Displaying publications 61 - 80 of 422 in total

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  1. Mahesparan VA, Bin Abd Razak FS, Ming LC, Uddin AH, Sarker MZI, Bin LK
    Int J Pharm Compd, 2020 3 21;24(2):148-155.
    PMID: 32196477
    Orodispersible tablets disintegrate rapidly (within 3 minutes) in the oral cavity and release the medicament before swallowing. The mode of disintegrant addition might affect the properties of orodispersible tablets. The objective of this study was to formulate and evaluate orodispersible tablets by studying different modes of disintegration addition with varying concentrations of disintegrants. The wet granulation method was used to produce the orodispersible tablets. Two methods of disintegration addition were compared (i.e., intragranular, extragranular). Three disintegrants (i.e., cornstarch, sodium starch glycolate, crospovidone) were used at three levels (5%, 10%, and 15%) in the study. The formulations were tested for the powder flowability (angle of repose) and characterized physically (hardness, weight, thickness, friability, disintegration time). The mangosteen pericarp extract was used as a model active pharmaceutical ingredient to be incorporated into the optimum formulation. It was observed that the extragranular method produced granules with better flowability compared to that of the intragranular method. Crospovidone was found as the most efficient disintegrant among the three. The optimum formulation selected was one with the highest concentration of crospovidone (15%), which showed the fastest disintegration time. The mode of disintegrant addition into the orodispersible tablets formulation was found to show a marked difference in the disintegration, as well as other physical characteristics of the orodispersible tablets where the extragranular mode of addition showed better property, which caused the orodispersible tablets to disintegrate the fastest.
    Matched MeSH terms: Solubility
  2. Azmi NHS, Ming LC, Uddin ABMH, Sarker ZI, Bin LK
    Int J Pharm Compd, 2022 1 27;26(1):80-87.
    PMID: 35081048
    Oral drug delivery has been recognized as the most desirable drug administration method among other drug delivery routes due to its ease of administration, long shelf life, and low cost. Orally disintegrating tablets disintegrate within seconds in the mouth without the need of water for swallowing. This unique feature of orally disintegrating tablets is favorable to special populations such as geriatric and pediatric patients. Formulation optimization is significant to obtain the optimal combination of tablet constituents, as the tablet composition is influential on dosage-form characteristics. The objective of this study was to investigate the effect of different types of fillers and percentage on the physical properties of orally disintegrating tablets by using amlodipine as the model drug. Blank orally disintegrating tablets containing different fillers, namely, Sorbolac 400, Granulac 200, and CombiLac with different percentages, were prepared using the wet granulation method and were evaluated based on weight variation, hardness, thickness, friability, and disintegration time. Formulation 5 that consists of 25% Granulac 200 showed the optimal result among all formulations with the fastest disintegration time (96.17 s Å} 18.40) and sufficient tablet hardness (4.59 kg Å} 0.70). Hence, formulation 5 was selected as the optimal formulation and incorporated with amlodipine. From this study, it can be concluded that excipients have an essential role in determining the physical properties of orally disintegrating tablets.
    Matched MeSH terms: Solubility
  3. Amirmoshiri M, Zhang L, Puerto MC, Tewari RD, Bahrim RZBK, Farajzadeh R, et al.
    Langmuir, 2020 Sep 01.
    PMID: 32870010 DOI: 10.1021/acs.langmuir.0c01521
    We investigate the dynamic adsorption of anionic surfactant C14 - 16 alpha olefin sulfonate on Berea sandstone cores with different surface wettability and redox states under high temperature that represents reservoir conditions. Surfactant adsorption levels are determined by analyzing the effluent history data with a dynamic adsorption model assuming Langmuir isotherm. A variety of analyses, including surface chemistry, ionic composition, and chromatography, is performed. It is found that the surfactant breakthrough in the neutral-wet core is delayed more compared to that in the water-wet core because the deposited crude oil components on the rock surface increase the surfactant adsorption via hydrophobic interactions. As the surfactant adsorption is satisfied, the crude oil components are solubilized by surfactant micelles and some of the adsorbed surfactants are released from the rock surface. The released surfactant dissolves in the flowing surfactant solution, thereby resulting in an overshoot of the produced surfactant concentration with respect to the injection value. Furthermore, under water-wet conditions, changing the surface redox potential from an oxidized to a reduced state decreases the surfactant adsorption level by 40%. We find that the decrease in surfactant adsorption is caused not only by removing the iron oxide but also by changing the calcium concentration after the core restoration process (calcite dissolution and ion exchange as a result of using EDTA). Findings from this study suggest that laboratory surfactant adsorption tests need to be conducted by considering the wettability and redox state of the rock surface while recognizing how core restoration methods could significantly alter the ionic composition during surfactant flooding.
    Matched MeSH terms: Solubility
  4. Md Ramli SH, Wong TW, Naharudin I, Bose A
    Carbohydr Polym, 2016 Nov 05;152:370-381.
    PMID: 27516284 DOI: 10.1016/j.carbpol.2016.07.021
    Conventional alginate pellets underwent rapid drug dissolution and failed to exert colon targeting unless subjected to complex coating. This study designed coatless delayed-release oral colon-specific alginate pellets for ulcerative colitis treatment. Alginate pellets, formulated with water-insoluble ethylcellulose and various calcium salts, were prepared using solvent-free melt pelletization technique which prevented reaction between processing materials during agglomeration and allowed reaction to initiate only in dissolution. Combination of acid-soluble calcium carbonate and highly water-soluble calcium acetate did not impart colon-specific characteristics to pellets due to pore formation in fragmented matrices. Combination of moderately water-soluble calcium phosphate and calcium acetate delayed drug release due to rapid alginate crosslinking by soluble calcium from acetate salt followed by sustaining alginate crosslinking by calcium phosphate. The use of 1:3 ethylcellulose-to-alginate enhanced the sustained drug release attribute. The ethylcellulose was able to maintain the pellet integrity without calcium acetate. Using hydrophobic prednisolone as therapeutic, hydrophilic alginate pellets formulated with hydrophobic ethylcellulose and moderately polar calcium phosphate exhibited colon-specific in vitro drug release and in vivo anti-inflammatory action. Coatless oral colon-specific alginate pellets can be designed through optimal formulation with melt pelletization as the processing technology.
    Matched MeSH terms: Solubility
  5. Karim S, Baie SH, Hay YK, Bukhari NI
    Pak J Pharm Sci, 2014 May;27(3):425-38.
    PMID: 24811797
    Pelletized dosage forms can be prepared by different methods which, in general, are time consuming and labor intensive. The current study was carried out to investigate the feasibility of preparing the spherical pellets of omeprazole by sieving-spheronization. An optimized formulation was also prepared by extrusion-spheronization process to compare the physical parameters between these two methods. The omeprazole pellets were consisted of microcrystalline cellulose, polyvinylpyrrolidone K 30, sodium lauryl sulphate and polyethylene glycol 6000. The omeprazole delay release system was developed by coating the prepared pellets with aqueous dispersion of Kollicoat 30 DP. The moisture content, spheronization speed and residence time found to influence the final properties of omeprazole pellets prepared by extrusion-spheronization and sieving-spheronization. The Mann-Whitney test revealed that both methods produced closely similar characteristics of the pellets in terms of, friability (p=0.553), flowability (p=0.677), hardness (p=0.103) and density (bulk, p=0.514, tapped, p=0.149) except particle size distribution (p=0.004). The percent drug release from the coated formulation prepared by sieving-spheronization and extrusion spheronization was observed to be 84.12 ± 1.10% and 82.67 ± 0.96%, respectively. Dissolution profiles of both formulations were similar as indicated by values of f1 and f2, 1.52 and 89.38, respectively. The coated formulation prepared by sieving-spheronization and commercial reference product, Zimore ® also showed similar dissolution profiles (f1=1.22, f2=91.52). The pellets could be prepared using sieving-spheronization. The process is simple, easy, less time- and labor-consuming and economical as compared to extrusion-spheronization process.
    Matched MeSH terms: Solubility
  6. Zeeshan F, Bukhari NI
    AAPS PharmSciTech, 2010 Jun;11(2):910-6.
    PMID: 20496016 DOI: 10.1208/s12249-010-9456-2
    Modified-release multiple-unit tablets of loratadine and pseudoephedrine hydrochloride with different release profiles were prepared from the immediate-release pellets comprising the above two drugs and prolonged-release pellets containing only pseudoephedrine hydrochloride. The immediate-release pellets containing pseudoephedrine hydrochloride alone or in combination with loratadine were prepared using extrusion-spheronization method. The pellets of pseudoephedrine hydrochloride were coated to prolong the drug release up to 12 h. Both immediate- and prolonged-release pellets were filled into hard gelatin capsule and also compressed into tablets using inert tabletting granules of microcrystalline cellulose Ceolus KG-801. The in vitro drug dissolution study conducted using high-performance liquid chromatography method showed that both multiple-unit capsules and multiple-unit tablets released loratadine completely within a time period of 2 h, whereas the immediate-release portion of pseudoephedrine hydrochloride was liberated completely within the first 10 min of dissolution study. On the other hand, the release of pseudoephedrine hydrochloride from the prolonged release coated pellets was prolonged up to 12 hr and followed zero-order release kinetic. The drug dissolution profiles of multiple-unit tablets and multiple-unit capsules were found to be closely similar, indicating that the integrity of pellets remained unaffected during the compression process. Moreover, the friability, hardness, and disintegration time of multiple-unit tablets were found to be within BP specifications. In conclusion, modified-release pellet-based tablet system for the delivery of loratadine and pseudoephedrine hydrochloride was successfully developed and evaluated.
    Matched MeSH terms: Solubility
  7. Kuang TK, Kang YB, Segarra I, Kanwal U, Ahsan M, Bukhari NI
    Turk J Pharm Sci, 2021 04 20;18(2):167-175.
    PMID: 33902255 DOI: 10.4274/tjps.galenos.2020.48902
    Objectives: This study was conducted to assess the effect of microwave heating on the preparation of paracetamol cross-linked gelatin matrices by using the design of experiment (DoE) approach and explore the influence of the duration of microwave irradiation, the concentrations of crosslinker, and the amount of sodium bicarbonate (salt) on paracetamol release. These parameters were also compared with those of the matrices prepared via conventional heating.

    Materials and Methods: Twenty gel matrices were prepared with different durations of microwave irradiation, amounts of maize, and concentrations of sodium bicarbonate as suggested by Design Expert (DX®). The percentage drug release, the coefficient of variance (CV) in release, and the mean dissolution time (MDT) were the properties explored in the designed experimentation.

    Results: Target responses were dependent on microwave irradiation time, cross-linker amount, and salt concentration. Classical and microwave heating did not demonstrate statistically significant difference in modifying the percentage of drug released from the matrices. However, the CVs of microwave-assisted formulations were lower than those of the gel matrices prepared via classical heating. Thus, microwave heating produced lesser variations in drug release. The optimized gel matrices demonstrated that the observed percentage of drug release, CV, and MDT were within the prediction interval generated by DX®. The release mechanism of the matrix formulations followed the Peppas-Korsmeyer anomalous transport model.

    Conclusion: The DoE-supported microwave-assisted approach could be applied to optimize the critical factors of drug release with less variation.

    Matched MeSH terms: Solubility
  8. Mohd Faiz Nasruddin, Theocharospoulos, Antonios, Ray, Noel, Burke, Francis M.
    MyJurnal
    Fitting accuracy of dental prostheses is essential for clinical success. An ideal marginal and internal fit will minimize plaque accumulation, gingival irritation, cement dissolution and micro leakage as well as enhancing the mechanical behaviour of a fixed partial denture (FPD) (1). Unfortunately, there is disagreement about acceptable marginal and internal fit discrepancies of FPD’s (2) from 75-200μm. There are two main manufacturing routes of CAD/CAM FPD’s: the subtractive and the additive route. The subtractive route is a top-down approach which involves milling the desired article out of a block of the material of choice using a series of burs. This route is currently the most common CAD/CAM technique for the fabrication of metal alloy FPD’s. The additive route is a bottom-up approach where the desired article is fabricated layer by layer out of the material of choice. Examples include selective laser sintering and selective laser melting for metal alloy FPD’s.
    Matched MeSH terms: Solubility
  9. Chik MW, Hussain Z, Zulkefeli M, Tripathy M, Kumar S, Majeed ABA, et al.
    Drug Deliv Transl Res, 2019 04;9(2):578-594.
    PMID: 29594914 DOI: 10.1007/s13346-018-0505-9
    Carbon nanotubes (CNTs) possess outstanding properties that could be useful in several technological, drug delivery, and diagnostic applications. However, their unique physical and chemical properties are hindered due to their poor solubility. This article review's the different ways and means of solubility enhancement of single-wall carbon nanotubes (SWNTs). The advantages of SWNTs over the multi-walled carbon nanotubes (MWNTs) and the method of non-covalent modification for solubility enhancement has been the key interest in this review. The review also highlights a few examples of dispersant design. The review includes some interesting utility of SWNTs being wrapped with polymer especially in biological media that could mediate proper drug delivery to target cells. Further, the use of wrapped SWNTs with phospholipids, nucleic acid, and amphiphillic polymers as biosensors is of research interest. The review aims at summarizing the developments relating to wrapped SWNTs to generate further research prospects in healthcare.
    Matched MeSH terms: Solubility
  10. Zakiyah, L.K., Gui, M.M., Foo, R.S., Mohamed, A.R., Chai, S.P.
    ASM Science Journal, 2011;5(2):91-100.
    MyJurnal
    The functionalization of pristine CNTs is necessary for carbon nanotubes (CNTs) to be fully utilized, with the aim of increasing the nanotube reactivity and solubility in aqueous solutions. In this study, multi-walled carbon nanotubes (MWCNTs) were functionalized with a carboxylic group as this was an important step prior to application. The carboxylic group-functionalization was conducted through acid treatment, using sulphuric and nitric acids mixed at a ratio of 3:1 (v/v) and sonication for 30 min under different temperatures and time durations. The functionalization conditions of 50ºC x 5 h and 60ºC x 3 h were identified to be most suitable for introducing a carboxylic group onto the nanotube surfaces. The percentage of total weight loss due to the carboxylic group on the MWCNTs treated at 50ºC x 5 h and 60ºC x 3 h obtained from the thermogravimetric analysis was 13.26% and 13.76%, respectively. For both samples, peaks corresponding to the carboxylic group were identified in the FT-IR spectra. The changes in the morphology of the treated MWCNTs were also observed under SEM analysis.
    Matched MeSH terms: Solubility
  11. Low BS, Teh CH, Yuen KH, Chan KL
    Nat Prod Commun, 2011 Mar;6(3):337-41.
    PMID: 21485270
    A simple validated LC-UV method for the phytochemical analysis of four bioactive quassinoids, 13alpha(21)-epoxyeurycomanone (EP), eurycomanone (EN), 13alpha,21-dihydroeurycomanone (ED) and eurycomanol (EL) in rat plasma following oral (200 mg/kg) and intravenous administration (10 mg/kg) of a standardized extract Fr 2 of Eurycoma longifolia Jack was developed for pharmacokinetic and bioavailability studies. The extract Fr 2 contained 4.0%, 18.5%, 0.7% and 9.5% of EP, EN, ED and EL, respectively. Following intravenous administration, EP displayed a relatively longer biological half-life (t1/2 = 0.75 +/- 0.25 h) due primarily to its lower elimination rate constant (k(e)) of 0.84 +/- 0.26 h(-1)) when compared with the t1/2 of 0.35 +/- 0.04 h and k(e) of 2.14 +/- 0.27 h(-1), respectively of EN. Following oral administration, EP showed a higher C(max) of 1.61 +/- 0.41 microg/mL over that of EN (C(max) = 0.53 +/- 0.10 microg/mL). The absolute bioavailability of EP was 9.5-fold higher than that of EN, not because of chemical degradation since both quassinoids were stable at the simulated gastric pH of 1. Instead, the higher log K(ow) value of EP (-0.43) contributed to greater membrane permeability over that of EN (log K(ow) = -1.46) at pH 1. In contrast, EL, being in higher concentration in the extract than EP, was not detected in the plasma after oral administration because of substantial degradation by the gastric juices after 2 h. Similarly, ED, being unstable at the acidic pH and together with its low concentration in Fr 2, was not detectable in the rat plasma. In conclusion, upon oral administration of the bioactive standardized extract Fr 2, EP and EN may be the only quassinoids contributing to the overall antimalarial activity; this is worthy of further investigation.
    Matched MeSH terms: Solubility
  12. Teoh XY, Goh CF, Aminu N, Chan SY
    J Pharm Biomed Anal, 2021 Jan 05;192:113631.
    PMID: 33011581 DOI: 10.1016/j.jpba.2020.113631
    Atovaquone (ATQ) is a poorly soluble drug. Therefore, formulating ATQ into its supersaturated state through solid dispersion for bioavailability enhancement can be of great value. However, due to fast crystallising properties of ATQ, the quantification of ATQ in a supersaturated solid dispersion system can be complicated. Therefore, in pursuit of accurate quantification of such sample, a simple HPLC analytical method utilising a C18 column (250 × 4.6 mm ID, 5 μm) for the quantitation of ATQ has been developed and validated. Atovaquone elution using the proposed method demonstrated a retention time around 7.6 min with good linearity (R2 > 0.999). The system suitability is also detailed with the tailing factor at 1.365 ± 0.002. The addition of solubilising agent as sample treatment step aided in ensuring the accurate quantitation of the fast crystallising ATQ. The developed HPLC quantitation method has been successfully employed in the analysis of ATQ from solid dispersion samples in in vitro dissolution as well as ex vivo permeation studies for formulation development.
    Matched MeSH terms: Solubility
  13. Teoh XY, Bt Mahyuddin FN, Ahmad W, Chan SY
    Pharm Dev Technol, 2020 Feb;25(2):245-251.
    PMID: 31690150 DOI: 10.1080/10837450.2019.1689401
    Poor solubility and bioavailability of drugs are often affected by its microscopic structural properties. Nitrofurantoin (NF), a Biopharmaceutics Classification System class II item, has a low water solubility with low plasma concentrations. To improve its therapeutic efficacy, formulation strategy of solid dispersion (SD) and co-crystallization are compared herein. The co-crystal is prepared with citric acid in 1:1 stoichiometric ratio while SD consists of 30% w/w nitrofurantoin and 70% w/w hydroxypropyl methylcellulose (HPMC) as the carrier system. As a control, the physical mixture of NF and HPMC was prepared. All the preparations were characterized with differential scanning calorimetry (DSC), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), microscopy analysis, solubility, and dissolution studies. The formation of co-crystal, solvent evaporated, and spray-dried SD are confirmed by the ATR-FTIR where peaks shifting of several functional groups indicate the formation of the hydrogen bond. Dissolution studies showed a greater initial dissolution rate in co-crystal than SD despite the possible presence of amorphous content in the SD system. Overall, co-crystal is concluded to be a better approach than SD for an effective dissolution.
    Matched MeSH terms: Solubility/drug effects
  14. Teoh XY, Yeoh Y, Yoong LK, Chan SY
    Pharm Res, 2020 Jan 07;37(2):28.
    PMID: 31912250 DOI: 10.1007/s11095-019-2734-0
    PURPOSE: This study aims to conduct an impact investigation in the hydrophobic-hydrophilic balance as an important factor for dissolution improvement of a hydrophilic carrier-based solid dispersion system.

    METHODS: Polymeric carriers with different hydrophobic to hydrophilic ratios were used to prepare several electrospun solid dispersion formulations. Physicochemical properties and surface morphology of the samples were assessed using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR), polarized light microscopy, Differential Scanning Calorimetry (DSC), X-ray Powder Diffraction (XRPD) and Scanning Electron Microscopy (SEM). Dissolution study was conducted in a non-sink condition to assess the drug release.

    RESULTS: Incorporation of a higher amount of hydrophilic component showed an improvement in formulating a fully amorphous system based on XRPD, yet the dissolution rate increment showed no significant difference from the lower. Hence, the degree of crystallinity is proven not to be the crucial factor contributing to dissolution rate improvement. The presence of a concomitant hydrophobic component, however, showed ability in resisting precipitation and sustaining supersaturation.

    CONCLUSION: Hydrophobicity in a binary carrier system plays an important role in achieving and maintaining the supersaturated state particularly for an amorphous solid dispersion. Graphical Abstract.

    Matched MeSH terms: Solubility
  15. Kyaw Oo M, Mandal UK, Chatterjee B
    Pharm Dev Technol, 2017 Feb;22(1):2-12.
    PMID: 26616399 DOI: 10.3109/10837450.2015.1116568
    High melting point polymeric carrier without plasticizer is unacceptable for solid dispersion (SD) by melting method. Combined polymer-plasticizer carrier significantly affects drug solubility and tableting property of SD.
    Matched MeSH terms: Solubility
  16. Al-Japairai KAS, Alkhalidi HM, Mahmood S, Almurisi SH, Doolaanea AA, Al-Sindi TA, et al.
    ACS Omega, 2020 Dec 22;5(50):32466-32480.
    PMID: 33376884 DOI: 10.1021/acsomega.0c04588
    Telmisartan suffers from low oral bioavailability due to its poor water solubility. The research work presents a formulation of solid dispersed (SD) telmisartan formulation as a ternary mixture of a drug, a polymeric carrier (poly(vinylpyrrolidone) (PVP) K30), and an alkalizer (Na2CO3). The preparation method, which was lyophilization of an aqueous solution containing the ingredients, was free from any organic solvent. The developed SD formulations resulted in a significant improvement in in vitro dissolution (>90% drug dissolution in 15 min) compared to pure telmisartan. Solid-state characterization by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) studies indicated the conversion of crystalline telmisartan into an amorphous form. Fourier transform infrared (FTIR) spectroscopy revealed the drug-polymer interaction that was responsible for reducing the chances of recrystallization. A short-term stability study showed that selected SD formulations were stable in terms of in vitro dissolution and retained their amorphous structure in ambient and accelerated conditions over 2 months. Selected formulations (drug/PVP K30/Na2CO3 as 1:1:2 or 1:2:2 weight ratio) resulted in >2.48 times relative oral bioavailability compared to marketed formulations. It was considered that the incorporation of an alkalizer and a hydrophilic polymer, and amorphization of telmisartan by lyophilization, could enhance in vitro dissolution and improve oral bioavailability.
    Matched MeSH terms: Solubility
  17. Chan SY, Toh SM, Khan NH, Chung YY, Cheah XZ
    Drug Dev Ind Pharm, 2016 Nov;42(11):1800-1812.
    PMID: 27049232
    Solution-mediated transformation has been cited as one of the main problems that deteriorate dissolution performances of solid dispersion (SD). This is mainly attributed by the recrystallization tendency of poorly soluble drug. Eventually, it will lead to extensive agglomeration which is a key process in reducing the dissolution performance of SD and offsets the true benefit of SD system. Here, a post-processing treatment is suggested in order to reduce the recrystallization tendency and hence bring forth the dissolution advantage of SD system.
    Matched MeSH terms: Solubility
  18. Ng PQ, Ling LSC, Chellian J, Madheswaran T, Panneerselvam J, Kunnath AP, et al.
    Curr Pharm Des, 2020;26(36):4580-4590.
    PMID: 32520681 DOI: 10.2174/1381612826666200610111013
    Many plant-based bioactive compounds have been serving as the origin of drugs since long ago and many of them have been proven to have medicinal value against various chronic diseases, including, cancer, arthritis, hepatic diseases, type-2 diabetes and cardiovascular diseases. However, their clinical applications have been limited due to their poor water solubility, stability, low bioavailability and extensive transformation due to the first-pass metabolism. The applications of nanocarriers have been proven to be able to improve the delivery of bioactive phytoconstituents, resulting in the enhancement of various pharmacokinetic properties and thereby increasing the therapeutic value of phytoconstituents. These biocompatible nanocarriers also exert low toxicity to healthy cells. This review focuses on the uses and applications of different types of nanocarriers to enhance the delivery of phytoconstituents for the treatment of various chronic diseases, along with comparisons related to bioavailability and therapeutic efficacy of nano phytoconstituents with native phytoconstituents.
    Matched MeSH terms: Solubility
  19. Li Y, Qin T, Ingle T, Yan J, He W, Yin JJ, et al.
    Arch Toxicol, 2017 Jan;91(1):509-519.
    PMID: 27180073 DOI: 10.1007/s00204-016-1730-y
    In spite of many reports on the toxicity of silver nanoparticles (AgNPs), the mechanisms underlying the toxicity are far from clear. A key question is whether the observed toxicity comes from the silver ions (Ag(+)) released from the AgNPs or from the nanoparticles themselves. In this study, we explored the genotoxicity and the genotoxicity mechanisms of Ag(+) and AgNPs. Human TK6 cells were treated with 5 nM AgNPs or silver nitrate (AgNO3) to evaluate their genotoxicity and induction of oxidative stress. AgNPs and AgNO3 induced cytotoxicity and genotoxicity in a similar range of concentrations (1.00-1.75 µg/ml) when evaluated using the micronucleus assay, and both induced oxidative stress by measuring the gene expression and reactive oxygen species in the treated cells. Addition of N-acetylcysteine (NAC, an Ag(+) chelator) to the treatments significantly decreased genotoxicity of Ag(+), but not AgNPs, while addition of Trolox (a free radical scavenger) to the treatment efficiently decreased the genotoxicity of both agents. In addition, the Ag(+) released from the highest concentration of AgNPs used for the treatment was measured. Only 0.5 % of the AgNPs were ionized in the culture medium and the released silver ions were neither cytotoxic nor genotoxic at this concentration. Further analysis using electron spin resonance demonstrated that AgNPs produced hydroxyl radicals directly, while AgNO3 did not. These results indicated that although both AgNPs and Ag(+) can cause genotoxicity via oxidative stress, the mechanisms are different, and the nanoparticles, but not the released ions, mainly contribute to the genotoxicity of AgNPs.
    Matched MeSH terms: Solubility
  20. Hooi Poay T, Sui Kiong L, Cheng Hock C
    Phytochem Anal, 2011 Nov-Dec;22(6):516-25.
    PMID: 21495106 DOI: 10.1002/pca.1312
    Phyllagathis rotundifolia (Jack) Bl. (Melastomataceae) is a creeping herb found in Peninsular Malaysia and Sumatra. Traditionally, a decoction of the leaves is used in the treatment of malaria, fever and stomach ache.
    Matched MeSH terms: Solubility
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