Arginine–chitosan- and arginine–polyethylene glycol-conjugated superparamagnetic nanoparticles: preparation, cytotoxicity and controlled-release

Iron oxide magnetic nanoparticles (MNPs) can be used in targeted drug delivery systems for localized cancer treatment. MNPs coated with biocompatible polymers are useful for delivering anticancer drugs. Iron oxide MNPs were synthesized via co-precipitation method then coated with either chitosan (CS) or polyethylene glycol (PEG) to form CS–MNPs and PEG–MNPs, respectively. Arginine (Arg) was loaded onto both coated nanoparticles to form Arg–CS–MNP and Arg–PEG–MNP nanocomposites. The X-ray diffraction results for the MNPs and the Arg–CS–MNP and Arg–PEG–MNPs nanocomposites indicated that the iron oxide contained pure magnetite. The amount of CS and PEG bound to the MNPs were estimated via thermogravimetric analysis and confirmed via Fourier transform infrared spectroscopy analysis. Arg loading was estimated using UV–vis measurements, which yielded values of 5.5% and 11% for the Arg–CS–MNP and Arg–PEG–MNP nanocomposites, respectively. The release profile of Arg from the nanocomposites followed a pseudo-second-order kinetic model. The cytotoxic effects of the MNPs, Arg–CS–MNPs, and Arg–PEG–MNPs were evaluated in human cervical carcinoma cells (HeLa), mouse embryonic fibroblast cells (3T3) and breast adenocarcinoma cells (MCF-7). The results indicate that the MNPs, Arg–CS–MNPs, and Arg–PEG–MNPs do not exhibit cytotoxicity toward 3T3 and HeLa cells. However, treatment of the MCF-7 cells with the Arg–CS–MNP and Arg–PEG–MNP nanocomposites reduced the cancer cell viability with IC50 values of 48.6 and 42.6 µg/mL, respectively, whereas the MNPs and free Arg did not affect the viability of the MCF-7 cells

Development of a controlled-release anti-parkinsonian nanodelivery system using levodopa as the active agent.

A new layered organic-inorganic nanocomposite material with an anti-parkinsonian active compound, L-3-(3,4-dihydroxyphenyl) alanine (levodopa), intercalated into the inorganic interlayers of a Zn/Al-layered double hydroxide (LDH) was synthesized using a direct coprecipitation method. The resulting nanocomposite was composed of the organic moiety, levodopa, sandwiched between Zn/Al-LDH inorganic interlayers. The basal spacing of the resulting nano-composite was 10.9 Å. The estimated loading of levodopa in the nanocomposite was approximately 16% (w/w). A Fourier transform infrared study showed that the absorption bands of the nanocomposite were characteristic of both levodopa and Zn/Al-LDH, which further confirmed intercalation, and that the intercalated organic moiety in the nanocomposite was more thermally stable than free levodopa. The resulting nanocomposite showed sustained-release properties, so can be used in a controlled-release formulation. Cytotoxicity analysis using an MTT assay also showed increased cell viability of 3T3 cells exposed to the newly synthesized nanocomposite compared with those exposed to pure levodopa after 72 hours of exposure

Development of antiproliferative nanohybrid compound with controlled release property using ellagic acid as the active agent

An ellagic acid (EA)–zinc layered hydroxide (ZLH) nanohybrid (EAN) was synthesized under a nonaqueous environment using EA and zinc oxide (ZnO) as the precursors. Powder X-ray diffraction showed that the basal spacing of the nanohybrid was 10.4 Å, resulting in the spatial orientation of EA molecules between the interlayers of 22.5° from z-axis with two negative charges at 8,8′ position of the molecules pointed toward the ZLH interlayers. FTIR study showed that the intercalated EA spectral feature is generally similar to that of EA, but with bands slightly shifted. This indicates that some chemical bonding of EA presence between the nanohybrid interlayers was slightly changed, due to the formation of host–guest interaction. The nanohybrid is of mesopores type with 58.8% drug loading and enhanced thermal stability. The release of the drug active, EA from the nanohybrid was found to be sustained and therefore has good potential to be used as a drug controlled-release formulation. In vitro bioassay study showed that the EAN has a mild effect on the hepatocytes cells, similar to its counterpart, free EA

Preparation and controlled-release studies of a protocatechuic acid-magnesium/aluminum-layered double hydroxide nanocomposite.

In the study reported here, magnesium/aluminum (Mg/Al)-layered double hydroxide (LDH) was intercalated with an anticancer drug, protocatechuic acid, using ion-exchange and direct coprecipitation methods, with the resultant products labeled according to the method used to produce them: "PANE" (ie, protocatechuic acid-Mg/Al nanocomposite synthesized using the ion-exchange method) and "PAND" (ie, protocatechuic acid-Mg/Al nanocomposite synthesized using the direct method), respectively. Powder X-ray diffraction and Fourier transform infrared spectroscopy confirmed the intercalation of protocatechuic acid into the inter-galleries of Mg/Al-LDH. The protocatechuic acid between the interlayers of PANE and PAND was found to be a monolayer, with an angle from the z-axis of 8° for PANE and 15° for PAND. Thermogravimetric and differential thermogravimetric analysis results revealed that the thermal stability of protocatechuic acid was markedly enhanced upon intercalation. The loading of protocatechuic acid in PANE and PAND was estimated to be about 24.5% and 27.5% (w/w), respectively. The in vitro release study of protocatechuic acid from PANE and PAND in phosphate-buffered saline at pH 7.4, 5.3, and 4.8 revealed that the nanocomposites had a sustained release property. After 72 hours incubation of PANE and PAND with MCF-7 human breast cancer and HeLa human cervical cancer cell lines, it was found that the nanocomposites had suppressed the growth of these cancer cells, with a half maximal inhibitory concentration of 35.6 μg/mL for PANE and 36.0 μg/mL for PAND for MCF-7 cells, and 19.8 μg/mL for PANE and 30.3 μg/mL for PAND for HeLa cells. No half maximal inhibitory concentration for either nanocomposite was found for 3T3 cells

Controlled release and angiotensin-converting enzyme inhibition properties of an antihypertensive drug based on a perindopril erbumine-layered double hydroxide nanocomposite.

The intercalation of perindopril erbumine into Zn/Al-NO3-layered double hydroxide resulted in the formation of a host-guest type of material. By virtue of the ionexchange properties of layered double hydroxide, perindopril erbumine was released in a sustained manner. Therefore, this intercalated material can be used as a controlled-release formulation. Results: Perindopril was intercalated into the interlayers and formed a well ordered, layered organic-inorganic nanocomposite. The basal spacing of the products was expanded to 21.7 Å and 19.9 Å by the ion-exchange and coprecipitation methods, respectively, in a bilayer and a monolayer arrangement, respectively. The release of perindopril from the nanocomposite synthesized by the coprecipitation method was slower than that of its counterpart synthesized by the ion-exchange method. The rate of release was governed by pseudo-second order kinetics. An in vitro antihypertensive assay showed that the intercalation process results in effectiveness similar to that of the antihypertensive properties of perindopril. Conclusion: Intercalated perindopril showed better thermal stability than its free counterpart. The resulting material showed sustained-release properties and can therefore be used as a controlled-release formulation

The Role Of Strategic Talent Management (STM) To Enhance Jobs Performances In Oil & Gas Companies In The UAE : A Conceptual Framework

Workforce related issues have sustained to fuel the war for talent in Oil & Gas sector, in which the UAE is one of the main players in this industry globally. Most of the local companies are heavily depending on the knowledge and skills of foreign experts for its competitive advantage. In this case, jobs roles localization (Emiratization) has become an imperative and efforts need to be done to lure the local workforce to be part of the local companies. Therefore, there is a need to propose a Strategic Talent Management (STM) so that the local employees can contribute productively to the economic growth of the country. This study aims to address the issues of the shortage of the skilled domestic workforce by proposing a STM practices to enhance job performance among local employees for achieving the competitive advantage of the Oil & Gas companies in the UAE. As the initial stage of the investigation, this paper presents the conceptual framework, highlighting the constructs of the variables to be investigated in this study. Drawn from the analysis of the existing literature, this study is framed by four concepts, which are the STM, job motivation, job retention and job performance. Positioned within a positivist paradigm, eight hypotheses have been formulated in the study. It is expected that the development of the conceptual framework of this study will guide the investigation of the role of strategic talent management that can enhance the job performance of the local employees in the oil and gas companies at the UAE

Hippurate-Zinc layered Hydroxide Nanohybrid and its synergistic effect with Tamoxifen on the HepG2 cell lines.

A new simple preparation method for a hippurate intercalated zinc-layered hydroxide (ZLH) nanohybrid has been established, which does not need an anion-exchange procedure to intercalate the hippurate anion into ZLH interlayers. Methods: The hippuric acid nanohybrid (HAN) was prepared by direct reaction of an aqueous suspension of zinc oxide with a solution of hippuric acid via a one-step method. Results: The basal spacing of the nanohybrid was 21.3 Å, indicating that the hippurate anion was successfully intercalated into the interlayer space of ZLH, and arranged in a monolayer fashion with the carboxylate group pointing toward the ZLH inorganic interlayers. A Fourier transform infrared study confirmed the formation of the nanohybrid, while thermogravimetry and differential thermogravimetry analyses showed that the thermal stability of the nanohybrid was markedly enhanced. The loading of hippurate in the nanohybrid was estimated to be about 38.7% (w/w), and the release of hippurate from the nanohybrid was of a controlled manner, and therefore the resulting material was suitable for use as a controlled-release formulation. HAN has synergistic properties with tamoxifen toward a HepG2 cell line, with an IC 50 value of 0.35 compared with hippurate. In the antiproliferative assay, the ratio of viable cells account for cells treated by the combination tamoxifen with HAN to untreated cells was sharply reduced from 66% to 13% after 24 and 72 hours, respectively. The release of hippuric acid anions from HAN occurred in a controlled manner, and the resulting material is suitable for a controlled-release formulation

Preparation of chitosan nanoparticles as a drug delivery system for perindopril erbumine

Chitosan nanoparticles (CSNPs) and perindopril erbumine (PE)‐loaded chitosan nanoparticles (PE‐CSNPs) were prepared using the ionic gelation method with tripolyphosphate (TPP) as a crosslinking agent. The XRD pattern of the PE‐CSNP nanocomposite shows suppression of the peaks corresponding to crystallized chitosan due to its conversion to the amorphous form after crosslinking and PE loading. The presence of the drug in the nanocomposite was confirmed by a shift in the FTIR transmittance peak from 1,289 to 1,279 cm−1. The mean diameter of the PE‐CSNP nanocomposite was 44 nm. Analysis of the ultraviolet spectrum indicated that the loading efficiency and the encapsulation efficiency were 30.5% and 94.1%, respectively. The in vitro drug release profile was also determined by ultraviolet spectroscopy, which showed a sustained release over a period of 2 h (99.8%), starting with initial burst release (40% in 10 min). According to our results, no IC50 (the half maximal inhibitory concentration) against the 3T3 cell line was found for free PF or the PE‐CSNP nanocomposite up to 100 μg mL−1

TRANSDERMAL OF ATENOLOL VIA MICROEMULSIONS

Objective: Developing novel non-ionic microemulsions (MEs) for transdermal of atenolol as satisfactory alternative drug delivery systems for the oral route. Methods: Seven MEs were developed then checked for encapsulation of atenolol using Fourier Transform Infrared Spectroscopy (FTIR-spectroscopy) (), isotropy, droplet sizes, rheological properties and transdermal flux using Franz diffusion cell. Furthermore, two MEs with best flux values were selected for bioavailability evaluation after transdermal application over rat’s skin. Results: The results showed that the MEs complies with colloidal systems properties. Also, the developed MEs were stable throughout the study, ideal viscous systems with droplet sizes below 500 nm and isotropic. Besides, FTIR-spectra could reveal the structure of the MEs and encapsulation of atenolol inside the dispersed phase. Moreover, the flux values of atenolol in MEs through rat’s skin varied with different factors such as atenolol concentration, MEs’s composition, and zetapotential. The highest flux value of the developed systems was 243.5±16.3 µg. cm-2. h-1. Furthermore, the in vivo results showed that using the two tested microemulsions maximum plasma levels of atenolol 5.22±0.43 and 4.06±0.15 mg. ml-1at 8.18 and 3.64 h respectively could be achieved. Conclusion: The developed microemulsions can be promise formulations for transdermal administration of atenolol as alternative for oral tablets

The in vitro therapeutic activity of ellagic acid-alginate-silver nanopeprintss on breast cancer cells (MCF-7) and normal fibroblast cells (3T3)

The present work involves the development of EA-Alg-AgNPs nanocomposite based on ellagic acid (EA) as active compound. Silver nitrate was taken as the metal precursor (AgNPs) and sodium alginate (Alg) as a reducing agent. The EA-Alg-AgNPs nanocomposite was characterized using transmission electron microscopy (TEM), zeta potential, and in vitro release kinetics. The particles thus obtained were spherical in shape and having an average particles size of 10 nm, zeta potentials of –8.2 mV, and the release kinetics of EA from nanocomposite was following Hixson-Crowell kinetics models with R 2 = 0.9956. The cytotoxicity potential of free EA, Alg-AgNPs and the EA-Alg-AgNPs nanocomposite may be determined using a normal mouse fibroblast cells (3T3) and breast cancer cells (MCF-7). EA-Alg-AgNPs nanocomposite demonstrated a increased cytotoxicity effect when compared to free EA on MCF-7 cells with 15.3% cell viability at 128 μg/mL; compared to 33.5% cell viability in a direct EA exposure. It is worth mentioning the cytotoxicity of Alg-AgNPs against MCF-7 shows 28% viability at 128 μg/mL