Displaying publications 1 - 20 of 61 in total

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  1. Hyperosmolar nonketotic diabetic coma
    Tan BY, Cheah JS, Tan SK, Chew BK
    Med J Malaya, 1970 Jun;24(4):308-10.
    PMID: 4248355
    Matched MeSH terms: Osmolar Concentration
  2. Fulltext Responses to salinity in the littoral earthworm genus Pontodrilus
    Seesamut T, Ng B, Sutcharit C, Chanabun R, Panha S
    Sci Rep, 2022 Dec 24;12(1):22304.
    PMID: 36566279 DOI: 10.1038/s41598-022-26099-w
    The cosmopolitan littoral earthworm Pontodrilus litoralis is distributed in tropical and sub-tropical coastal habitats, whereas P. longissimus is reported only in the Thai-Malay coastal line. In the present study, we examined the difference in salinity effect on the survival rate, wet weight (hereafter weight) change, behaviour, and osmolality of these two Pontodrilus species. A 28 d exposure to varying salinity concentration (0-50 ppt) revealed that P. litoralis is able to survive over a wide salinity range than P. longissimus, with the latter species exhibiting a low survival rate over the same salinity range. During short-term exposure (0-96 h) to a salinity of less than 30 ppt, P. litoralis exhibited weight gain and this was significant in the first 12 h of exposure. However, P. longissimus gained weight when exposed to salinity at under 10 ppt in the first 72 h of exposure. The two species of Pontodrilus behaved differently when exposed to different salinities. The coelomic fluid osmolarity of Pontodrilus was related to the exposure medium and was mostly maintained as hyperosmotic to the external medium over the range of salinities tested. This study shows how two different species of the littoral earthworm genus Pontodrilus respond to a change in salinity, which may explain their dispersal pattern and shape their distribution pattern throughout Southeast Asia.
    Matched MeSH terms: Osmolar Concentration
  3. Downstream protein separation by surfactant precipitation: a review
    Wong FWF, Ariff AB, Stuckey DC
    Crit Rev Biotechnol, 2018 Feb;38(1):31-46.
    PMID: 28427287 DOI: 10.1080/07388551.2017.1312266
    In a conventional protein downstream processing (DSP) scheme, chromatography is the single most expensive step. Despite being highly effective, it often has a low process throughput due to its semibatch nature, sometimes with nonreproducible results and relatively complex process development. Hence, more work is required to develop alternative purification methods that are more cost-effective, but exhibiting nearly comparable performance. In recent years, surfactant precipitation has been heralded as a promising new method for primary protein recovery that meets these criteria and is a simple and cost-effective method that purifies and concentrates. The method requires the direct addition of a surfactant to a complex solution (e.g. a fermentation broth) containing the protein of interest, where the final surfactant concentration is maintained below its critical micelle concentration (CMC) in order to allow for electrostatic and hydrophobic interactions between the surfactant and the target protein. An insoluble (hydrophobic) protein-surfactant complex is formed and backextraction of the target protein from the precipitate into a new aqueous phase is then carried out using either solvent extraction, or addition of a counter-ionic surfactant. Importantly, as highlighted by past researchers, the recovered proteins maintain their activity and structural integrity, as determined by circular dichroism (CD). In this review, various aspects of surfactant precipitation with respect to its general methodology and process mechanism, system parameters influencing performance, protein recovery, process selectivity and process advantages will be highlighted. Moreover, comparisons will be made to reverse micellar extraction, and the current drawbacks/challenges of surfactant precipitation will also be discussed. Finally, promising directions of future work with this separation technique will be highlighted.
    Matched MeSH terms: Osmolar Concentration
  4. Characterization and absorbing properties of oil palm empty fruit bunch filled poly (acrylic acid–co–acrylamide) superabsorbent polymer composites
    Nor Erma Shuhadah Abdul Razak, Shahrir Hashim, Abdul Razak Rahmat
    Sains Malaysiana, 2011;40:1179-1186.
    Oil palm empty fruit bunch graft poly (acrylic acid-co-acrylamide) superabsorbent composite (OPEFB-g-(PAA-co-PAM) SAPC) was synthesized by graft copolymerization of the acrylic acid (AA) and acrylamide (AM) comonomer onto OPEFB fibre using ammonium persulfate (APS) and N,N-methylene bisacarylamide (MBA) as an initiator and crosslinker, respectively. The absorbency in various chloride salt solutions indicated that the absorbency decreased with increasing ionic strength of the salt solutions. Moreover, the absorbency under load (AUL) of SAPC was investigated at various applied loading and results show that, AUL decreased with increasing applied loading. Infrared Spectroscopy (IR) and Thermogravimetric Analysis (TGA) were carried out to confirm the chemical structure and thermal properties of the synthesized superabsorbent, respectively.
    Matched MeSH terms: Osmolar Concentration
  5. TRANSCRIPTOMIC ANALYSIS OF GRACILARIA CHANGII (RHODOPHYTA) IN RESPONSE TO HYPER- AND HYPOOSMOTIC STRESSES(1)
    Teo SS, Ho CL, Teoh S, Rahim RA, Phang SM
    J Phycol, 2009 Oct;45(5):1093-9.
    PMID: 27032354 DOI: 10.1111/j.1529-8817.2009.00724.x
    Osmotic stress is one of the most significant natural abiotic stresses that occur in the intertidal zones. Seaweeds may physiologically acclimate to changing osmolarity by altering their transcriptome. Here, we investigated the transcriptomic changes of Gracilaria changii (B. M. Xia et I. A. Abbott) I. A. Abbott, J. Zhang et B. M. Xia in response to hyper- and hypoosmotic stresses using a cDNA microarray approach. Microarray analysis revealed that 199 and 200 genes from ∼3,300 genes examined were up- and down-regulated by >2-fold in seaweed samples treated at 50 parts per thousand (ppt) artificial seawater (ASW) compared with those at 30 ppt ASW, respectively. The number of genes that were up- and down-regulated by >2-fold in seaweed samples treated at 10 ppt ASW compared with those at 30 ppt ASW were 154 and 187, respectively. A majority of these genes were only differentially expressed under hyper- or hypoosmotic conditions, whereas 67 transcripts were affected by both stresses. The findings of this study have shed light on the expression profiles of many transcripts during the acclimation of G. changii to hyperosmotic and hypoosmotic conditions. This information may assist in the prioritization of genes to be examined in future studies.
    Matched MeSH terms: Osmolar Concentration
  6. Fulltext Comparative Analysis on Dielectric Gold and Aluminium Triangular Junctions: Impact of Ionic Strength and Background Electrolyte by pH Variations
    Letchumanan I, Md Arshad MK, Gopinath SCB, Rajapaksha RDAA, Balakrishnan SR
    Sci Rep, 2020 Apr 22;10(1):6783.
    PMID: 32321969 DOI: 10.1038/s41598-020-63831-w
    Field of generating a surface thin film is emerging broadly in sensing applications to obtain the quick and fast results by forming the high-performance sensors. Incorporation of thin film technologies in sensor development for the better sensing could be a promising way to attain the current requirements. This work predominantly delineates the fabrication of the dielectric sensor using two different sensing materials (Gold and Aluminium). Conventional photolithography was carried out using silicon as a base material and the photo mask of the dielectric sensor was designed by AutoCAD software. The physical characterization of the fabricated sensor was done by Scanning Electron Microscope, Atomic Force Microscope, High Power Microscope and 3D-nano profiler. The electrical characterization was performed using Keithley 6487 picoammeter with a linear sweep voltage of 0 to 2 V at 0.01 V step voltage. By pH scouting, I-V measurements on the bare sensor were carried out, whereby the gold electrodes conducts a least current than aluminium dielectrodes. Comparative analysis with pH scouting reveals that gold electrode is suitable under varied ionic strengths and background electrolytes, whereas aluminium electrodes were affected by the extreme acid (pH 1) and alkali (pH 12) solutions.
    Matched MeSH terms: Osmolar Concentration
  7. Molecular forces governing protein-protein interaction: Structure-function relationship of complexes protein in the food industry
    Alrosan M, Tan TC, Easa AM, Gammoh S, Alu'datt MH
    Crit Rev Food Sci Nutr, 2021 Jan 18.
    PMID: 33455424 DOI: 10.1080/10408398.2021.1871589
    The application of protein-protein interaction (PPI) has been widely used in various industries, such as food, nutraceutical, and pharmaceutical. A deeper understanding of PPI is needed, and the molecular forces governing proteins and their interaction must be explained. The design of new structures with improved functional properties, e.g., solubility, emulsion, and gelation, has been fueled by the development of structural and colloidal building blocks. In this review, the molecular forces of protein structures are discussed, followed by the relationship between molecular force and structure, ways of a bind of proteins together in solution or at the interface, and functional properties. A more detailed look is thus taken at the relationship between the various influencing factors on molecular forces involved in PPI. These factors include protein properties, such as types, concentration, and mixing ratio, and solvent conditions, such as ionic strength and pH. This review also summarizes methods tha1t are capable of identifying molecular forces in protein and PPI, as well as characterizing protein structure.
    Matched MeSH terms: Osmolar Concentration
  8. Gender discrimination in the influence of hyperglycemia and hyperosmolarity on rat aortic tissue responses to insulin
    Wong NL, Achike FI
    Regul. Pept., 2010 Aug 9;163(1-3):113-9.
    PMID: 20434492 DOI: 10.1016/j.regpep.2010.04.003
    Hyperglycaemia initiates endothelial dysfunction causing diabetic macro- and micro-vasculopathy, the main causes of morbidity and mortality in diabetes mellitus. The vasculopathy exhibits gender peculiarities. We therefore explored gender differences in comparing the effects of hyperglycaemia (50 mM) per se with its hyperosmolar (50 mM) effects on vascular tissue responses to insulin. Endothelium-intact or denuded thoracic aortic rings from age-matched male and female Sprague-Dawley rats were incubated for 10 min or 6 h (acute versus chronic exposure) in normal, hyperglycaemic or hyperosmolar Krebs solution. Relaxant responses to insulin (6.9x10(-7)-6.9x10(-5) M) of the phenylephrine-contracted tissues were recorded. Endothelium denudation in both genders inhibited relaxation to insulin in all conditions, more significantly in female than in male tissues, suggesting the female response to insulin is more endothelium-dependent than the male. Acutely and chronically exposed normoglycemic endothelium-intact or -denuded tissues responded similarly to insulin. Chronic hyperglycemic or hyperosmolar exposure did not alter the endothelium-denuded tissue responses to insulin, whereas the responses of the endothelium-intact male and female hyperosmolar, and male hyperglycemic tissues were enhanced. The results show that insulin exerts an endothelium-dependent and independent relaxation with the female tissue responses more endothelium-dependent than the male. The data also suggest that hyperosmolarity per se enhances aortic tissue relaxant responses to insulin whereas hyperglycemia per se inhibits the same and more so in female than male tissues. These effects are endothelium-dependent.
    Matched MeSH terms: Osmolar Concentration*
  9. Bovine serum albumin: survival and osmolarity effect in bovine spermatozoa stored above freezing point
    Nang CF, Osman K, Budin SB, Ismail MI, Jaffar FH, Mohamad SF, et al.
    Andrologia, 2012 May;44 Suppl 1:447-53.
    PMID: 21806660 DOI: 10.1111/j.1439-0272.2011.01203.x
    Liquid nitrogen preservation in remote farms is a limitation. The goal of this study was to determine optimum temperature above freezing point for bovine spermatozoa preservation using bovine serum albumin (BSA) as a supplementation. Pooled semen sample from three ejaculates was subjected to various BSA concentration (1, 4, 8 and 12 mg ml(-1)), before incubation in different above freezing point temperatures (4, 25 and 37 °C). Viability assessment was carried out against time from day 0 (fresh sample) until all spermatozoa become nonviable. Optimal condition for bovine spermatozoa storage was at 4 °C with 1 mg ml(-1) BSA for almost 7 days. BSA improved bovine spermatozoa viability declining rate to 44.28% at day 4 and 57.59% at day 7 compared to control, with 80.54% and 98.57% at day 4 and 7 respectively. Increase in BSA concentration did not improve sperm viability. Our results also confirmed that there was a strong negative correlation between media osmolarity and bovine spermatozoa survival rate with r = 0.885, P < 0.0001. Bovine serum albumin helps to improve survival rate of bovine spermatozoa stored above freezing point.
    Matched MeSH terms: Osmolar Concentration
  10. Geospeciation of arsenic using MINTEQA2 for a post-mining lake
    Sari SA, Ujang Z, Ahmad UK
    Water Sci Technol, 2006;54(11-12):289-99.
    PMID: 17302332
    The objective of this study was to investigate the cycling of arsenic in the water column of a post-mining lake. This study is part of a research project to develop health risk assessment for the surrounding population. Inductively Coupled Plasma-Mass Spectrophotometer (ICP-MS) and Capillary Electrophoresis (CE) have been used to analyze the total amount and speciation, respectively. A computer program, called MINTEOA2, which was developed by the United States Environmental Protection Agency (USEPA) was used for predicting arsenic, iron, and manganese as functions of pH and solubility. Studying the pH values and cycle of arsenic shows that the percentage of bound arsenate, As(V) species in the form of HAsO4- increases with range pH from 5 to 7, as well as Fe(II) and Mn(III). As expected phases of arsenic oxides are FeAsO4 and Mn3(AsO4), as a function of solubility, however none of these phases are over saturated and not precipitated. It means that the phases of arsenic oxides have a high solubility.
    Matched MeSH terms: Osmolar Concentration
  11. Fulltext Ultraviolet-visible study on acid-base equilibria of aporphine alkaloids with antiplasmodial and antioxidant activities from Alseodaphne corneri and Dehaasia longipedicellata
    Zahari A, Ablat A, Omer N, Nafiah MA, Sivasothy Y, Mohamad J, et al.
    Sci Rep, 2016;6:21517.
    PMID: 26898753 DOI: 10.1038/srep21517
    The UV-vis spectra of isocorydine 1, norisocorydine 2 and boldine 3 were studied in 2% v/v acetonitrile, at constant ionic strength (0.1 M NaCl, 35 degree Celsius). The pK(a) values of isocorydine 1 and norisocorydine 2 were 11.75 and 12.07, respectively. Boldine 3 gave a pK(a) value of 9.16 and 10.44. All of the alkaloids 1-3 were stable at physiological pH; thereby all of them will not ionize, thus permitting the basic nitrogen to be protonated and accumulated within the acidic food vacuole of Plasmodium via pH trapping. Subsequently, acidic food vacuoles that have been neutralized by alkaloids would result in enhancement of the antiplasmodial activity. The alkaloids showed antiplasmodial activity against Plasmodium falciparum and antioxidant activities; DPPH radical scavenging, metal chelating and ferric reducing power. The antioxidant properties of the alkaloids under investigation revealed that in addition to the antiplasmodial activity, the alkaloids can also prevent oxidative damage. It can be prevented by binding free heme and neutralizing the electrons produced during the Plasmodium falciparum mediated haemoglobin destruction in the host. Slightly basic properties of the aforementioned alkaloids, along with their antioxidant activities, are advantageous in improving the suppression of malaria infection that cause less damage to the host.
    Matched MeSH terms: Osmolar Concentration
  12. Fulltext Neuropsychiatric manifestations of osmotic demyelination syndrome secondary to overcorrection of severe hyponatraemia in hyperemesis gravidarum: a case report
    Sim Mervyn Ian, Nor Zuraida Zainal, Aili Hanim
    Malaysian Journal of Psychiatry, 2018;27(2):0-0.
    MyJurnal
    Osmotic demyelination syndrome (ODS) may occur as a consequence of a
    rapid change in serum osmolality. We report a case of a 32-year-old woman
    who presented to the hospital with symptoms suggestive of severe
    hyperemesis gravidarum. Blood investigation results showed that patient had
    severe hyponatraemia (serum sodium 109 mmol/L) and hypokalaemia
    (serum potassium 1.7 mmol/L). Active and vigorous corrections to these
    electrolyte imbalances had led to an overly increased of serum sodium levels
    within a short duration of time. Four days after the rapid correction, patient
    started exhibiting neuropsychiatric manifestations. Radiological findings
    were consistent with the diagnosis of ODS. The neuropsychiatric symptoms
    experienced by patient gradually worsened with time. Subsequently,
    intravenous methylprednisolone was administered to patient. Patient showed
    marked response to the steroid given. At the time of discharge, twenty-seven
    days later, patient had recovered from most of the neuropsychiatric sequelae;
    but still required assistance during ambulation. In conclusion, correction of
    electrolyte imbalances should be done in a more judicious manner. Prudent
    corrections of electrolyte alterations could have possibly prevented the onset
    of ODS and its’ devastating neuropsychiatric sequelae in this patient.
    Matched MeSH terms: Osmolar Concentration
  13. Rigid membranes of Malayan ovalocytes: a likely genetic barrier against malaria
    Mohandas N, Lie-Injo LE, Friedman M, Mak JW
    Blood, 1984 Jun;63(6):1385-92.
    PMID: 6722355
    A high frequency of nonhemolytic hereditary ovalocytosis in Malayan aborigines is thought to result from reduced susceptibility of affected individuals to malaria. Indeed, Kidson et al. recently showed that ovalocytes from Melanesians in Papua New Guinea are resistant to infection in culture by the malarial parasite Plasmodium falciparum. In order to determine if protection against parasitic invasion in these ovalocytes might be the result of some altered membrane material property in these unusual cells, we measured their membrane and cellular deformability characteristics using an ektacytometer . Ovalocytic red cells were found to be much less deformable in comparison to normal discoid red cells. Similar measurements on isolated membrane preparations revealed a marked reduction in ovalocytic membrane deformability. To produce equal deformation of ovalocytic and normal membranes, ovalocytes required an 8-10-fold increase in applied shear stress, indicating that their membrane was capable of deforming under sufficient stress. To test the possibility that this increased membrane rigidity might confer resistance to parasitic invasion, we performed an in vitro invasion assay using Plasmodium falciparum merozoites and Malayan ovalocytes of varying deformability from seven different donors. The level of infection of the ovalocytes ranged from 1% to 35% of that in control cells, and the extent of inhibition appeared to be closely related to the reduction in membrane deformability. Moreover, we were able to induce similar resistance to parasitic invasion in nonovalocytic normal red cells by increasing their membrane rigidity with graded exposure to a protein crosslinking agent. Our findings suggest that resistance to parasite invasion of Malayan ovalocytes is the result of a genetic mutation that causes increased membrane rigidity.
    Matched MeSH terms: Osmolar Concentration
  14. Fulltext Effect of Aging, Antioxidant, and Mono- and Divalent Ions at High Temperature on the Rheology of New Polyacrylamide-Based Co-Polymers
    Akbari S, Mahmood SM, Tan IM, Ling OL, Ghaedi H
    Polymers (Basel), 2017 Oct 04;9(10).
    PMID: 30965788 DOI: 10.3390/polym9100480
    The viscosity of four new polymers was investigated for the effect of aging at high temperature, with varying degrees of salinity and hardness. The four sulfonated based polyacrylamide co-polymers were FLOCOMB C7035; AN132 VHM; SUPERPUSHER SAV55; and THERMOASSOCIATIF copolymers. All polymer samples were aged at 80 °C for varying times (from zero to at least 90 days) with and without isobutyl alcohol (IBA) as an antioxidant. To see the effect of divalent ions on the polymer solution viscosity, parallel experiments were performed in a mixture of CaCl₂-NaCl of the same ionic strength as 5 wt % NaCl. The polymers without IBA showed severe viscosity reduction after aging for 90 days in both types of preparation (5 wt % NaCl or CaCl₂-NaCl). In the presence of IBA, viscosity was increased when aging time was increased for 5 wt % NaCl. In CaCl₂-NaCl, on the other hand, a viscosity reduction was observed as aging time was increased. This behavior was observed for all polymers except AN132 VHM.
    Matched MeSH terms: Osmolar Concentration
  15. In vivo and in vitro depolymerizations of intracellular medium-chain-length poly-3-hydroxyalkanoates produced by Pseudomonas putida Bet001
    Anis SNS, Mohamad Annuar MS, Simarani K
    Prep Biochem Biotechnol, 2017 Sep 14;47(8):824-834.
    PMID: 28635367 DOI: 10.1080/10826068.2017.1342266
    In vivo and in vitro depolymerizations of intracellular medium-chain-length poly-3-hydroxyalkanoates (mcl-PHA) in Pseudomonas putida Bet001 grown on lauric acid was studied. Both processes were studied under optimum conditions for mcl-PHA depolymerization viz. 0.2 M Tris-HCl buffer, pH 9, ionic strength (I) = 0.2 M at 30°C. For in vitro depolymerization studies, cell-free system was obtained from lysing bacterial cells suspension by ultrasonication at optimum conditions (frequency 37 kHz, 30% of power output, <25°C for 120 min). The comparison between in vivo and in vitro depolymerizations of intracellular mcl-PHA was made. In vitro depolymerization showed lower depolymerization rate but higher yield compared to in vivo depolymerization. The monomer liberation rate reflected the mol% distribution of the initial polymer subunit composition, and the resulting direct individual products of depolymerization were identical for both in vivo and in vitro processes. It points to exo-type reaction for both processes, and potential biological route to chiral molecules.
    Matched MeSH terms: Osmolar Concentration
  16. Fulltext Physiological effects of thermal stress on red hybrid tilapia
    Nadirah Musa, Najiah Musa, Hazza Roshada Ramli, Tajuddin Abd Manaf
    Journal of Engineering and Science Research, 2017;1(2):27-32.
    MyJurnal
    Exposure to any type of stressors either environmental, chemical or perceived stressors, results in a series of physiological responses in animals. The purpose of this study was to investigate the effects of thermal stress on physiological responses in red hybrid tilapia. Adult red hybrid tilapia were previously exposed to gradual increment of water temperature in thermoregulated recirculating tanks at a rate of 1oC/8 h from 28 to 31oC and kept for 1, 7 and 14 days. Cortisol, HMG-CoA reductase, total protein and osmolality were determined. Plasma cortisol and HMG-CoA levels were significantly increased in the heat-stressed groups compared to nonstressed groups. Osmolality was also significantly higher (p
    Matched MeSH terms: Osmolar Concentration
  17. Fulltext Application of Biochar Derived From Pyrolysis of Waste Fiberboard on Tetracycline Adsorption in Aqueous Solution
    Xu D, Gao Y, Lin Z, Gao W, Zhang H, Karnowo K, et al.
    Front Chem, 2019;7:943.
    PMID: 32117859 DOI: 10.3389/fchem.2019.00943
    In this study, biochars derived from waste fiberboard biomass were applied in tetracycline (TC) removal in aqueous solution. Biochar samples were prepared by slow pyrolysis at 300, 500, and 800°C, and were characterized by ultimate analysis, Fourier transform infrared (FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), etc. The effects of ionic strength (0-1.0 mol/L of NaCl), initial TC concentration (2.5-60 ppm), biochar dosage (1.5-2.5 g/L), and initial pH (2-10) were systemically determined. The results present that biochar prepared at 800°C (BC800) generally possesses the highest aromatization degree and surface area with abundant pyridinic N (N-6) and accordingly shows a better removal efficiency (68.6%) than the other two biochar samples. Adsorption isotherm data were better fitted by the Freundlich model (R2 is 0.94) than the Langmuir model (R2 is 0.85). Thermodynamic study showed that the adsorption process is endothermic and mainly physical in nature with the values of ΔH0 being 48.0 kJ/mol, ΔS0 being 157.1 J/mol/K, and ΔG0 varying from 1.02 to -2.14 kJ/mol. The graphite-like structure in biochar enables the π-π interactions with a ring structure in the TC molecule, which, together with the N-6 acting as electron donor, is the main driving force of the adsorption process.
    Matched MeSH terms: Osmolar Concentration
  18. An efficient biosorption-based dispersive liquid-liquid microextraction with extractant removal by magnetic nanoparticles for quantification of bisphenol A in water samples by gas chromatography-mass spectrometry detection
    Subuhi NEAM, Saad SM, Zain NNM, Lim V, Miskam M, Kamaruzaman S, et al.
    J Sep Sci, 2020 Aug;43(16):3294-3303.
    PMID: 32519432 DOI: 10.1002/jssc.201901194
    In this work, a simple, fast, sensitive, and environmentally friendly method was developed for preconcentration and quantitative measurement of bisphenol A in water samples using gas chromatography with mass spectrometry. The preconcentration approach, namely biosorption-based dispersive liquid-liquid microextraction with extractant removal by magnetic nanoparticles was performed based on the formation of microdroplet of rhamnolipid biosurfactant throughout the aqueous samples, which accelerates the mass transfer process between the extraction solvent and sample solution. The process is then followed by the application of magnetic nanoparticles for easy retrieval of the analyte-containing extraction solvent. Several important variables were optimized comprehensively including type of disperser solvent and desorption solvent, rhamnolipid concentration, volume of disperser solvent, amount of magnetic nanoparticles, extraction time, desorption time, ionic strength, and sample pH. Under the optimized microextraction and gas chromatography with mass spectrometry conditions, the method demonstrated good linearity over the range of 0.5-500 µg/L with a coefficient of determination of R2  = 0.9904, low limit of detection (0.15 µg/L) and limit of quantification (0.50 µg/L) of bisphenol A, good analyte recoveries (84-120%) and acceptable relative standard deviation (1.8-14.9%, n = 6). The proposed method was successfully applied to three environmental water samples, and bisphenol A was detected in all samples.
    Matched MeSH terms: Osmolar Concentration
  19. Characterisation, in-vitro and in-vivo evaluation of valproic acid-loaded nanoemulsion for improved brain bioavailability
    Tan SF, Kirby BP, Stanslas J, Basri HB
    J Pharm Pharmacol, 2017 Nov;69(11):1447-1457.
    PMID: 28809443 DOI: 10.1111/jphp.12800
    OBJECTIVE: This study was aimed to investigate the potential of formulated valproic acid-encapsulated nanoemulsion (VANE) to improve the brain bioavailability of valproic acid (VPA).

    METHODS: Valproic acid-encapsulated nanoemulsions were formulated and physically characterised (osmolarity, viscosity, drug content, drug encapsulation efficiency). Further investigations were also conducted to estimate the drug release, cytotoxic profile, in-vitro blood-brain barrier (BBB) permeability, pharmacokinetic parameter and the concentration of VPA and VANE in blood and brain.

    KEY FINDINGS: Physical characterisation confirmed that VANE was suitable for parenteral administration. Formulating VPA into nanoemulsion significantly reduced the cytotoxicity of VPA. In-vitro drug permeation suggested that VANEs crossed the BBB as freely as VPA. Pharmacokinetic parameters of VANE-treated rats in plasma and brain showed F3 VANE had a remarkable improvement in AUC, prolongation of half-life and reduction in clearance compared to VPA. Given the same extent of in-vitro BBB permeation of VPA and VANE, the higher bioavailability of VANE in brain was believed to have due to higher concentration of VANE in blood. The brain bioavailability of VPA was improved by prolonging the half-life of VPA by encapsulating it within the nanoemulsion-T80.

    CONCLUSIONS: Nanoemulsion containing VPA has alleviated the cytotoxic effect of VPA and improved the plasma and brain bioavailability for parenteral delivery of VPA.

    Matched MeSH terms: Osmolar Concentration
  20. Fulltext Optimization of Processing Parameters of Nanoemulsion Containing Aripiprazole Using Response Surface Methodology
    Samiun WS, Ashari SE, Salim N, Ahmad S
    Int J Nanomedicine, 2020;15:1585-1594.
    PMID: 32210553 DOI: 10.2147/IJN.S198914
    BACKGROUND: Aripiprazole, which is a quinolinone derivative, has been widely used to treat schizophrenia, major depressive disorder, and bipolar disorder.

    PURPOSE: A Central Composite Rotatable Design (CCRD) of Response Surface Methodology (RSM) was used purposely to optimize process parameters conditions for formulating nanoemulsion containing aripiprazole using high emulsification methods.

    METHODS: This design is used to investigate the influences of four independent variables (overhead stirring time (A), shear rate (B), shear time (C), and the cycle of high-pressure homogenizer (D)) on the response variable namely, a droplet size (Y) of nanoemulsion containing aripiprazole.

    RESULTS: The optimum conditions suggested by the predicted model were: 120 min of overhead stirring time, 15 min of high shear homogenizer time, 4400 rpm of high shear homogenizer rate and 11 cycles of high-pressure homogenizer, giving a desirable droplet size of nanoemulsion containing aripiprazole of 64.52 nm for experimental value and 62.59 nm for predicted value. The analysis of variance (ANOVA) showed the quadratic polynomial fitted the experimental values with F-value (9.53), a low p-value (0.0003) and a non-significant lack of-fit. It proved that the models were adequate to predict the relevance response. The optimized formulation with a viscosity value of 3.72 mPa.s and pH value of 7.4 showed good osmolality value (297 mOsm/kg) and remained stable for three months in three different temperatures (4°C, 25°C, and 45°C).

    CONCLUSION: This proven that response surface methodology is an efficient tool to produce desirable droplet size of nanoemulsion containing aripiprazole for parenteral delivery application.

    Matched MeSH terms: Osmolar Concentration
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