placebo group, a total OR for adverse events was 0.97 (95% CI, 0.85-1.10; I2=0%) in the molnupiravir group and 3.77 (95% CI=0.08-175.77; I2=85%) in the VV116 group. Conclusion: The RdRp inhibitors molnupiravir and VV116 are safe for oral treatment of COVID-19. Further evidence is necessary that RdRp inhibitors have a higher safety profile than Paxlovid.

Impact of histone deacetylase inhibition and arimoclomol on heat shock protein expression and disease biomarkers in primary culture models of familial ALS.

Protein misfolding and mislocalization are common themes in neurodegenerative disorders, including motor neuron disease, and amyotrophic lateral sclerosis (ALS). Maintaining proteostasis is a crosscutting therapeutic target, including the upregulation of heat shock proteins (HSP) to increase chaperoning capacity. Motor neurons have a high threshold for upregulating stress-inducible HSPA1A, but constitutively express high levels of HSPA8. This study compared the expression of these HSPs in cultured motor neurons expressing three variants linked to familial ALS: TAR DNA binding protein 43 kDa (TDP-43)G348C, fused in sarcoma (FUS)R521G, or superoxide dismutase I (SOD1)G93A. All variants were poor inducers of Hspa1a, and reduced levels of Hspa8 mRNA and protein, indicating multiple compromises in chaperoning capacity. To promote HSP expression, cultures were treated with the putative HSP coinducer, arimoclomol, and class I histone deacetylase inhibitors, to promote active chromatin for transcription, and with the combination. Treatments had variable, often different effects on the expression of Hspa1a and Hspa8, depending on the ALS variant expressed, mRNA distribution (somata and dendrites), and biomarker of toxicity measured (histone acetylation, maintaining nuclear TDP-43 and the neuronal Brm/Brg-associated factor chromatin remodeling complex component Brg1, mitochondrial transport, FUS aggregation). Overall, histone deacetylase inhibition alone was effective on more measures than arimoclomol. As in the FUS model, arimoclomol failed to induce HSPA1A or preserve Hspa8 mRNA in the TDP-43 model, despite preserving nuclear TDP-43 and Brg1, indicating neuroprotective properties other than HSP induction. The data speak to the complexity of drug mechanisms against multiple biomarkers of ALS pathogenesis, as well as to the importance of HSPA8 for neuronal proteostasis in both somata and dendrites.

Inhibition of kynurenine production by N,O-substituted hydroxylamine derivatives.

The inhibition of kynurenine production is considered a promising target for cancer immunotherapy. In this study, an amino acid derivative, compound 1 was discovered using a cell-based assay with our screening library. Compound 1 suppressed kynurenine production without inhibiting indoleamine 2,3-dioxygenase 1 (IDO1) activity. The activity of 1 was derived from the inhibition of IDO1 by a metabolite of 1, O-benzylhydroxylamine (OBHA, 2a). A series of N-substituted 2a derivatives that exhibit potent activity in cell-based assays may represent effective prodrugs. Therefore, we synthesized and evaluated novel N,O-substituted hydroxylamine derivatives. The structure-activity relationships revealed that N,O-substituted hydroxylamine 2c inhibits kynurenine production in a cell-based assay. We conducted an in vivo experiment with 2c, although the effectiveness of O-substituted hydroxylamine derivatives in vivo has not been previously reported. The results indicate that N,O-substituted hydroxylamine derivatives are promising IDO1 inhibitors.

Peptide-Directed Attachment of Hydroxylamines to Specific Lysines of IgG Antibodies for Bioconjugations with Acylboronates.

The role of monoclonal antibodies as vehicles to deliver payloads has evolved as a powerful tool in cancer therapy in recent years. The clinical development of therapeutic antibody conjugates with precise payloads holds great promise for targeted therapeutic interventions. The use of affinity-peptide mediated functionalization of native off-the-shelf antibodies offers an effective approach to selectively modify IgG antibodies with a drug-antibody ratio (DAR) of 2. Here, we report the traceless, peptide-directed attachment of two hydroxylamines to native IgGs followed by chemoselective potassium acyltrifluoroborate (KAT) ligation with quinolinium acyltrifluoroborates (QATs), which provide enhanced ligation rates with hydroxylamines under physiological conditions. By applying KAT ligation to the modified antibodies, conjugation of small molecules, proteins, and oligonucleotides to off-the-shelf IgGs proceeds efficiently, in good yields, and with simultaneous cleavage of the affinity peptide-directing moiety.

Novel Epigenetic Modifiers of Histones Presenting Potent Inhibitory Effects on Adenoid Cystic Carcinoma Stemness and Invasive Properties.

Adenoid cystic carcinoma (ACC) is a rare neoplasm known for its indolent clinical course, risk of perineural invasion, and late onset of distant metastasis. Due to the scarcity of samples and the tumor's rarity, progress in developing effective treatments has been historically limited. To tackle this issue, a high-throughput screening of epigenetic drugs was conducted to identify compounds capable of disrupting the invasive properties of the tumor and its cancer stem cells (CSCs). ACC cells were screened for changes in tumor viability, chromatin decondensation, Snail inhibition along tumor migration, and disruption of cancer stem cells. Seven compounds showed potential clinical interest, and further validation showed that Scriptaid emerged as a promising candidate for treating ACC invasion. Scriptaid demonstrated a favorable cellular toxicity index, effectively inhibited Snail expression, induced hyperacetylation of histone, reduced cell migration, and effectively disrupted tumorspheres. Additionally, LMK235 displayed encouraging results in four out of five validation assays, further highlighting its potential in combating tumor invasion in ACC. By targeting the invasive properties of the tumor and CSCs, Scriptaid and LMK235 hold promise as potential treatments for ACC, with the potential to improve patient outcomes and pave the way for further research in this critical area.

SARS-CoV-2 Antiviral Prescribing Gaps Among Nonhospitalized High-Risk Adults.

Within a multistate clinical cohort, SARS-CoV-2 antiviral prescribing patterns were evaluated from April 2022-June 2023 among nonhospitalized patients with SARS-CoV-2 with risk factors for severe COVID-19. Among 3247 adults, only 31.9% were prescribed an antiviral agent (87.6% nirmatrelvir/ritonavir, 11.9% molnupiravir, 0.5% remdesivir), highlighting the need to identify and address treatment barriers.

Amino acid and protein specificity of protein fatty acylation in C. elegans.

Protein lipidation plays critical roles in regulating protein function and localization. However, the chemical diversity and specificity of fatty acyl group utilization have not been investigated using untargeted approaches, and it is unclear to what extent structures and biosynthetic origins of S-acyl moieties differ from N- and O-fatty acylation. Here, we show that fatty acylation patterns in Caenorhabditis elegans differ markedly between different amino acid residues. Hydroxylamine capture revealed predominant cysteine S-acylation with 15-methylhexadecanoic acid (isoC17:0), a monomethyl branched-chain fatty acid (mmBCFA) derived from endogenous leucine catabolism. In contrast, enzymatic protein hydrolysis showed that N-terminal glycine was acylated almost exclusively with straight-chain myristic acid, whereas lysine was acylated preferentially with two different mmBCFAs and serine was acylated promiscuously with a broad range of fatty acids, including eicosapentaenoic acid. Global profiling of fatty acylated proteins using a set of click chemistry-capable alkyne probes for branched- and straight-chain fatty acids uncovered 1,013 S-acylated proteins and 510 hydroxylamine-resistant N- or O-acylated proteins. Subsets of S-acylated proteins were labeled almost exclusively by either a branched-chain or a straight-chain probe, demonstrating acylation specificity at the protein level. Acylation specificity was confirmed for selected examples, including the S-acyltransferase DHHC-10. Last, homology searches for the identified acylated proteins revealed a high degree of conservation of acylation site patterns across metazoa. Our results show that protein fatty acylation patterns integrate distinct branches of lipid metabolism in a residue- and protein-specific manner, providing a basis for mechanistic studies at both the amino acid and protein levels.

Characteristics and Outcomes of US Veterans With Immunocompromised Conditions at High Risk of SARS-CoV-2 Infection With or Without Receipt of Oral Antiviral Agents.

OBJECTIVES: Molnupiravir and nirmatrelvir-ritonavir were the first oral antiviral agents to demonstrate reduced hospitalization or death in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but patients with immunocompromised conditions were not well-represented. The objective of this study was to characterize and compare the clinical outcomes of US veterans with immunocompromised conditions prescribed oral antivirals with those who did not receive oral antivirals for mild-to-moderate SARS-CoV-2 active infection. METHODS: This was a retrospective, observational, nationwide propensity-matched analysis of US veterans with immunocompromised conditions who developed documented SARS-CoV-2 infection. The primary outcome was the composite of any hospitalization or death within 30 days of diagnosis. Secondary outcomes included 30-day comparative rates of (1) any hospitalization, (2) death, (3) intensive care requirement, and (4) subset analyses of outcomes by oral antiviral used and vaccination status. RESULTS: The composite primary outcome was significantly lower in patients receiving oral antiviral therapy compared with those who did not (23/390 [5.9%] vs 57/390 [14.6%]; odds ratio, 0.37; 95% confidence interval, .22-.61). This difference was driven largely by fewer deaths in the oral antiviral group (1/390 [0.3%] vs 19/390 [4.9%]; odds ratio, 0.05; 95% confidence interval, .007-.38). There was no significant difference in rate of intensive care requirement. The composite outcome was improved in vaccinated patients (completing the first series or first booster dose) who received oral antiviral agents compared with those who did not receive oral antiviral agents. Compared with those prescribed nirmatrelvir-ritonavir, patients given molnupiravir were older, had a higher incidence of cautions/contraindications, greater prevalence of tobacco use, and more cardiovascular complications. CONCLUSIONS: Use of molnupiravir or nirmatrelvir-ritonavir was associated with lower incidences of hospitalization or death within 30 days of diagnosis in US veterans with immunocompromised conditions, regardless of vaccination status. These findings support the use of either oral antiviral in this patient population.

Discovery of a Hydroxylamine-Based Brain-Penetrant EGFR Inhibitor for Metastatic Non-Small-Cell Lung Cancer.

Metastases to the brain remain a significant problem in lung cancer, as treatment by most small-molecule targeted therapies is severely limited by efflux transporters at the blood-brain barrier (BBB). Here, we report the discovery of a selective, orally bioavailable, epidermal growth factor receptor (EGFR) inhibitor, 9, that exhibits high brain penetration and potent activity in osimertinib-resistant cell lines bearing L858R/C797S and exon19del/C797S EGFR resistance mutations. In vivo, 9 induced tumor regression in an intracranial patient-derived xenograft (PDX) murine model suggesting it as a potential lead for the treatment of localized and metastatic non-small-cell lung cancer (NSCLC) driven by activating mutant bearing EGFR. Overall, we demonstrate that an underrepresented functional group in medicinal chemistry, the trisubstituted hydroxylamine moiety, can be incorporated into a drug scaffold without the toxicity commonly surmised to accompany these units, all while maintaining potent biological activity and without the molecular weight creep common to drug optimization campaigns.

Electroanalytical overview: the sensing of hydroxylamine.

One of the principal raw ingredients used in the manufacturing of pharmaceuticals, nuclear fuel, and semiconductors is hydroxylamine, a mutagenic and carcinogenic substance, ranking high on the list of environmental contaminants. Electrochemical methods for monitoring hydroxylamine have the advantage of being portable, quick, affordable, simple, sensitive, and selective enough to maintain adequate constraints in contrast with conventional yet laboratory based quantification methods. This review outlines the most recent advancements in electroanalysis directed toward the sensing of hydroxylamine. Potential future advancements in this field are also offered, along with a discussion of method validation and the use of such devices in real samples for the determination of hydroxylamine.

Factors Influencing COVID-19 Risk: Insights From Molnupiravir Exposure-Response Modeling of Clinical Outcomes.

Molnupiravir (MOV) is an oral antiviral for the treatment of coronavirus disease 2019 (COVID-19) in outpatient settings. This analysis investigated the relationship between ß-D-N4-hydroxycytidine (NHC) pharmacokinetics and clinical outcomes in patients with mild to moderate COVID-19 in the phase III part of the randomized, double-blind, placebo-controlled MOVe-OUT trial. Logistic regression models of the dependency of outcomes on exposures and covariates were constructed using a multistep process. Influential covariates were identified first using placebo arm data, followed by assessment of exposure-dependency in drug effect using data from both the placebo and MOV arms. The exposure-response (E-R) analysis included 1,313 participants; 630 received MOV and 683 received placebo. Baseline viral load, baseline disease severity, age, weight, viral clade, active cancer, and diabetes were identified as significant determinants of response using placebo data. Absolute measures of viral load on days 5 and 10 were strong on-treatment predictors of hospitalization. An additive area under the curve (AUC)-based maximum effect (Emax ) model with a fixed Hill coefficient of 1 best represented the exposure-dependency in drug effect and the AUC50 was estimated to be 19,900 nM hour. Patients at 800 mg achieved near maximal response, which was larger than for 200 or 400 mg. The final E-R model was externally validated and predicted that the relative reduction in hospitalization with MOV treatment would vary with patient characteristics and factors in the population. In conclusion, the E-R results support the MOV dose of 800 mg twice daily to treat COVID-19. Many patient characteristics and factors impacted outcomes beyond drug exposures.

Chemical Cyclic Amplification: Hydroxylamine Boosts the Fenton Reaction for Versatile and Scalable Biosensing.

Nucleic acid detection is undoubtedly one of the most important research fields to meet the medical needs of genetic disease diagnosis, cancer treatment, and infectious disease prevention. However, the practical detection methods based on biological amplification are complex and time-consuming and require highly trained operators. Herein, we report a simple, rapid, and sensitive method for the nucleic acid assay by fluorescence or naked eye using chemical cyclic amplification. The addition of hydroxylamine (HA) during the Fenton reaction can continuously generate hydroxyl radicals (•OH) via Fe3+/Fe2+ cycle, termed as "hydroxylamine boosts the Fenton reaction (Fenton-HA system)". Meanwhile, the reducing substances, such as terephthalic acid or o-phenylenediamine, react with •OH to generate oxidized substances that can be recognized by the naked eye or detected by fluorescence so as to realize the detection of Fe3+. The concentration of Fe3+ has a good linear relationship with fluorescence intensity in the range of 0.1 to 100 nM, and the limit of detection is calculated to be 0.03 nM (S/N = 3). Subsequently, Fe was introduced into the nucleic acid hybridization system after the Fe source was transformed into Fe3+, and the nucleic acids were indirectly determined by this method. This Fenton-HA system was used for sensing HIV-DNA and miRNA-21 to verify the validity of this method in nucleic acid detection. The detection limits were as low as 2.5 pM for HIV-DNA and 3 pM for miRNA-21. We believe that our work has unlocked an efficient signal amplification strategy, which is expected to develop a new generation of highly sensitive chemical biosensors.

Iron-catalyzed regioselective synthesis of (E)-vinyl sulfones mediated by unprotected hydroxylamines.

An Fe-catalyzed unprotected hydroxylamine mediated Heck-type coupling between sulfinic acids and alkenes for the regioselective synthesis of (E)-vinyl sulfones has been developed. Mechanism studies indicated for the first time that a radical process may be involved and that hydroxylamines play multiple roles, including those of a mild oxidant and an in situ base. It was found for the first time that this transformation not only realizes C-S bond construction promoted by unprotected hydroxylamines, but also provides a practical and complementary method for the preparation of structurally important (E)-vinyl sulfones.

Effects of hydroxylamine on treatment of anaerobic digestate of pig manure in partial nitrification-anaerobic ammonium oxidation.

Partial nitrification-anaerobic ammonium oxidation (PN-anammox) was started up within 40 days by bioaugmentation and aeration control, and its performance in the treatment of anaerobic digestate of pig manure (ADPM) was evaluated. Inhibitors in ADPM decreased the nitrogen removal rate (NRR) by 0.24 g N/L/d. The effect and mechanism of hydroxylamine (NH2OH) alleviation of PN-anammox inhibition during ADPM treatment were investigated. As an intermediate product of anammox and ammonia-oxidizing bacteria, NH2OH strengthened energy metabolism, improved the activity and abundance of functional bacteria, and eliminated miscellaneous bacteria, increasing the average NRR by 31%. However, the average nitrous oxide emission was increased by 10.1% via hydroxylamine oxidation. The results showed that synergy and competition among nitrogen-transforming microorganisms were crucial for NRR and that NH2OH played an essential role in maintaining efficient operation. This study lays a foundation for restoring PN-anammox for treating livestock wastewater.

Multi-DNA Adduct and Abasic Site Quantitation In Vivo by Nano-Liquid Chromatography/High-Resolution Orbitrap Tandem Mass Spectrometry: Methodology for Biomonitoring Colorectal DNA Damage.

Epidemiological and mechanistic studies suggest that processed and red meat consumption and tobacco smoking are associated with colorectal cancer (CRC) risk. Several classes of carcinogens, including N-nitroso compounds (NOCs) in processed meats and heterocyclic aromatic amines (HAAs) and polycyclic aromatic hydrocarbons (PAHs) in grilled meats and tobacco smoke, undergo metabolism to reactive intermediates that may form mutation-inducing DNA adducts in the colorectum. Heme iron in red meat may contribute to oxidative DNA damage and endogenous NOC formation. However, the chemicals involved in colorectal DNA damage and the paradigms of CRC etiology remain unproven. There is a critical need to establish physicochemical methods for identifying and quantitating DNA damage induced by genotoxicants in the human colorectum. We established robust nano-liquid chromatography/high-resolution accurate mass Orbitrap tandem mass spectrometry (LC/HRAMS2) methods to measure DNA adducts of nine meat and tobacco-associated carcinogens and lipid peroxidation products in the liver, colon, and rectum of carcinogen-treated rats employing fresh-frozen and formalin-fixed paraffin-embedded (FFPE) tissues. Some NOCs form O6-carboxymethyl-2'-deoxyguanosine, O6-methyl-2'-deoxyguanosine, and unstable quaternary N-linked purine/pyrimidine adducts, which generate apurinic/apyrimidinic (AP) sites. AP sites were quantitated following derivatization with O-(pyridin-3-yl-methyl)hydroxylamine. DNA adduct quantitation was conducted with stable isotope-labeled internal standards, and method performance was validated for accuracy and reproducibility. Limits of quantitation ranged from 0.1 to 1.1 adducts per 108 bases using 3 µg of DNA. Adduct formation in animals ranged from ∼1 in 108 to ∼1 in 105 bases, occurring at comparable levels in fresh-frozen and FFPE specimens for most adducts. AP sites increased by 25- to 75-fold in the colorectum and liver, respectively. Endogenous lipid peroxide-derived 3-(2-deoxy-ß-d-erythro-pentofuranosyl)pyrimido[1,2-α]purin-10(3H)-one (M1dG) and 6-oxo-M1dG adduct levels were not increased by carcinogen dosing but increased in FFPE tissues. Human biomonitoring studies can implement LC/HRAMS2 assays for DNA adducts and AP sites outlined in this work to advance our understanding of CRC etiology.

Model simulation and mechanism of Fe(0/II/III) cycle activated persulfate degradation of methylparaben based on hydroxylamine enhanced nano-zero-valent iron.

The mechanism of Fe2+-activated peroxodisulfate (PDS) by hydroxylamine (HA) has been investigated, however, nano zero-valent iron-activated persulfate (nZVI/PDS) has a more optimal effect and needs further investigation. This study investigated the addition of HA to nZVI/PDS to improve Fe2+ regeneration and accelerate methylparaben (MP) degradation by Fe (0/II/III) cycle. After 60 min of reaction, the HA-enhanced nZVI/PDS (HA/nZVI/PDS) system afforded a 21% increase in MP degradation, reaching 93.26% (1 mM HA, 1 mM nZVI, and 2 mM PDS). nZVI/PDS system was a second-order reaction, but after adding HA, the reaction was more suitable for the first-order reaction. The addition of HA effectively promoted the reduction of Fe3+ to Fe2+ to improve the effect and reaction rate of PDS degradation of MP (k increased from 0.0127 min-1 to 0.0198 min-1) and broadened the reaction pH range. The results of various characterizations of nZVI before and after the reaction revealed that nZVI changed from a spherical structure to a bundle structure and was slightly oxidized. Changes in the Fe2+ and Fe3+ concentrations as well as in the pH of the reaction systems were monitored and the possible reactions of the HA/nZVI/PDS system were derived for the first time (knZVI/PDS<3.7 × 106 M-1 s-1, kFe3+/NH2O· >4.2 min-1). 12 potential compounds were investigated and MP breakdown pathways were speculated; hydroxylation was determined to be the most important pathway of degradation. And the HA/nZVI/PDS system had universal applicability.

Novel biodegradable molecularly imprinted polymer nanoparticles for drug delivery of methotrexate anti-cancer; synthesis, characterization and cellular studies.

BACKGROUND: Recently biodegradable nanoparticles are the center of attention for the development of drug delivery systems. Molecularly imprinted polymer (MIP) is an interesting candidate for designing drug nano-carriers. MIP-based nanoparticles could be used for cancer treatment and exhibited the potential to fill gaps regarding to ligand-based nanomaterials. Also, the presence of a cross-linker can play an essential role in nanoparticle stability and physicochemical properties of nanoparticles after synthesis. OBJECTIVES: In this research, a biodegradable drug delivery system based on MIP nanoparticles was prepared using a biodegradable cross-linker (dimethacryloyl hydroxylamine, DMHA) for methotrexate (MTX). A hydrolysable functional group CO-O-NH-CO was added to the crosslinking agent to increase the final biodegradability of the polymer. METHODS: Firstly, a biodegradable cross-linker was synthesized. Then, the non-imprinted polymers were prepared through mini-emulsion polymerization in the absence of a template; and efficient particle size distribution was determined. Finally, methotrexate was placed in imprinted polymers to achieve the desired MIP. Different types of MIPs were synthesized using different molar ratios of template, cross-linker, and functional monomer, and the optimal molar ratio was obtained at 1:4:20, respectively. RESULTS: HNMR successfully confirmed the chemical structure of the cross-linker. According to SEM images, nanoparticles had a spherical shape with a smooth surface. The imprinted nanoparticles showed a narrow size distribution with an average of 120 nm at a high ratio of cross-linker. The drug loading and entrapment efficiency were 6.4% and 92%, respectively. The biodegradability studies indicated that the nanoparticles prepared by DMHA had a more degradability rate than ethylene glycol dimethacrylate as a conventional cross-linker. Also, the polymer degradation rate was higher in alkaline environments. Release studies in physiological and alkaline buffer showed an initial burst release of a quarter of loaded MTX during the day and a 70% release during a week. The Korsmeyer-Peppas model described the release pattern. The cytotoxicity of MTX loaded in nanoparticles was studied on the MCF-7 cell line, and the IC50 was 3.54 µg/ml. CONCLUSION: It was demonstrated that nanoparticles prepared by DMHA have the potential to be used as biodegradable drug carriers for anticancer delivery. Synthesis schema of molecular imprinting of methotrexate in biodegradable polymer based on dimethacryloyl hydroxylamine cross-linker, for use as nanocarrier anticancer delivery to breast tumor.

Screening of Organic Acidurias by Gas Chromatography-Mass Spectrometry (GC-MS).

Organic acidurias or acidemias are a group of diverse disorders caused by decreased or diminished activity of specific enzyme or transporter involved in the metabolism of amino acids, carbohydrates, fatty acids, and nucleic acids. Organic acidurias are generally inherited but may be acquired due to deficiency of certain cofactors or vitamins. As clinical symptoms are of nonspecific nature, definitive diagnosis of organic aciduria requires measurement of organic acids in urine or blood and sometimes enzyme activity in the cells. Gas chromatography-mass spectrometry (GC-MS) is a commonly used method for screening of organic acidurias.GC-MS procedure described here involves the use of urine volume that contains 1 µmole (113 µg) of creatinine. Internal standards (tropic and 2-ketocaproic acids) are added to the samples, followed by treatment with hydroxylamine to form oxime derivatives of the ketoacids. The mixture is then acidified, and organic acids are extracted in ethyl acetate. The organic extract is concentrated to dryness, and the residue is treated with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA)/trimethylchlorosilane (TMCS)/pyridine to form the trimethylsilyl (TMS) derivatives of the organic acids. The derivatized extract is then directly injected onto GC-MS for analysis.