Displaying publications 101 - 120 of 185 in total

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  1. Differentiation of patented crystalline glucosamine sulfate from other glucosamine preparations will optimize osteoarthritis treatment
    Saengnipanthkul S, Waikakul S, Rojanasthien S, Totemchokchyakarn K, Srinkapaibulaya A, Cheh Chin T, et al.
    Int J Rheum Dis, 2019 Mar;22(3):376-385.
    PMID: 28332780 DOI: 10.1111/1756-185X.13068
    Symptomatic slow-acting drugs for osteoarthritis (SYSADOAs) are recommended for the medium- to long-term management of knee osteoarthritis (OA) due to their abilities to control pain, improve function and delay joint structural changes. Among SYSADOAs, evidence is greatest for the patented crystalline glucosamine sulfate (pCGS) formulation (Mylan). Glucosamine is widely available as glucosamine sulfate (GS) and glucosamine hydrochloride (GH) preparations that vary substantially in molecular form, pharmaceutical formulation and dose regimen. Only pCGS is given as a highly bioavailable once-daily dose (1500 mg), which consistently delivers the plasma levels of around 10 μmol/L required to inhibit interleukin-1-induced expression of genes involved in the pathophysiology of joint inflammation and tissue destruction. Careful consideration of the evidence base reveals that only pCGS reliably provides a moderate effect size on pain that is higher than paracetamol and equivalent to non-steroidal anti-inflammatory drugs (NSAIDs), while non-crystalline GS and GH fail to reach statistical significance for pain reduction. Chronic administration of pCGS has disease-modifying effects, with a reduction in need for total joint replacement lasting for 5 years after treatment cessation. Pharmacoeconomic studies of pCGS demonstrate long-term reduction in additional pain analgesia and NSAIDs, with a 50% reduction in costs of other OA medication and healthcare consultations. Consequently, pCGS is the logical choice, with demonstrated medium-term control of pain and lasting impact on disease progression. Physician and patient education on the differentiation of pCGS from other glucosamine formulations will help to improve treatment selection, increase treatment adherence, and optimize clinical benefit in OA.
    Matched MeSH terms: Crystallization
  2. Fulltext Investigation of struvite crystals formed in palm oil mill effluent anaerobic digester
    Ngatiman M, Jami MS, Abu Bakar MR, Subramaniam V, Loh SK
    Heliyon, 2021 Jan;7(1):e05931.
    PMID: 33490684 DOI: 10.1016/j.heliyon.2021.e05931
    The formation of struvite crystals or magnesium ammonium phosphate (MgNH4PO4) in palm oil mill effluent (POME) occurs as early as in the secondary stage of POME treatment system. Its growth continues in the subsequent tertiary treatment which reduces piping diameter, thus affecting POME treatment efficiency. Hypothesis. The beneficial use of the crystal is the motivation. This occurrence is rarely reported in scientific articles despite being a common problem faced by palm oil millers. The aim of this study is to characterize struvite crystals found in an anaerobic digester of a POME treatment facility in terms of their physical and chemical aspects. The compositions, morphology and properties of these crystals were determined via energy dispersive spectroscopy (EDS), elemental analysis, scanning electron microscopy (SEM) and x-ray diffraction (XRD). Solubility tests were carried out to establish solubility curve for struvite from POME. Finally, crystal growth experiment was done applying reaction crystallization method to demonstrate struvite precipitation from POME. Results showed that high phosphorous (P) (24.85 wt%) and magnesium (Mg) (21.33 wt%) content was found in the struvite sample. Elemental analysis detected carbon (C), hydrogen (H), nitrogen (N) and sulfur (S) below 4 wt%. The crystals analysed by XRD in this study were confirmed as struvite with 94.8% struvite mineral detected from its total volume. Having an orthorhombic crystal system, struvite crystals from POME recorded an average density of 1.701 g cm-3. Solubility curve of struvite from POME was established with maximum solubility of 275.6 mg L-1 at pH 3 and temperature 40 °C. Minimum solubility of 123.6 mg L-1 was recorded at pH 7 and temperature 25 °C. Crystal growth experiment utilizing POME as the source medium managed to achieve 67% reduction in phosphorous content. This study concluded that there is a potential of harnessing valuable nutrients from POME in the form of struvite. Struvite precipitation technology can be adapted in the management of POME in order to achieve maximum utilization of the nutrients that are still abundant in POME. At the same time maximization of nutrient extractions from POME will also reduce pollutants loading in the final discharge.
    Matched MeSH terms: Crystallization
  3. Crystallization and structure elucidation of GDSL esterase of Photobacterium sp. J15
    Mazlan SNHS, Ali MSM, Rahman RNZRA, Sabri S, Jonet MA, Leow TC
    Int J Biol Macromol, 2018 Nov;119:1188-1194.
    PMID: 30102982 DOI: 10.1016/j.ijbiomac.2018.08.022
    GDSL esterase J15 (EstJ15) is a member of Family II of lipolytic enzyme. The enzyme was further classified in subgroup SGNH hydrolase due to the presence of highly conserve motif, Ser-Gly-Asn-His in four conserved blocks I, II, III, and V, respectively. X-ray quality crystal of EstJ15 was obtained from optimized formulation containing 0.10 M ammonium sulphate, 0.15 M sodium cacodylate trihydrate pH 6.5, and 20% PEG 8000. The crystal structure of EstJ15 was solved at 1.38 Å with one molecule per asymmetric unit. The structure exhibits α/β hydrolase fold and shared low amino acid sequence identity of 23% with the passenger domain of the autotransporter EstA of Pseudomonas aeruginosa. The active site is located at the centre of the structure, formed a narrow tunnel that hinder long substrates to be catalysed which was proven by the protein-ligand docking analysis. This study facilitates the understanding of high substrate specificity of EstJ15 and provide insights on its catalytic mechanism.
    Matched MeSH terms: Crystallization
  4. Synthesis and characterization of polymeric V2O5/AlO(OH) with nanopores on alumina support
    Ahmad AL, Abd Shukor SR, Leo CP
    J Nanosci Nanotechnol, 2006 Dec;6(12):3910-4.
    PMID: 17256351
    Polymeric vanadium pentoxide gel was formed via the reaction of V2O5 powder with hydrogen peroxide. The polymeric vanadium pentoxide gel was then dispersed in alumina gel. Different vanadium loading composites were coated on alumina support and calcined at 500 degrees C for 1 hr. These composite layers were characterized using TGA, FT-IR, XRD, SEM, and Autosorb. It was found that the lamellar structure of polymerized vanadium pentoxide was retained in the inorganic matrix. Crystalline alumina in gamma phase was formed after calcinations. However, the vanadium-alumina mixed oxides are lack of the well defined PXRD peaks for polycrystalline V2O5. This is possibly because the vanadia species are highly dispersed in the alumina matrix or the vanadia species are dispersed as crystalline which is smaller than 4 nm. In addition, the imbedded polymeric vanadium oxide improved the specific area and average pore diameter of the composite layer.
    Matched MeSH terms: Crystallization/methods*
  5. Mechanical properties of thermoplastic natural rubber (TPNR) reinforced with different types of carbon nanotube
    Tarawneh MA, Sahrim Ahmad, Rozaidi Rasid, Yahya S, Shamsul Bahri A, Ehnoum S, et al.
    Sains Malaysiana, 2011;40:1179-1186.
    The effect of various multi-walled carbon nanotubes (MWNTs) on the tensile properties of thermoplastic natural rubber (TPNR) nanocomposite was investigated. The nanocomposite was prepared using melt blending method. MWNTs were added to improve the mechanical properties of MWNTs/TPNR composites in different compositions of 1, 3, 5, and 7 wt.%. The results showed that the mechanical properties of nanocomposites were affected significantly by the composition and the properties of MWNTs. SEM micrographs confirmed the homogenous dispersion of MWNTs in the TPNR matrix and promoted strong interfacial adhesion between MWNTs and the matrix which was improved mechanical properties significantly.
    Matched MeSH terms: Crystallization
  6. Monitoring Drug Crystallization in Percutaneous Penetration Using Localized Nanothermal Analysis and Photothermal Microspectroscopy
    Goh CF, Moffat JG, Craig DQM, Hadgraft J, Lane ME
    Mol Pharm, 2019 01 07;16(1):359-370.
    PMID: 30525649 DOI: 10.1021/acs.molpharmaceut.8b01027
    Drug crystallization on and in the skin has been reported following application of topical or transdermal formulations. This study explored novel probe-based approaches including localized nanothermal analysis (nano-TA) and photothermal microspectroscopy (PTMS) to investigate and locate drug crystals in the stratum corneum (SC) of porcine skin following application of simple ibuprofen (IBU) formulations. We also conducted in vitro skin permeation studies and tape stripping. The detection of drug crystals in the SC on tape strips was confirmed using localized nano-TA, based on the melting temperature of IBU. The melting of IBU was also evident as indicated by a double transition and confirmed the presence of drug crystals in the SC. The single point scans of PTMS on the tape strips allowed collection of the photothermal FTIR spectra of IBU, confirming the existence of drug crystals in the skin. The combined methods also indicated that drug crystallized in the SC at a depth of ∼4-7 μm. Future studies will examine the potential of these techniques to probe crystallization of other commonly used actives in topical and transdermal formulations.
    Matched MeSH terms: Crystallization/methods*
  7. Profiling of drug crystallization in the skin
    Goh CF, Boyd BJ, Craig DQM, Lane ME
    Expert Opin Drug Deliv, 2020 09;17(9):1321-1334.
    PMID: 32634033 DOI: 10.1080/17425247.2020.1792440
    BACKGROUND: Drug crystallization following application of transdermal and topical formulations may potentially compromise the delivery of drugs to the skin. This phenomenon was found to be limited to the superficial layers of the stratum corneum (~7 µm) in our recent reports and tape stripping of the skin samples was necessary. It remains a significant challenge to profile drug crystallization in situ without damaging the skin samples.

    METHODS: This work reports the application of an X-ray microbeam via synchrotron SAXS/WAXS analysis to monitor drug crystallization in the skin, especially in the deeper skin layers. Confocal Raman spectroscopy (CRS) was employed to examine drug distribution in the skin to complement the detection of drug crystallization using SAXS/WAXS analysis.

    RESULTS: Following application of saturated drug solutions (ibuprofen, diclofenac acid, and salts), CRS depth profiles confirmed that the drugs generally were delivered to a depth of ~15 - 20 µm in the skin. This was compared with the WAXS profiles that measured drug crystal diffraction at a depth of up to ~25 µm of the skin.

    CONCLUSION: This study demonstrates the potential of synchrotron SAXS/WAXS analysis for profiling of drug crystallization in situ in the deeper skin layers without pre-treatment for the skin samples. [Figure: see text].

    Matched MeSH terms: Crystallization
  8. The application of ATR-FTIR spectroscopy and multivariate data analysis to study drug crystallisation in the stratum corneum
    Goh CF, Craig DQ, Hadgraft J, Lane ME
    Eur J Pharm Biopharm, 2017 Feb;111:16-25.
    PMID: 27845181 DOI: 10.1016/j.ejpb.2016.10.025
    Drug permeation through the intercellular lipids, which pack around and between corneocytes, may be enhanced by increasing the thermodynamic activity of the active in a formulation. However, this may also result in unwanted drug crystallisation on and in the skin. In this work, we explore the combination of ATR-FTIR spectroscopy and multivariate data analysis to study drug crystallisation in the skin. Ex vivo permeation studies of saturated solutions of diclofenac sodium (DF Na) in two vehicles, propylene glycol (PG) and dimethyl sulphoxide (DMSO), were carried out in porcine ear skin. Tape stripping and ATR-FTIR spectroscopy were conducted simultaneously to collect spectral data as a function of skin depth. Multivariate data analysis was applied to visualise and categorise the spectral data in the region of interest (1700-1500cm(-1)) containing the carboxylate (COO(-)) asymmetric stretching vibrations of DF Na. Spectral data showed the redshifts of the COO(-) asymmetric stretching vibrations for DF Na in the solution compared with solid drug. Similar shifts were evident following application of saturated solutions of DF Na to porcine skin samples. Multivariate data analysis categorised the spectral data based on the spectral differences and drug crystallisation was found to be confined to the upper layers of the skin. This proof-of-concept study highlights the utility of ATR-FTIR spectroscopy in combination with multivariate data analysis as a simple and rapid approach in the investigation of drug deposition in the skin. The approach described here will be extended to the study of other actives for topical application to the skin.
    Matched MeSH terms: Crystallization
  9. Physicochemical properties and crystallisation behaviour of bakery shortening produced from stearin fraction of palm-based diacyglycerol blended with various vegetable oils
    Latip RA, Lee YY, Tang TK, Phuah ET, Tan CP, Lai OM
    Food Chem, 2013 Dec 15;141(4):3938-46.
    PMID: 23993569 DOI: 10.1016/j.foodchem.2013.05.114
    The stearin fraction of palm-based diacylglycerol (PDAGS) was produced from dry fractionation of palm-based diacylglycerol (PDAG). Bakery shortening blends were produced by mixing PDAGS with either palm mid fraction, PMF (PDAGS/PMF), palm olein, POL(PDAGS/POL) or sunflower oil, SFO (PDAGS/SFO) at PDAGS molar fraction of XPDAGS=0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%. The physicochemical results obtained indicated that C16:0 and C18:1 were the dominant fatty acids for PDAGS/PMF and PDAGS/POL, while C18:1 and C18:2 were dominant in the PDAGS/SFO mixtures. SMP and SFC of the PDAGS were reduced with the addition of PMF, POL and SFO. Binary mixtures of PDAGS/PMF had better structural compatibility and full miscibility with each other. PDAGS/PMF and PDAGS/SFO crystallised in β'+β polymorphs in the presence of 0.4-0.5% PDAGS while PDAGS/POL resulted in β polymorphs crystal. The results gave indication that PDAGS: PMF at 50%:50% and 60%:40% (w/w) were the most suitable fat blend to be used as bakery shortening.
    Matched MeSH terms: Crystallization
  10. Fulltext Palm-based diacylglycerol fat dry fractionation: effect of crystallisation temperature, cooling rate and agitation speed on physical and chemical properties of fractions
    Ab Latip R, Lee YY, Tang TK, Phuah ET, Lee CM, Tan CP, et al.
    PeerJ, 2013;1:e72.
    PMID: 23682348 DOI: 10.7717/peerj.72
    Fractionation which separates the olein (liquid) and stearin (solid) fractions of oil is used to modify the physicochemical properties of fats in order to extend its applications. Studies showed that the properties of fractionated end products can be affected by fractionation processing conditions. In the present study, dry fractionation of palm-based diacylglycerol (PDAG) was performed at different: cooling rates (0.05, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0°C/min), end-crystallisation temperatures (30, 35, 40, 45 and 50°C) and agitation speeds (30, 50, 70, 90 and 110 rpm) to determine the effect of these parameters on the properties and yield of the solid and liquid portions. To determine the physicochemical properties of olein and stearin fraction: Iodine value (IV), fatty acid composition (FAC), acylglycerol composition, slip melting point (SMP), solid fat content (SFC), thermal behaviour tests were carried out. Fractionation of PDAG fat changes the chemical composition of liquid and solid fractions. In terms of FAC, the major fatty acid in olein and stearin fractions were oleic (C18:1) and palmitic (C16:0) respectively. Acylglycerol composition showed that olein and stearin fractions is concentrated with TAG and DAG respectively. Crystallization temperature, cooling rate and agitation speed does not affect the IV, SFC, melting and cooling properties of the stearin fraction. The stearin fraction was only affected by cooling rate which changes its SMP. On the other hand, olein fraction was affected by crystallization temperature and cooling rate but not agitation speed which caused changes in IV, SMP, SFC, melting and crystallization behavior. Increase in both the crystallization temperature and cooling rate caused a reduction of IV, increment of the SFC, SMP, melting and crystallization behaviour of olein fraction and vice versa. The fractionated stearin part melted above 65°C while the olein melted at 40°C. SMP in olein fraction also reduced to a range of 26 to 44°C while SMP of stearin fractions increased to (60-62°C) compared to PDAG.
    Matched MeSH terms: Crystallization
  11. Physicochemical, textural and viscoelastic properties of palm diacylglycerol bakery shortening during storage
    Cheong LZ, Tan CP, Long K, Affandi Yusoff MS, Lai OM
    J Sci Food Agric, 2010 Oct;90(13):2310-7.
    PMID: 20661900 DOI: 10.1002/jsfa.4088
    Diacylglycerol (DAG), which has health-enhancing properties, is sometimes added to bakery shortening to produce baked products with enhanced physical functionality. Nevertheless, the quantity present is often too little to exert any positive healthful effects. This research aimed to produce bakery shortenings containing significant amounts of palm diacyglycerol (PDG). Physicochemical, textural and viscoelastic properties of the PDG bakery shortenings during 3 months storage were evaluated and compared with those of commercial bakery shortening (CS).
    Matched MeSH terms: Crystallization
  12. Fulltext The effect of fluorosis on human teeth under light microscopy: A cross-sectional study
    Ramesh M, Narasimhan M, Krishnan R, Aruna RM, Kuruvilla S
    J Oral Maxillofac Pathol, 2017 Sep-Dec;21(3):345-350.
    PMID: 29391706 DOI: 10.4103/jomfp.JOMFP_247_16
    Background: Fluoride is needed for the normal development of bone and teeth; in high levels, it affects developing teeth and bone. Dental fluorosis (DF) is caused by ingestion of excess fluoride mainly through drinking water.

    Aim: The present study aims to observe and understand the histological changes of fluorosed teeth under light microscope (LM).

    Materials and Methods: Teeth which were indicated for extractions for orthodontic or periodontal problems were selected. Thirty extracted teeth were selected with varying degrees of DF based on modified Dean's fluorosis index. Ground sections of these teeth were prepared and the sections were studied under binocular LM. Photomicrographs were taken under high power objective using 15 megapixels Nikon camera.

    Results and Conclusion: Qualitative histologic changes in different grades of fluorosed teeth were evaluated in enamel, dentin, cementum and between their junctions. Fluoride interacts with enamel in both mineral phases and organic macromolecules by strong ionic and hydrogen bonds resulting in incomplete crystal growth at prism peripheries. This presents as hypomineralization of enamel and dentin, increased interglobular dentin, increased secondary curvatures and changes in cementum such as diffuse cementodentinal junction and increased thickness of Tomes' granular layer. Changes in the structure of the teeth with Dean's index below 2 and teeth with Dean's index of 2 and above were compared using Chi-square test. P value was found to be highly significant being 0.00047. Many of the features of dental fluorosis seen in the present study under light microscope are comparable to those results studied under specialized microscopes.
    Matched MeSH terms: Crystallization
  13. Mechanical, thermal and chemical resistance of epoxidized natural rubber toughened polylactic acid blends
    Mat Uzir Wahi, Azman Hassan, Akos Noel Ibrahim, Nurhayati Ahmad Zawawi, Kunasegeran K
    Sains Malaysiana, 2015;44:1615-1623.
    Polylactic acid (PLA)/Epoxidized natural rubber (ENR-50) blends were prepared by melt extrusion followed by injection
    molding to fabricate the test samples. The effect of ENR-50 loadings on the morphological, mechanical, chemical
    resistance and water absorption properties of the blends were studied using standard methods. The toughness of the
    blend improved with ENR loading up to 20 wt. % but flexural and tensile strength decreased. The balanced mechanical
    properties were obtained at 20 wt. % ENR-50 loading. SEM showed good distribution and increased ENR particle size
    as ENR content increased from 10 to 30 wt. %. The differential scanning calorimeter (DSC) showed a steady drop in
    crystallization temperature (Tc
    ) as ENR content increases while the glass transition temperature (Tg
    ) remained unchanged.
    Water absorption was observed to increase with ENR loadings. Increase in ENR content was also observed to reduce the
    chemical resistance of the blends.
    Matched MeSH terms: Crystallization
  14. Molecular Dynamics and Physical Stability of Pharmaceutical Co-amorphous Systems: Correlation Between Structural Relaxation Times Measured by Kohlrausch-Williams-Watts With the Width of the Glass Transition Temperature (ΔTg) and the Onset of Crystallization
    Chieng N, Teo X, Cheah MH, Choo ML, Chung J, Hew TK, et al.
    J Pharm Sci, 2019 12;108(12):3848-3858.
    PMID: 31542436 DOI: 10.1016/j.xphs.2019.09.013
    The study aims to characterize the structural relaxation times of quench-cooled co-amorphous systems using Kohlrausch-Williams-Watts (KWW) and to correlate the relaxation data with the onset of crystallization. Comparison was also made between the relaxation times obtained by KWW and the width of glass transition temperature (ΔTg) methods (simple and quick). Differential scanning calorimetry, Fourier-transformed infrared spectroscopy, and polarized light microscopy were used to characterize the systems. Results showed that co-amorphous systems yielded a single Tg and ΔCp, suggesting the binary mixtures exist as a single amorphous phase. A narrow step change at Tg indicates the systems were fragile glasses. In co-amorphous nap-indo and para-indo, experimental Tgs were in good agreement with the predicted Tg. However, the Tg of co-amorphous nap-cim and indo-cim were 20°C higher than the predicted Tg, possibly due to stronger molecular interactions. Structural relaxation times below the experimental Tg were successfully characterized using the KWW and ΔTg methods. The comparison plot showed that KWW data are directly proportional to the ½ power of ΔTg data, after adjusting for a small offset. A moderate positive correlation was observed between the onset of crystallization and the KWW data. Structural relaxation times may be useful predictor of physical stability of co-amorphous systems.
    Matched MeSH terms: Crystallization/methods
  15. Fulltext Study of growth in Bi2Sr2CaCu2Oy single crystals
    Razak Mohd Ali Lee, Khairul Anwar Mohamad, Katsuyoshi, Hamasaki
    Journal of Nuclear and Related Technologies, 2007;2007(1):195-198.
    MyJurnal
    We put attention on Intrinsic Josephson Junction (IJJ) to study the fundamental physic for device applications. Convenient self-flux method was used to grow BSCCO single crystals. We investigated the lid effect to examine the single crystal growth of high TC (Critical Temperature). We found that for the crystal growth with no lid, two stage transitions of TC ≅ 61 K and 77 K were observed. While for the crystal growth with lid, the BSCCO has TC ≅ 80K, ΔTC = 10K and approximately average size5x2mm 2 . When we increased weight of lid, the single crystal have increased to TC =80K, ΔTC = 4K and the typical size was ≅7x3mm 2 . TC and the crystal growth show a tendency to increase by the effect of the lid. From observed quasi-particle characteristics, c-axis direction changed from semiconductor to intrinsic Josephson characteristic with decreasing temperature.
    Matched MeSH terms: Crystallization
  16. Fulltext Enhancement of mechanical properties of blended polyethylene radiation capsules for the triga mark II research reactor
    Fatema Anuar, Mohammed Iqbal Shueb, Ruzitah Mohd Salleh, Nazaratul Ashifa Abdullah Salim, Julia Abdul Karim
    Jurnal Sains Nuklear Malaysia, 2012;24(2):1-13.
    MyJurnal
    Mechanical properties of blended polyethylene (PE) containing the antioxidant Irganox 1010 and the UV-absorber Tinuvin 326 were studied for future use as radiation capsule material for the TRIGA Mark II research reactor. High density and low density polyethylene were blended with the additives and tested for elongation at break, impact strength and gel content, before and after irradiation inside the nuclear reactor. Characterization via FTIR as well as determination of crystallization and melt transition temperatures through DSC were also conducted. It was found that the addition of the antioxidant at different amounts (from 0 to 4 phr) had various effects on the properties of the blended PE, with 0 phr being the amount at which there was the biggest increase in elongation at break and impact strength, post-irradiation.
    Matched MeSH terms: Crystallization
  17. Stimuli-responsive bacterial cellulose-g-poly(acrylic acid-co-acrylamide) hydrogels for oral controlled release drug delivery
    Mohd Amin MC, Ahmad N, Pandey M, Jue Xin C
    Drug Dev Ind Pharm, 2014 Oct;40(10):1340-9.
    PMID: 23875787 DOI: 10.3109/03639045.2013.819882
    This study evaluated the potential of stimuli-responsive bacterial cellulose-g-poly(acrylic acid-co-acrylamide) hydrogels as oral controlled-release drug delivery carriers. Hydrogels were synthesized by graft copolymerization of the monomers onto bacterial cellulose (BC) fibers by using a microwave irradiation technique. The hydrogels were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). FT-IR spectroscopy confirmed the grafting. XRD showed that the crystallinity of BC was reduced by grafting, whereas an increase in the thermal stability profile was observed in TGA. SEM showed that the hydrogels exhibited a highly porous morphology, which is suitable for drug loading. The hydrogels demonstrated a pH-responsive swelling behavior, with decreased swelling in acidic media, which increased with increase in pH of the media, reaching maximum swelling at pH 7. The release profile of the hydrogels was investigated in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF). The hydrogels showed lesser release in SGF than in SIF, suggesting that hydrogels may be suitable drug carriers for oral controlled release of drug delivery in the lower gastrointestinal tract.
    Matched MeSH terms: Crystallization
  18. The inophyllums, novel inhibitors of HIV-1 reverse transcriptase isolated from the Malaysian tree, Calophyllum inophyllum Linn
    Patil AD, Freyer AJ, Eggleston DS, Haltiwanger RC, Bean MF, Taylor PB, et al.
    J Med Chem, 1993 Dec 24;36(26):4131-8.
    PMID: 7506311
    As part of a search for novel inhibitors of HIV-1 reverse transcriptase, the acetone extract of the giant African snail, Achatina fulica, was shown to be active. Fractionation of the extract yielded inophyllums A, B, C, and E and calophyllolide (1a, 2a, 3a, 3b, and 6), previously isolated from Calophyllum inophyllum Linn., a known source of nutrition for A. fulica. From a methanol/methylene chloride extract of C. inophyllum, the same natural products in considerably greater yield were isolated in addition to a novel enantiomer of soulattrolide (4), inophyllum P (2b), and two other novel compounds, inophyllums G-1 (7) and G-2 (8). The absolute stereochemistry of inophyllum A (1a) was determined to be 10(R), 11(S), 12(S) from a single-crystal X-ray analysis of its 4-bromobenzoate derivative, and the relative stereochemistries of the other inophyllums isolated from C. inophyllum were established by a comparison of their 1H NMR NOE values and coupling constants to those of inophyllum A (1a). Inophyllums B and P (2a and 2b) inhibited HIV reverse transcriptase with IC50 values of 38 and 130 nM, respectively, and both were active against HIV-1 in cell culture (IC50 of 1.4 and 1.6 microM). Closely related inophyllums A, C, D, and E, including calophyllic acids, were significantly less active or totally inactive, indicating certain structural requirements in the chromanol ring. Altogether, 11 compounds of the inophyllum class were isolated from C. inophyllum and are described together with the SAR of these novel anti-HIV compounds.
    Matched MeSH terms: Crystallization
  19. Hydroxyapatite nanoparticles: electrospinning and calcination of hydroxyapatite/polyvinyl butyral nanofibers and growth kinetics
    Zakaria SM, Sharif Zein SH, Othman MR, Jansen JA
    J Biomed Mater Res A, 2013 Jul;101(7):1977-85.
    PMID: 23225849 DOI: 10.1002/jbm.a.34506
    Electrospinning of hydroxyapatite (HA)/polyvinyl butyral solution resulted in the formation of fibers with average diameter of 937-1440 nm. These fibers were converted into HA nanoparticles with size <100 nm after undergoing calcination treatment at 600°C. The diameter of the fiber was found to be influenced by applied voltage and spinning distance. The injection flowrate did not affect the diameter significantly. The electrospinning method successfully reduced the commercial HA particle size in the range of 400-1100 nm into <100 nm. The dispersion of the finally calcined HA nanoparticles was improved significantly after anionic sodium dodecyl sulfate surfactant was introduced. The experimental data of HA growth kinetics were subjected to the integral method of analysis, and the rate law of the reaction was found to follow the first order reaction.
    Matched MeSH terms: Crystallization
  20. Multiple crystallization as a potential strategy for efficient recovery of succinic acid following fermentation with immobilized cells
    Luthfi AAI, Tan JP, Isa NFAM, Bukhari NA, Shah SSM, Mahmod SS, et al.
    Bioprocess Biosyst Eng, 2020 Jul;43(7):1153-1169.
    PMID: 32095989 DOI: 10.1007/s00449-020-02311-x
    This study aimed to enhance the crystallizability of bio-based succinic acid for its efficient recovery while maintaining the end product at the highest purity. Immobilization of Actinobacillus succinogenes was initially evaluated based on three different carriers: volcanic glass, clay pebbles, and silica particles. The adsorption capacity of metabolites with a low concentration (10 g/L) and a high concentration (40 g/L) was investigated. It was demonstrated that clay pebbles adsorbed the least succinic acid (
    Matched MeSH terms: Crystallization
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