Displaying all 13 publications

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  1. Ang CW, Tan L, Qu Z, West NP, Cooper MA, Popat A, et al.
    ACS Biomater Sci Eng, 2022 Oct 10;8(10):4196-4206.
    PMID: 34464089 DOI: 10.1021/acsbiomaterials.1c00807
    Pretomanid and MCC7433, a novel nitroimidazopyrazinone analog, are promising antitubercular agents that belong to the bicyclic nitroimidazole family. Despite possessing high cell permeability, they suffer from poor aqueous solubility and require specialized formulations in order to be orally bioavailable. To address this limitation, we investigated the use of mesoporous silica nanoparticles (MCM-41) as drug carriers. MCM-41 nanoparticles were synthesized using a sol-gel method, and their surface was further modified with amine and phosphonate groups. A simple rotary evaporation method was used to incorporate the compounds of interest into the nanoparticles, leading to a high encapsulation efficiency of ≥86% with ∼10% loading (w/w). An overall significant improvement of solubility was also observed, and the pharmacological activity of pretomanid and MCC7433 was fully retained when tested in vitro against Mycobacterium tuberculosis using these nanocarriers. Amino-functionalized MCM-41 nanoparticles were found to enhance the systemic exposure of MCC7433 in mice (1.3-fold higher Cmax) compared to MCC7433 alone. The current work highlights the potential of using nanoparticles such as mesoporous silica as a carrier for oral delivery of poorly soluble antibacterial agents against tuberculosis.
    Matched MeSH terms: Organophosphonates*
  2. Naidu KR, Kumar KS, Arulselvan P, Reddy CB, Lasekan O
    Arch Pharm (Weinheim), 2012 Dec;345(12):957-63.
    PMID: 23015406 DOI: 10.1002/ardp.201200192
    A series of α-hydroxyphosphonates were synthesized from the reaction of aldehyde (1) with triethylphosphite (2) in the presence of oxone and evaluated for their antioxidant properties against lipid peroxidation, reduced glutathione, superoxide dismutase, and catalase. The majority of the compounds showed promising antioxidant activity. Diethyl anthracen-9-yl (hydroxy) methylphosphonate (3n) is the most potent and biologically active compound against free radicals.
    Matched MeSH terms: Organophosphonates/chemical synthesis*; Organophosphonates/pharmacology; Organophosphonates/chemistry
  3. Shinde R, Halim N, Banerjee AK
    J AOAC Int, 2020 Nov 01;103(6):1528-1533.
    PMID: 33247748 DOI: 10.1093/jaoacint/qsaa066
    BACKGROUND: Glyphosate and glufosinate are broad-spectrum herbicides which are frequently used in palm oil plantations for weed control. Metabolites of these herbicides are known to have environmental and food safety implications. As there is no validated method for multiresidue testing of these herbicides and their metabolites in palm oil products, a new method was needed for the purpose of regulatory analysis.

    OBJECTIVE: In this study, we endeavored to develop a rapid method for multiresidue analysis of glyphosate (+aminomethylphosphonic acid) and glufosinate (+3-methylphosphinicopropionic acid and N-acetyl-glufosinate) in refined and crude palm oil matrices using liquid chromatography (LC) tandem mass spectrometry (MS/MS).

    METHOD: The optimized sample preparation workflow included extraction of refined or crude palm oil (10 g) with acidified water (0.1 M HCl), cleanup by phase separation with dichloromethane, and analysis by LC-MS/MS with multiple reaction monitoring.

    RESULTS: The use of a Torus-DEA LC column ensured simultaneous analysis of these compounds within a runtime of 10 min. The LOQ of these analytes was 0.01 mg/kg, except that of aminomethylphosphonic acid which was 0.02 mg/kg. The method sensitivity complied with the national maximum residue limits of Malaysia and the European Union. Also, the method selectivity, sensitivity, accuracy, and precision were aligned with the SANTE/12682/2019 guidelines of analytical quality control.

    CONCLUSIONS: The potentiality of the optimized method lies in a high throughput direct analysis of glyphosate and glufosinate with their metabolites in a single chromatographic run. The method is fit for purpose for regulatory testing of these residues in a broad range of palm oil matrices.

    HIGHLIGHTS: The study reports for the first time a validated method for simultaneous analysis of glyphosate, glufosinate, and their metabolites in a range of palm oil products. The method did not require a derivatization step and provided a high throughput analysis of these compounds with satisfactory selectivity, sensitivity, accuracy, and precision.

    Matched MeSH terms: Organophosphonates
  4. See HH, Hauser PC, Ibrahim WA, Sanagi MM
    Electrophoresis, 2010 Jan;31(3):575-82.
    PMID: 20119968 DOI: 10.1002/elps.200900380
    Rapid and direct online preconcentration followed by CE with capacitively coupled contactless conductivity detection (CE-C(4)D) is evaluated as a new approach for the determination of glyphosate, glufosinate (GLUF), and aminophosphonic acid (AMPA) in drinking water. Two online preconcentration techniques, namely large volume sample stacking without polarity switching and field-enhanced sample injection, coupled with CE-C(4)D were successfully developed and optimized. Under optimized conditions, LODs in the range of 0.01-0.1 microM (1.7-11.1 microg/L) and sensitivity enhancements of 48- to 53-fold were achieved with the large volume sample stacking-CE-C(4)D method. By performing the field-enhanced sample injection-CE-C(4)D procedure, excellent LODs down to 0.0005-0.02 microM (0.1-2.2 microg/L) as well as sensitivity enhancements of up to 245- to 1002-fold were obtained. Both techniques showed satisfactory reproducibility with RSDs of peak height of better than 10%. The newly established approaches were successfully applied to the analysis of glyphosate, glufosinate, and aminophosphonic acid in spiked tap drinking water.
    Matched MeSH terms: Organophosphonates/analysis*
  5. See HH, Hauser PC, Sanagi MM, Ibrahim WA
    J Chromatogr A, 2010 Sep 10;1217(37):5832-8.
    PMID: 20696433 DOI: 10.1016/j.chroma.2010.07.054
    A dynamic supported liquid membrane tip extraction (SLMTE) procedure for the effective extraction and preconcentration of glyphosate (GLYP) and its metabolite aminomethylphosphonic acid (AMPA) in water has been investigated. The SLMTE procedure was performed in a semi-automated dynamic mode and demonstrated a greater performance against a static extraction. Several important extraction parameters such as donor phase pH, cationic carrier concentration, type of membrane solvent, type of acceptor stripping phase, agitation and extraction time were comprehensively optimized. A solution of Aliquat-336, a cationic carrier, in dihexyl ether was selected as the supported liquid incorporated into the membrane phase. Quantification of GLYP and AMPA was carried out using capillary electrophoresis with contactless conductivity detection. An electrolyte solution consisting of 12 mM histidine (His), 8 mM 2-(N-morpholino)ethanesulfonic acid (MES), 75 microM cetyltrimethylammonium bromide (CTAB), 3% methanol, pH 6.3, was used as running buffer. Under the optimum extraction conditions, the method showed good linearity in the range of 0.01-200 microg/L (GLYP) and 0.1-400 microg/L (AMPA), acceptable reproducibility (RSD 5-7%, n=5), low limits of detection of 0.005 microg/L for GLYP and 0.06 microg/L for AMPA, and satisfactory relative recoveries (90-94%). Due to the low cost, the SLMTE device was disposed after each run which additionally eliminated the possibility of carry-over between runs. The validated method was tested for the analysis of both analytes in spiked tap water and river water with good success.
    Matched MeSH terms: Organophosphonates/analysis*; Organophosphonates/chemistry
  6. Hassan M, Baig AA, Attique SA, Abbas S, Khan F, Zahid S, et al.
    Daru, 2021 Jun;29(1):73-84.
    PMID: 33537864 DOI: 10.1007/s40199-020-00384-3
    PURPOSE: To predict potential inhibitors of alpha-enolase to reduce plasminogen binding of Streptococcus pneumoniae (S. pneumoniae) that may lead as an orally active drug. S. pneumoniae remains dominant in causing invasive diseases. Fibrinolytic pathway is a critical factor of S. pneumoniae to invade and progression of disease in the host body. Besides the low mass on the cell surface, alpha-enolase possesses significant plasminogen binding among all exposed proteins.

    METHODS: In-silico based drug designing approach was implemented for evaluating potential inhibitors against alpha-enolase based on their binding affinities, energy score and pharmacokinetics. Lipinski's rule of five (LRo5) and Egan's (Brain Or IntestinaL EstimateD) BOILED-Egg methods were executed to predict the best ligand for biological systems.

    RESULTS: Molecular docking analysis revealed, Sodium (1,5-dihydroxy-2-oxopyrrolidin-3-yl)-hydroxy-dioxidophosphanium (SF-2312) as a promising inhibitor that fabricates finest attractive charges and conventional hydrogen bonds with S. pneumoniae alpha-enolase. Moreover, the pharmacokinetics of SF-2312 predict it as a therapeutic inhibitor for clinical trials. Like SF-2312, phosphono-acetohydroxamate (PhAH) also constructed adequate interactions at the active site of alpha-enolase, but it predicted less favourable than SF-2312 based on binding affinity.

    CONCLUSION: Briefly, SF-2312 and PhAH ligands could inhibit the role of alpha-enolase to restrain plasminogen binding, invasion and progression of S. pneumoniae. As per our investigation and analysis, SF-2312 is the most potent naturally existing inhibitor of S. pneumoniae alpha-enolase in current time.

    Matched MeSH terms: Organophosphonates/pharmacokinetics; Organophosphonates/chemistry
  7. Poh F, Sing WH, Mohan PC
    Med J Malaysia, 2015 Feb;70(1):38-41.
    PMID: 26032529
    We present a case of a 53-year-old woman who developed multifocal insufficiency fractures associated with adefovir dipivoxil (ADV) induced osteomalacia, including recurring metatarsal insufficiency fractures and a subtrochanteric femoral insufficiency fracture requiring surgical fixation. She had received low-dose ADV treatment for 59 months for chronic hepatitis B viral infection at the time of presentation with subtrochanteric fracture. Imaging evidence of multifocal insufficiency fractures and metabolic disease on background of hypophosphatemia is attributed to hypophosphatemic osteomalacia from adefovir-induced renal proximal tubular dysfunction. Radiologists and clinicians should be aware of the possibility of insufficiency fractures in patients receiving ADV therapy to avoid delayed diagnosis and progression of high-risk proximal femoral fractures.
    Matched MeSH terms: Organophosphonates
  8. Saad B, Kanapathy K, Ahmad MN, Hussin AH, Ismail Z
    Talanta, 1991 Dec;38(12):1399-402.
    PMID: 18965315
    Three main types of PVC solvent polymeric membrane ion-selective electrodes for chloroquine are described. They are based on three ion-pairing agents namely dipicrylamine (DPA), tetraphenylborate (TPB) or tetrakis(4-chlorophenyl)borate (TCPB) with either dioctylphenyl phosphonate (DOPP) or trioctyl phosphate (TOP) solvent mediator. All electrodes exhibit Nernstian responses, fast dynamic response times and a wide useful pH range. The best all-round electrode is based on TPB and TOP plasticizing solvent mediators with a limit of detection of 7.1 x 10(-6)M and was utilized for the assay of chloroquine in tablets. Direct potentiometric determinations with either the analyte addition method or the normal calibration method gave results comparable to the official method.
    Matched MeSH terms: Organophosphonates
  9. Kim HP, Vasilopoulou M, Ullah H, Bibi S, Ximim Gavim AE, Macedo AG, et al.
    Nanoscale, 2020 Apr 14;12(14):7641-7650.
    PMID: 32207472 DOI: 10.1039/c9nr10745b
    Organo-metal halide perovskite field-effect transistors present serious challenges in terms of device stability and hysteresis in the current-voltage characteristics. Migration of ions located at grain boundaries and surface defects in the perovskite film are the main reasons for instability and hysteresis issues. Here, we introduce a perovskite grain molecular cross-linking approach combined with amine-based surface passivation to address these issues. Molecular cross-linking was achieved through hydrogen bond interactions between perovskite halogens and dangling bonds present at grain boundaries and a hydrophobic cross-linker, namely diethyl-(12-phosphonododecyl)phosphonate, added to the precursor solution. With our approach, we obtained smooth and compact perovskite layers composed of tightly bound grains hence significantly suppressing the generation and migration of ions. Moreover, we achieved efficient surface passivation of the perovskite films upon surface treatment with an amine-bearing polymer, namely polyethylenimine ethoxylated. With our synergistic grain and surface passivation approach, we were able to demonstrate the first perovskite transistor with a complete lack of hysteresis and unprecedented stability upon continuous operation under ambient conditions. Added to the merits are its ambipolar transport of opposite carriers with balanced hole and electron mobilities of 4.02 and 3.35 cm2 V-1 s-1, respectively, its high Ion/Ioff ratio >104 and the lowest sub-threshold swing of 267 mV dec-1 reported to date for any perovskite transistor. These remarkable achievements obtained through a cost-effective molecular cross-linking of grains combined with amine-based surface passivation of the perovskite films open a new era and pave the way for the practical application of perovskite transistors in low-cost electronic circuits.
    Matched MeSH terms: Organophosphonates
  10. Leung N
    Med J Malaysia, 2005 Jul;60 Suppl B:22-7.
    PMID: 16108169
    Nucleot(s)ide analogues are making milestones in the treatment of chronic hepatitis B (CHB) as safe oral therapy. FDA approved lamivudine in adult patients in 1998, adefovir dipivoxil in 2002, and entecavir in March 2005. Lamivudine is effective in viral suppression, ALT normalization, and improvement in histology in both HBeAg positive and HBeAg negative / HBV DNA positive patients. HBeAg seroconversion rates correlate directly with pretreatment ALT levels at 18-30% after one year of therapy. Hepatitis flares may occur if lamivudine is stopped before HBeAg seroconversion. Lamivudine resistant YMDD mutants emerge at a rate of 15-20% per year of therapy; often associated with the rebound viraemia, relapse of hepatitis or even hepatic decompensation. Durability of response off lamivudine therapy is not satisfactory and may be dependent on duration of therapy post-seroconversion. Lamivudine is well tolerated with few serious adverse events, even in patients with decompensated cirrhosis. Long term therapy in viraemic patients with advanced fibrosis or cirrhosis delays clinical progression. Adefovir dipivoxil is an oral prodrug of adefovir. 10 mg daily is effective in suppressing both wild-type HBV and YMDD mutants, normalising ALT and improving histology. Adefovir dipivoxil has been shown to be well tolerated in longterm therapy. Renal toxicity reported in higher dosages is rarely seen except among patients with creatinine clearance less than 50 ml/min. Adefovir resistance may emerge and the overall rate is much lower than lamivudine, reaching 18% after 4 years of therapy. Adefovir-resistant mutants (rt N236T) are susceptible to lamivudine and entecavir. Little data is available for durability of response off therapy. Entecavir is an oral nucleoside analogue with a recommended dosage of 0.5 mg daily for nucleoside-naive patients, and 1 mg daily for lamivudine-refractory patients. It is a potent antiviral and may also reduced intrahepatitic cccDNA. Entecavir resistance so far has only been detected in lamivudine resistant patients in the one-year studies. Patient counseling is very important to decide on the choice among available therapeutic options. The assessment of the risks/benefits of each option should be carefully explained to individual patient.
    Matched MeSH terms: Organophosphonates/therapeutic use*
  11. Boettiger DC, Saphonn V, Lee MP, Phanuphak P, Pham TT, Heng Sim BL, et al.
    J Acquir Immune Defic Syndr, 2014 Dec 01;67(4):e131-3.
    PMID: 25197829 DOI: 10.1097/QAI.0000000000000338
    Matched MeSH terms: Organophosphonates/adverse effects*
  12. Leung AK, Barankin B, Leong KF, Hon KL
    Drugs Context, 2018;7:212563.
    PMID: 30622585 DOI: 10.7573/dic.212563
    Background: Penile warts are the most common sexually transmitted disease in males. Clinicians should be familiar with the proper evaluation and management of this common condition.

    Objective: To provide an update on the current understanding, evaluation, and management of penile warts.

    Methods: A PubMed search was completed in Clinical Queries using the key terms 'penile warts' and 'genital warts'. The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews.

    Results: Penile warts are caused by human papillomavirus (HPV), notably HPV-6 and HPV-11. Penile warts typically present as asymptomatic papules or plaques. Lesions may be filiform, exophytic, papillomatous, verrucous, hyperkeratotic, cerebriform, fungating, or cauliflower-like. Approximately one-third of penile warts regress without treatment and the average duration prior to resolution is approximately 9 months. Active treatment is preferable to watchful observation to speed up clearance of the lesions and to assuage fears of transmission and autoinoculation. Patient-administered therapies include podofilox (0.5%) solution or gel, imiquimod 3.75 or 5% cream, and sinecatechins (polypheron E) 15% ointment. Clinician-administered therapies include podophyllin, cryotherapy, bichloroacetic or trichloroacetic acid, oral cimetidine, surgical excision, electrocautery, and carbon dioxide laser therapy. Patients who do not respond to first-line treatments may respond to other therapies or a combination of treatment modalities. Second-line therapies include topical/intralesional/intravenous cidofovir, topical 5-fluorouracil, and topical ingenol mebutate.

    Conclusion: No single treatment has been shown to be consistently superior to other treatment modalities. The choice of the treatment method should depend on the physician's comfort level with the various treatment options, the patient's preference and tolerability of treatment, and the number and severity of lesions. The comparative efficacy, ease of administration, adverse effects, cost, and availability of the treatment modality should also be taken into consideration.

    Matched MeSH terms: Organophosphonates
  13. Naing C, Poovorawan Y, Tong KS
    BMC Infect Dis, 2018 Nov 14;18(1):564.
    PMID: 30428847 DOI: 10.1186/s12879-018-3506-x
    BACKGROUND: There are randomized trials assessing a variety of antiviral drugs for hepatitis B virus (HBV), but the relative effectiveness of these drugs in the treatment of patients co-infected with human immunodeficiency virus (HIV) remains unclear. The objectives of the current study were to estimate and rank the relative effectiveness of antiviral drugs for treating HBV and HIV co-infected patients.

    METHODS: Randomized trials, assessing the efficacy of antiviral drugs for HBV and HIV co-infected patients were searched in health-related databases. The methodological quality of the included trials was evaluated using the Cochrane risk of bias tool. Main outcome in this meta-analysis study was the success of treatment by antivirals as determined by virologic response. We performed pairwise and network meta-analysis of these trials and assessed the quality of evidence using the GRADE approach.

    RESULTS: Seven randomized trials (329 participants) were included in this network meta-analysis study. A network geometry was formed with six treatment options including four antiviral drugs, adefovir (ADV), emtricitabine (FTC), lamivudine (LMV) and tenofovir disoproxil fumarate (TDF), combination treatment of TDF plus LMV, and placebo. The weighted percentage contributions of each comparison distributed fairly equally in the entire network of evidence. An assumption of consistency required for network meta-analysis was not violated (the global Wald test for inconsistency: Chi2(4) = 3.63, p = 0.46). The results of estimates showed no differences between the treatment regimens in terms of viral response for treating HBV and HIV co-infected patients, which spanned both benefit and harm (e.g. LMV vs TDF plus LMV: OR: 0.37, 95%CI: 0.06-2.41). Overall, the certainty of evidence was very low in all comparisons (e.g. LMV vs TDF plus LMV: 218 fewer per 1000,121 more to 602 fewer, very low certainty). Therefore, we remained uncertain to the true ranking of the antiviral treatments in HBV/ HIV co-infected patients.

    CONCLUSIONS: The findings suggest that the evidence is insufficient to provide guidance to the relative effectiveness of currently available antiviral drugs with dual activity in treating co-infection of HBV/HIV. Well-designed, large clinical trials in this field to address other important outcomes from different epidemiological settings are recommended.

    Matched MeSH terms: Organophosphonates
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