18 research outputs found
Nanoformulated Delivery Systems of Essential Nutraceuticals and Their Applications
Malnutrition and poor diet constitute the number one driver of the global burden of disease. Undernutrition is responsible for up to 50% of all deaths in children under the age of 5. In South Africa, 25% of the countryâs children suffer from undernutrition. This increases the risk of child mortality as well as contracting infectious diseases. It also affects the physical and intellectual development of the children. The greatest drawback in malnutrition is the deficiency of essential nutraceuticals involved in important biological functions. Innovative technologies such as nanoformulated products are needed for food and agriculture in order to enhance the childrenâs health. The evaluation and application of various nanoformulated delivery systems will be explored for improving the stability and bioavailability of essential nutraceuticals for consumers
Nanoencapsulation of water-soluble drug, lamivudine, using a double emulsion spray-drying technique for improving HIV treatment
This research article published by Springer Nature Switzerland AG., 2013Current treatments available for human immunodeficiency virus, namely antiretrovirals, do not
completely eradicate the virus from the body, leading to life-time commitment. Many
antiretrovirals suffer drawbacks from toxicity and unpleasant side effects, causing patience noncompliance.
To minimize challenges associated with the antiretrovirals, biodegradable
nanoparticles used as drug delivery systems hold tremendous potential to enhance patience
compliance. The main objective of this work was to load lamivudine (LAM) into poly(epsiloncaprolactone)
(PCL)
nanoparticles.
LAM
is
a hydrophilic
drug
with low
plasma
half-life
of
5â7
h
and
several
unpleasant
side
effects.
LAM
was
nanoencapsulated
into
PCL
polymer
via
the
double
emulsion
spray-drying method. Formulation parameters such as the effect of solvent, excipient
and drug concentration were optimized for the synthesis of the nanoparticles. Spherical
nanoparticles with an average size of 215 ± 3 nm and polydispersity index (PDI) of 0.227 ± 0.01
were obtained, when ethyl acetate and lactose were used in the preparation. However,
dichloromethane presented sizes larger than 454 ± 11 nm with PDI of more than 0.4 ± 0.05,
irrespective of whether lactose or trehalose was used in the preparation. Some of the nanoparticles
prepared with trehalose resulted in crystal formation. UV spectroscopy showed encapsulation
efficiency ranging from 68 ± 4 to 78 ± 4 % for LAM depending on the starting drug concentration.
Fourier transform infrared spectroscopy and X-ray diffraction confirmed the possibility of
preparing amorphous PCL nanoparticles containing LAM. Drug release extended for 4 days in pH
1.3, pH 4.5 and pH 6.8. These results indicated that LAM-loaded PCL nanoparticles show promise
for controlled delivery
Synergistic broad-spectrum antibacterial activity of Hypoxis hemerocallidea-derived silver nanoparticles and streptomycin against respiratory pathobionts
Respiratory tract infections arise due to the introduction of microbes into the airway, disrupting the normal, healthy, complex interdependent microbiome. The selective disruption of this community can be either beneficial or dangerous. Nanoparticles are a potential tool for modifying this population. Coated silver nanoparticles (AgNPs) were synthesized using ethanolic extracts of Hypoxis hemerocallidea (EEHH), a Southern African plant used extensively in traditional medicine and the source of many bioactive secondary metabolites. The room temperature reaction between silver nitrate and EEHH forms largely spherical AgNPs with an average diameter of 6â20 nm. These nanoparticles show similar levels of antibacterial activity as the broad-spectrum antibiotic streptomycin against Bacillus cereus, Streptococcus pneumonia, Escherichia coli, Pseudomonas aeuroginosa, and Moraxella catarrhalis. However, the AgNPs synergistically increase the antibacterial activity of streptomycin when they are applied in combination (30â52%). AgNPs are reiterated to be promising dual-function antibiotics, synergistically enhancing activity while also acting as delivery agents for small molecules
Design and formulation of nano-sized spray dried efavirenz-part I: influence of formulation parameters
This research article published by Springer Nature Switzerland AG.,2012Efavirenz (EFV) is one of the first-line antiretroviral drugs recommended by the World Health Organisation for treating HIV. It is a hydrophobic drug that suffers from low aqueous solubility (4 Όg/mL), which leads to a limited oral absorption and low bioavailability. In order to improve its oral bioavailability, nano-sized polymeric delivery systems are suggested. Spray dried polycaprolactone-efavirenz (PCL-EFV) nanoparticles were prepared by the double emulsion method. The Taguchi method, a statistical design with an L8 orthogonal array, was implemented to optimise the formulation parameters of PCL-EFV nanoparticles. The types of sugar (lactose or trehalose), surfactant concentration and solvent (dichloromethane and ethyl acetate) were chosen as significant parameters affecting the particle size and polydispersity index (PDI). Small nanoparticles with an average particle size of less than 254 ± 0.95 nm in the case of ethyl acetate as organic solvent were obtained as compared to more than 360 ± 19.96 nm for dichloromethane. In this study, the type of solvent and sugar were the most influencing parameters of the particle size and PDI. Taguchi method proved to be a quick, valuable tool in optimising the particle size and PDI of PCL-EFV nanoparticles. The optimised experimental values for the nanoparticle size and PDI were 217 ± 2.48 nm and 0.093 ± 0.02
Determination of radical scavenging activities of some pyrimidine derivatives
Purpose: To synthesize some pyrimidine derivatives and investigate their radical scavenging activities.
Methods: A series of newly pyranopyrimidines derivatives and dithiopyridopyrimidinediones were synthesized by condensation of barbituric acid, malononitrile and different substituted benzaldehydes reacted with 1,4-Diazabicyclo[2.2.2] octane (DABCO) as a base. Compounds P1-7 (series 1), S1-11 (series 2) Scheme 1 and 6-amino-2-thiouracil with aromatic aldehydes in glacial acetic acid under reflux J1-13 (series 3) Scheme 2. 1H & 13C NMR, CHN, GC-MS and IR were used to characterize the compounds and were also screened for radical scavenging activity using 2,2-diphenyl- 1-picrylhydrazyl (DPPH) radical scavenging activity (IC50 = 50 ÎŒg/ml).
Results: The potency of radical scavenging activity was ranked as series 1 > series 3 > series 2. Compounds P3, J4, S10, P5, P7 with inhibitory concentration at 50 % level (IC50) of 12, 40, 48, 50, and 54 ÎŒg/ml, respectively, showed radical scavenging activity equal or more potent than the standard antioxidant, ascorbic acid (IC50 = 50 ÎŒg/ml).
Conclusion: Series of newly pyranopyrimidines and dithiopyridopyrimidinediones derivatives have been successfully synthesized, and they demonstrate good radical scavenging activity.
Keywords: Pyranopyrimidine, Dipyrimidines, Anti-oxidant, DPPH, Ascorbic acid, Radical scavengin
Nanoengineered Polysaccharide-Based Adsorbents as Green Alternatives for Dye Removal from Wastewater
Water represents one of the essential resources on earth, and all living organisms rely on it for survival. However, freshwater systems are directly under serious threat by human activities. A recent World Health Organization report has estimated that 2 billion people use contaminated water sources. The major organic contaminants in water bodies include organic dyes. These are directly related to the spread of diseases owing to their allergenic, mutagenic, and carcinogenic characteristics. Dyes occur in the environment through untreated industrial effluents. Also, the advancement in human civilisation cannot be considered without the development of modern industries. However, an attempt to limit the resulting impacts of coloured effluents on global freshwater quality has become the focus of recent research. For this reason, the use of efficient, simple, and low-cost methods for the treatment of dyes-containing industrial wastewater could serve as a useful tool. An effort to meet the demand for âgreen chemistryâ and sustainable development has led to several investigations on polysaccharide-based adsorbents. This chapter exposes a critical discussion on the literature concerning the biopolymeric xanthan gum and kappa-carrageenan polysaccharides as adsorbents for dye removal in an aqueous medium. Functionalisation of these biopolymers through graft copolymerisation and inclusion of inorganic nanoparticles for improved adsorption performance is systematically elaborated
Polyaniline-Based Nanocomposites for Environmental Remediation
With growth in civilisation and industrialisation, there is an increase in the release of toxic heavy metal ions and dyes into water system, which is of public concern. As a result, appropriate treatment methods have to be implemented in order to mitigate and prevent water pollution. The discovery of nanotechnology has led to the development and utilisation of various nanoadsorbent for the removal of pollutants from water. PANI nanostructures and nanocomposites are noble adsorbents that have gained popularity in addressing water pollution issues and have been reported in literature. In this chapter, the main focus is on the synthesis of PANI nanocomposites and nanostructures and their application as efficient adsorbents for water treatment. Detailed discussions on different synthetic routes and characterisation have been dedicated to applications of these materials and are compared for the adsorptive removal of heavy metal ions and dyes from water
Separation of readily biodegradable aminocarboxylate complexes by electrodriven methods
Thesis(PhD)--Stellenbosch University, 2008.ENGLISH ABSTRACT: Aminopolycarboxylic acids (APCAs) are chelating agents widely used to inactivate
various metal ions by complex formation in industrial and household applications.
Ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA)
are the widely used agents. Their use is under scrutiny due to their persistence in the
environment because they cannot readily biodegrade. This led to the introduction of
readily biodegradable agents namely ethylenediaminedisuccinic acid (EDDS) and
iminodisuccinic acid (IDS) as alternatives especially to EDTA. Therefore, there was an
interest to study the separation of EDDS, IDS and other APCAs using a simple, quick and
accurate method.
Capillary electrophoresis was used to determine the separation and speciation of
iminodisuccinic acid with various metal ions at various pH levels. Speciation modelling
was also utilized to compare and validate the presence and distribution of metal-ligand
species. The obtained CE results were compared with speciation profiles and a reasonable
agreement was obtained.
The degradation studies at various time intervals for the metal-ligand (ML) complexes of
DTPA, S,S-EDDS, IDS and R,S-IDS with various metal ions (Cd2+, Cr3+, Cu2+, Fe3+,
Mn2+, Pb2+ and Zn2+) at pH 7 and 9 was evaluated using CE. New peaks were observed in
some ML complexes when the pH was changed from pH 9 to 7. Sharp peaks were seen
for CuL (L = DTPA, S,S-EDDS, IDS and R,S-IDS), FeDTPA and FeEDDS at both pH s.
While small broad peaks were observed for FeIDS, CrL and MnL complexes. CuDTPA
and CuEDDS complexes showed a greater stability over some considerable time as
compared to CuIDS, CuR,S-IDS and other metal complexes at pH 9.
This work also investigated the effect of various cationic electroosmotic flow (EOF)
modifiers and counter anions on the CE separation of EDTA, EDDS and IDS as Cu(II)
complexes. The performance of the modifiers was evaluated in terms of migration times,
resolution and plate numbers. The best results were observed when Tetradecyltrimethylammonium bromide (TTAB) and Cetyltrimethylammonium bromide
(CTAB) was used as modifiers in order to reverse the EOF in the fused silica capillary.
This resulted in short analysis time and better peak shapes. The effect of different
counteranions attached to EOF modifiers on the separation was also shown. It was also
found that the counter anions of EOF modifiers used influences the separation of the
complexes. The EOF modifiers namely Cetyltrimethylammonium chloride (CTAC) and
Tetradecyltrimethylammonium chloride (TTAC) were further utilized for the
determination of EDTA in South African river waters and industrial effluents.
A method for the simultaneous separation of Fe (III) complexed with EDTA, S,S -EDDS
and IDS was developed by CE and high-performance liquid chromatography (HPLC).
The recalcitrant EDTA is used in combination with readily biodegradable analogues like
EDDS and IDS in many commercial products. The methodology performance was
evaluated in terms of linearity, limit of detection (LOD), limit of quantitation (LOQ) and
reproducibility for both CE and HPLC methods. The LOD values obtained from HPLC
were low when compared with CE. The applicability of both methods was demonstrated
for the analysis of cosmetic products such as foam bath and shower cream. The results
obtained by both CE and HPLC were found to be comparable and are in good agreement.AFRIKAANSE OPSOMMING: Aminopolikarboksiel sure (APCAs) is komplekseer middels wat algemeen gebruik word
om verskillende metaal ione te deaktifeer deur kompleks vorming in industriële en
huishoudige toepassings. Etileendiamientetraasynsuur (EDTA) en
dietileentriamienpentaasyn suur (DTPA) is die mees algemene APCA s. Hul gebruik
word deesdae noukerig ondersoek as gevolg van hul volharding in die omgewing. Daar
is n intense soektog na bio-afbreekbare agente soos etieleendiamiendisuksien suur
(EDDS) and iminodisuksien suur (IDS) wat as plaasvervangers kan dien vir nieafbreekbare
EDTA. Daar is dus n behoefte om te kyk na eenvoudige, vinnige en
noukeurige metodes vir die bepaling van EDTA, EDTA , IDS en ander APCA s.
Kapillere elektroforese (CE) was gebruik vir die skeiding en spesiering van
iminodisuksien suur met verskillende metale by verskillende pH s. Spesiasie modellering
was ook gebruik om die teenwoordigheid en verspreiding van metaal- spesies te vergelyk.
Die CE uitslae was met die spesiasie profiele vergelyk en n redelike ooreenkoms was
gevind.
Die degraderings studies as n funksie van tyd was met CE bestudeer vir verskillende
metal-ligand (ML) samestellings van DTPA, S,S-EDDS, IDS en R,S-IDS met
verskillende metal ione (Cd2+, Cr3+, Cu2+, Fe3+, Mn2+, Pb2+ en Zn2+) by pH 7 en 9. Nuwe
pieke was opgemerk in sommige ML samestellings wanneer die pH van pH 9 na 7
verander. Hoë pieke was vir CuL (L = DTPA, S,S-EDDS, IDS and R,S-IDS), FeEDTA
en FeEDDS by alle pH s gevind. Lae, breë pieke was vir FeIDS, CrL en MnL komplekse
gevind. CuDTPA en CuEDDS komplekse het n goeie stabiliteit gewys oor Ć redelike tyd
as dit met CuIDS, CuR,S-IDS en ander metal komplekses by pH 9 vergelyk word.
In hierdie werk was die effek van verskillende kationiese elektro-osmotiese stroom (EOF)
modifiseerders ook ondersoek. Veral die effek wat teen ioone op die CE skeidings het
van EDTA, EDDS en IDS asook Cu(II) komplekse was ondersoek. Die effek van die
modifiseerders was ondersoek en ge-evalueer in terme van migrasie tye, resolusie en plaat getalle. Die beste skeidingskondisies was bereik wanneer
tetradesieltrimetielammonium bromied (TTAB) and setieltrimetielammonium bromied
(CTAB) as modifiseerders gebruik word. Hierdie kondisies het ook aanleiding gegee tot
korter ondersoek tye en beter piekvorme. Die effek van verskillende teen ioone wat aan
die EOF modifiseerders gekoppel was het ook interresante resultate opgelewer. Die EOF
modifiseerders setieltrimetielammonium chloried (CTAC) en
tetradesieltrimetielammonium chloried (TTAC) was ook gebruik vir die bepaling van
EDTA in Suid Afrikaanse rivier waters en industrieel afloop.
Ć Metode vir die gelyktydige skeiding van Fe(III) met EDTA, S,Sâ-EDDS en IDS was
met behulp van CE en hoedruk vloeistof chromatography (HPLC) ontwikkel. Die
metodologie was ondersoek ingevolge lineariteit, limiet van deteksie (LOD), limiet van
kwantifisering (LOQ) en die herhaalbaarheid van CE en die HPLC metodes. Die LOD
waardes verkry vanaf HPLC was swakker vergeleke met die verkry deur CE. Die
toepaslikheid van al die metodes was vir die ontleding van kosmetiese produkte soos bad
skuim en stortbad room getoets. Die uitslae deur CE en HPLC was vergelykbaar en Ć
goeie ooreenkoms was gevind
Sulphate-supplemented NPK nanofertilizer and its effect on maize growth
Sulphate-supplemented nitrogen, phosphorus and potassium (NPKS) fertilizer was nanoformulated through ionic gelation of chitosan (CS) and tripolyphosphate (TPP) at pH value of 5.5 to afford a series of nanofertilizers. The CS-TPP nanoparticles and CS-TPP-NPKS nanofertilizers were engineered using different dose of CS (0.125, 0.25, 0.5 and 1%) and NPKS fertilizer (20, 40 and 60 ppm). These nanoparticles were characterized through particle size distribution, zeta potential, SEM, XRD, FTIR, EDX and ICP-MS. The results revealed CS-TPP-NPKS particles with size range of 220â530 nm, polydispersity index (PDI) value between 0.2â0.5 and positive zeta potential. A preliminary evaluation of these nanoparticles along with inorganic NPK and NPKS fertilizers were conducted under greenhouse condition using maize ( Zea mays L.) as a test crop. Findings from this study showed that inorganic NPKS (20:7:3:0.5) fertilizer, CS-TPP nanoparticles, and formulated NPKS nanofertilizers gave higher maize plants growth increases than NPK fertilizer and control treatments. The tallest plant (37.73 cm) and highest number of leaves (9) were recorded with the CS-TPP-NPKS nanofertilizer treatment obtained using 1% CS/NPKS (40 ppm). On the other hand, application of the nanoformulated derivative with 0.25% CS/NPKS (20 ppm) produced maize plants with superior chlorophyll content with 12.71 chlorophyll index value. A highly varied magnitude of the coefficient of variation in nutrient contents and uptake was recorded among the treatments. These results revealed that the incorporation of sulphur nutrient into NPK fertilizer and its transformation to nanoparticles have the potential characteristics for effective and productive growth of maize and sustainable agricultural activities
In Situ Stabilisation of Silver Nanoparticles at Chitosan-Functionalised Graphene Oxide for Reduction of 2,4-Dinitrophenol in Water
This investigation reports the in situ growth of silver nanoparticles onto covalently bonded graphene oxide-chitosan, which serve as supported nanocatalysts for the NaBH4 reduction of 2,4-dinitrophenol in aqueous systems. Fumaryl chloride reacted with chitosan in an acidic environment to yield a tailored polymeric material. The latter was, in turn, treated with the pre-synthesised graphene oxide sheets under acidic conditions to generate the GO-functionalised membrane (GO-FL-CS). The adsorption of Ag+ from aqueous media by GO-FL-CS yielded a set of membranes that were decorated with silver nanoparticles (Ag NPs@GO-FL-CS) without any reducing agent. Various analytical tools were used to characterise these composites, including Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller surface area analysis, X-ray diffraction, scanning electron microscopy/energy-dispersive X-ray analysis, inductively coupled plasma-mass spectrometry, and transmission electron microscopy. The silver-loaded materials were further used for the remediation of 2,4-dinitrophenol from aqueous solutions under batch operation. The BET analysis revealed that the functionalisation of GO with chitosan and Ag NPs (average size 20â60 nm) resulted in a three-fold increased surface area. The optimised catalyst (Ag mass loading 16.95%) displayed remarkable activity with an apparent pseudo-first-order rate constant of 13.5 Ă 10â3 minâ1. The cyclic voltammetry experiment was conducted to determine the nitro-conversion pathway. The reusability/stability test showed no significant reduction efficiency of this metal-laden composite over six cycles. Findings from the study revealed that Ag NPs@GO-FL-CS could be employed as a low-cost and recyclable catalyst to convert toxic nitroaromatics in wastewater