Preparation of Sterile Raw Material - Chicken Eggshells in the Process of their Transformation into Selected Calcium Salts.

BACKGROUND: The chicken eggshells and their subcrustal membranes are a valuable source of calcium, but they are not further processed but disposed of as waste from the food industry. Chicken eggshells have high content (>95%) of calcium carbonate. Some properties suggest that eggshells may be a promising alternative to the present calcium sources used in the pharmaceutical industry. METHODS: The effect of roasting chicken eggshells with a selected organic acid (citric or fumaric or lactic acid) on microbiological purity, including the presence of fungi and bacteria Salmonella spp., Staphylococcus aureus, Escherichia coli of obtained calcium salts, was investigated. In this study, chicken eggshells were subjected to chemical reactions with organic acids (citric, fumaric or lactic acid) at two different calcium-acid molar ratios (1:1 or 1:3) and the mixture was heat-treated for 1 or 3 hours at a temperature of 100°C or 120°C. RESULTS AND DISCUSSION: It was found that lactic acid was 100% effective against fungi, and the remaining citric and fumaric acids were -50% (regardless of the other examined conditions). The type of acid used has a significant effect on fungal growth inhibition (p<0.05). Fumaric acid and lactic acid will be nearly 100% effective against bacteria (100% fumaric acid and 97% lactic acid effectiveness), regardless of other factors. CONCLUSION: Lactic acid is the most effective against pathogenic flora - fungi and bacteria. The transformation of chicken eggshells into calcium lactate can provide us with sterile calcium salt, free of 100% fungi and 97% of all bacteria.

Biomimetic activity of soluble, well-defined, aqueous Ti(IV)-citrate species toward adipogenesis. An in vitro study.

Metal-organic complexes bearing physiological substrates have been the target of several investigations, probing into the potential of well-defined atoxic metalloforms to influence fundamental cellular processes overcoming insulin resistance in Diabetes mellitus 2. Outstanding cases of such metals include zinc and vanadium, both being the target of intense synthetic and biological studies toward insulin mimesis. Owing to the close proximity in the periodic table, an early transition metal, titanium, emerges as another potential candidate of biologically relevant complexation, reflecting species capable of promoting insulin mimetic activity. Driven by the so far explored aqueous synthetic chemistry of Ti(IV)-hydroxycaboxylato systems, a well-defined Ti(IV)-citrate compound was synthesized under physiological conditions, isolated, and characterized, followed by its introduction in biological assays, targeting adipogenic events linked to glucose uptake and catabolism. The mononuclear Ti(IV)-citrate complex was introduced to 3T3-L1 cells, thereby probing into its biological activity (toxicity, morphology, migration, and adipogenic capacity). The results project an atoxic profile for the Ti(IV)-citrate species, thus justifying further incorporation in cellular differentiation processes, leading to mature adipocytes in a time- and concentration-dependent fashion. The experiments suggest that Ti(IV)-citrate is a competent agent promoting fibroblast differentiation, as evidenced by key adipogenic biomarkers, while concurrently exhibiting synergistic/enhancing action with insulin. The collective results show, for the first time, that an appropriately configured soluble-bioavailable complex Ti(IV) form exhibits a distinctly unique bioprofile, thereby lending credence to the notion that titanium metallopharmaceuticals hold merit as competent agents in adipogenesis and insulin mimesis in Diabetes mellitus.

Preparation and characterization of citric acid crosslinked konjac glucomannan/surface deacetylated chitin nanofibers bionanocomposite film.

Novel bionanocomposite films were prepared by combining konjac glucomannan/surface deacetylated chitin nanofibers (KGM/S-ChNFs) with different concentrations of citric acid (CA) (10%-25%) via a solution casting method. The effect of CA-induced crosslinking on the rheological behavior of film-forming solutions (FFS) as well as the structural and physicochemical properties of the resulting bionanocomposite films were evaluated. The results revealed that the increased CA loadings increased the shear viscosity of FFS. Fourier transform infrared spectra and scanning electron microscopy results confirmed the successful crosslinking between CA and S-ChNFs. The addition of 20 wt% CA was defined as the optimal condition, resulting in minimum water sensitivity and permeability, while maintaining a good combination of tensile strength and antimicrobial properties. This work supported the conclusion that CA crosslinking was an effective pathway for the preparation of polysaccharide-based bionanocomposite films with improved properties, which may be a promising material for active food packaging applications.

Synthesis of natural deep eutectic solvents using a mixture design for extraction of animal and plant samples prior to ICP-MS analysis.

Solvents with both low density and viscosity have the advantage of higher extraction efficiency due to lower diffusivity and consequently higher mass transfer. In this study, a mixture design was performed for the synthesis of three different natural deep eutectic solvents (NADES) using citric acid, malic acid, and xylitol. The optimized proportion for each of the three solvents synthesized was selected based on density and viscosity values. The NADES were characterized by infrared spectroscopy analysis, that showed characteristic bands of the initial reagents and the presence of hydrogen bonds confirming the formation of each deep eutectic solvent. Then, the NADES were used as solvents in ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) of biological tissue and plant material samples for the determination of As, Cd, Hg, Pb, Se, and V by inductively coupled plasma mass spectrometry (ICP-MS). The results for the proposed methods were compared to microwave-assisted acid digestion (MW-AD). The extraction recoveries ranged from 80 to 120% for most of the elements determined. The use of NADES as carbon sources improved the sensitivity of the As and Cd analyses, due to charge transfer reactions between the analyte and C+ and/or other carbon species. In addition, the Analytical Eco-Scale was used to assess the greenness of the proposed analytical procedures (UAE and MAE). It showed that the UAE and MAE methods provided excellent green analyses, while the MW-AD method was rated as an acceptable green procedure.

Citric acid functionalized silane coupling versus post-grafting strategy for dual pH and saline responsive delivery of cisplatin by Fe3O4/carboxyl functionalized mesoporous SiO2 hybrid nanoparticles: A-synthesis, physicochemical and biological characterization.

Synthesis of monodisperse carboxylic acid-functionalized magnetic mesoporous silica nanoparticles is performed by either two-step sol-gel process or post-grafting using citric acid modified isocyanate silane coupling agent (MMSN-NCO-CA) or succinic anhydride modified magnetic mesoporous silica (MMSN-NH-SA). Morphology, structure and magnetic properties of bare and mesoporous silica coated Fe3O4 core were studied using various techniques such as FTIR, VSM, TEM, FESEM, XRD and N2 adsorption-desorption isotherms (BET). Cisplatin (cis-Pt) adsorption isotherms and its release profile in various media were investigated by ICP-OES. MMSN-NCO-CA with mean particle size 107 nm had lower surface area (87.5 m2/g) and larger pore size (6.9 nm) in comparison with MMSN-NH-SA (respective values of 151.2 m2/g and 3.5 nm). cis-Pt loading into particles followed a saturable adsorption with respect to the drug to particle mass ratios. More sustained release of cis-Pt was observed for MMSN-NCO-CA, though both nanoparticles exhibited a pH- and saline concentration-dependent drug release. In addition, general and cis-Pt specific cytotoxicity were examined by MTT assay in MDA-MB-231 breast cancer cell line, and to further detect apoptosis, acridine orange/ethidium bromide dual cell staining was investigated by fluorescence microscopy. In-vitro anti-tumor efficiency of cis-Pt loaded MMSN-NCO-CA and MMSN-NH-SA were similarly enhanced in comparison to free cis-Pt; however, more specific apoptotic death occurred for cis-Pt loaded MMSN-NCO-CA. Therefore, the as-synthesized citric acid functionalized core-shell magnetic mesoporous hybrid nanoparticles could be used as a promising drug carriers for cancer therapy in-vivo.

Natural deep eutectic solvents for sample preparation prior to elemental analysis by plasma-based techniques.

Natural deep eutectic solvents (NADES) based on xylitol, citric acid, and malic acid were synthesized and were then characterized using infrared spectroscopy, thermogravimetry (TG), differential scanning calorimetry (DSC), also density and viscosity were measurements. The deep eutectic solvents were used as solvent in ultrasound-assisted extraction (DES-UAE) of plant samples prior to elemental analysis. Inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP OES) were employed for the determination of As, Ca, Cd, Cu, Fe, K, Mg, Mn, Na, P, and Zn in the extracts. The infrared analyses of the NADES revealed bands characteristic of the initial reagents, with the presence of hydrogen bonds, which confirmed the formation of a NADES. The thermal analyses showed decomposition temperatures of around 170 °C and endothermic events related to degradation of the NADES. The viscosity and density parameters were found to be related to the presence of hydrogen bonds. The extraction recoveries ranged from 80% to 120%, with some analytes presenting poor recoveries. There were no significant differences between the NADES, in terms of the concentrations of the analytes found in the extracts. However, there were differences between the analyte concentrations obtained using the NADES extraction method and the concentrations obtained using microwave-assisted acid digestion (MW-AD), possibly due to the different types of interactions between the solvents and the analytes. Plant tissues are complex matrices containing substantial amounts of silica, so some elements may be tightly bound and consequently difficult to release. The results indicated that UAE using NADES is a promising technique for the elemental extraction of plant samples.

Production of high titer of citric acid from inulin.

BACKGROUND: Citric acid is considered as the most economically feasible product of microbiological production, therefore studies on cheap and renewable raw materials for its production are highly desirable. In this study citric acid was synthesized by genetically engineered strains of Yarrowia lipolytica from widely available, renewable polysaccharide - inulin. Hydrolysis of inulin by the Y. lipolytica strains was established by expressing the inulinase gene (INU1 gene; GenBank: X57202.1) with its native secretion signal sequence was amplified from genomic DNA from Kluyveromyces marxianus CBS6432. To ensure the maximum citric acid titer, the optimal cultivation strategy-repeated-batch culture was applied. RESULTS: The strain Y. lipolytica AWG7 INU 8 secreted more than 200 g dm- 3 of citric acid during repeated-batch culture on inulin, with a productivity of 0.51 g dm- 3 h- 1 and a yield of 0.85 g g- 1. CONCLUSIONS: The citric acid titer obtained in the proposed process is the highest value reported in the literature for Yarrowia yeast. The obtained results suggest that citric acid production from inulin by engineered Y. lipolytica may be a very promising technology for industrial citric acid production.

Continuous manufacturing of orally dissolving webs containing a poorly soluble drug via electrospinning.

An orally dissolving web (ODW) formulation of poorly soluble carvedilol (CAR) was developed and manufactured continuously using electrospinning (ES) as a key technology. Phase solubility tests revealed that hydroxypropyl-ß-cyclodextrin (HPßCD) solubilizer alone cannot ensure sufficient solubility (6.25 mg CAR in 20 mL) in the oral cavity even if citric acid was present to ionize the basic drug. In turn, electrospun amorphous nanofibers of polyvinylpyrrolidone K30 (PVPK30) and CAR exhibited notable supersaturation of the drug in the presence of citric acid. Differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD) confirmed the amorphous state of CAR. The final ODW was prepared by layering the nanofibers onto pullulan, a well-soluble polysaccharide film carrying citric acid. The double-layered formulation showed ultrafast disintegration and dissolution modeling the oral cavity meeting regulatory requirements (<30 s). The continuous production was accomplished using our recently developed continuous model system by controlled deposition of the nanofibers onto the carrier film strained to a wheel collector and followed by cutting into final dosage units. Performance tests of the continuous system revealed satisfactory content uniformity over time (average acceptance value = 9.45), while residual solvent content measurements showed trace amounts of ethanol (EtOH) after production and acceptable dimethyl-formamide (DMF) content with secondary drying at room temperature. The presented work demonstrates how ES can be part of a continuous manufacturing system as an advanced drying tool during the formulation of challenging drugs.

Click chemistry improved wet adhesion strength of mussel-inspired citrate-based antimicrobial bioadhesives.

For the first time, a convenient copper-catalyzed azide-alkyne cycloaddition (CuAAC, click chemistry) was successfully introduced into injectable citrate-based mussel-inspired bioadhesives (iCMBAs, iCs) to improve both cohesive and wet adhesive strengths and elongate the degradation time, providing numerous advantages in surgical applications. The major challenge in developing such adhesives was the mutual inhibition effect between the oxidant used for crosslinking catechol groups and the Cu(II) reductant used for CuAAC, which was successfully minimized by adding a biocompatible buffering agent typically used in cell culture, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), as a copper chelating agent. Among the investigated formulations, the highest adhesion strength achieved (223.11 ± 15.94 kPa) was around 13 times higher than that of a commercially available fibrin glue (15.4 ± 2.8 kPa). In addition, dual-crosslinked (i.e. click crosslinking and mussel-inspired crosslinking) iCMBAs still preserved considerable antibacterial and antifungal capabilities that are beneficial for the bioadhesives used as hemostatic adhesives or sealants for wound management.

Total synthesis of alkyl citrate natural products.

This review highlights the synthesis of members of the alkyl citrate family of natural products. The focus is on the stereoselective construction of the alkyl citrate moiety common to these compounds.

Mn-citrate and Mn-HIDA: intermediate-affinity chelates for manganese-enhanced MRI.

In this study we investigated two manganese chelates in order to improve the image enhancement of manganese-enhanced MRI and decrease the toxicity of free manganese ions. Since both MnCl2 and a low-affinity chelate were associated with a slow continuous decrease of cardiac functions, we investigated intermediate-affinity chelates: manganese N-(2-hydroxyethyl)iminodiacetic acid (Mn-HIDA) and Mn-citrate. The T1 relaxivity values for Mn-citrate (4.4 m m⁻¹ s⁻¹) and Mn-HIDA (3.3 m m⁻¹ s⁻¹) in artificial cerebrospinal fluid (CSF) were almost constant in a concentration range from 0.5 to 5 m m at 37 °C and 4.7 T. In human plasma, the relaxivity values increased when the concentrations of these Mn chelates were decreased, suggesting the presence of free Mn²âº bound with serum albumin. Mn-HIDA and Mn-citrate demonstrated a tendency for better contractility when employed with an isolated perfused frog heart, compared with MnCl2. Only minimal changes were demonstrated after a venous infusion of 100 m m Mn-citrate or Mn-HIDA (8.3 µmol kg⁻¹ min⁻¹) in rats and a constant heart rate, arterial pressure and sympathetic nerve activity were maintained, even after breaking the blood-brain barrier (BBB). Mn-citrate and Mn-HIDA could not cross the intact BBB and appeared in the CSF, and then diffused into the brain parenchyma through the ependymal layer. The responses in the supraoptic nucleus induced by the hypertonic stimulation were detectable. Therefore, Mn-citrate and Mn-HIDA appear to be better choices for maintaining the vital conditions of experimental animals, and they may improve the reproducibility of manganese-enhanced MRI of the small nuclei in the hypothalamus and thalamus.

Development of biodegradable flexible films of starch and poly(lactic acid) plasticized with adipate or citrate esters.

Biodegradable films were produced from blends contained a high amount of thermoplastic starch (TPS) and poly(lactic acid) (PLA) plasticized with different adipate or citrate esters. It was not possible to obtain pellets for the production of films using only glycerol as a plasticizer. The plasticization of the PLA with the esters and mixture stages added through extrusion was critical to achieve a blend capable of producing films by blow extrusion. Adipate esters were the most effective plasticizers because they interacted best with the PLA and yielded films with appropriate mechanical properties.

Detection and formation scenario of citric acid, pyruvic acid, and other possible metabolism precursors in carbonaceous meteorites.

Carbonaceous meteorites deliver a variety of organic compounds to Earth that may have played a role in the origin and/or evolution of biochemical pathways. Some apparently ancient and critical metabolic processes require several compounds, some of which are relatively labile such as keto acids. Therefore, a prebiotic setting for any such individual process would have required either a continuous distant source for the entire suite of intact precursor molecules and/or an energetic and compact local synthesis, particularly of the more fragile members. To date, compounds such as pyruvic acid, oxaloacetic acid, citric acid, isocitric acid, and α-ketoglutaric acid (all members of the citric acid cycle) have not been identified in extraterrestrial sources or, as a group, as part of a "one pot" suite of compounds synthesized under plausibly prebiotic conditions. We have identified these compounds and others in carbonaceous meteorites and/or as low temperature (laboratory) reaction products of pyruvic acid. In meteorites, we observe many as part of three newly reported classes of compounds: keto acids (pyruvic acid and homologs), hydroxy tricarboxylic acids (citric acid and homologs), and tricarboxylic acids. Laboratory syntheses using (13)C-labeled reactants demonstrate that one compound alone, pyruvic acid, can produce several (nonenzymatic) members of the citric acid cycle including oxaloacetic acid. The isotopic composition of some of the meteoritic keto acids points to interstellar or presolar origins, indicating that such compounds might also exist in other planetary systems.

Citric acid-derived in situ crosslinkable biodegradable polymers for cell delivery.

Herein, we report a first citric acid (CA)-derived in situ crosslinkable biodegradable polymer, poly(ethylene glycol) maleate citrate (PEGMC). The synthesis of PEGMC could be carried out via a one-pot polycondensation reaction without using organic solvents or catalysts. PEGMC could be in situ crosslinked into elastomeric PPEGMC hydrogels. The performance of hydrogels in terms of swelling, degradation, and mechanical properties were highly dependent on the molar ratio of monomers, crosslinker concentration, and crosslinking mechanism used in the synthesis process. Cyclic conditioning tests showed that PPEGMC hydrogels could be compressed up to 75% strain without permanent deformation and with negligible hysteresis. Water-soluble PEGMC demonstrated excellent cytocompatibilty in vitro. The degradation products of PPEGMC also showed minimal cytotoxicity in vitro. Animal studies in rats clearly demonstrated the excellent injectability of PEGMC and degradability of the in situ-formed PPEGMC. PPEGMC elicited minimal inflammation in the early stages post-injection and was completely degraded within 30 days in rats. In conclusion, the development of CA-derived injectable biodegradable PEGMC presents numerous opportunities for material innovation and offers excellent candidate materials for in situ tissue engineering and drug delivery applications.

Synthesis of citrate-ciprofloxacin conjugates.

Two regioisomeric citrate-functionalized ciprofloxacin conjugates have been synthesized and their antimicrobial activities against a panel of clinically-relevant bacteria have been determined. Cellular uptake mechanisms were investigated using wild-type and ompF deletion strains of Escherichia coli K-12.

Enhancing the functionality of biobased polyester coating resins through modification with citric acid.

Citric acid (CA) was evaluated as a functionality-enhancing monomer in biobased polyesters suitable for coating applications. Model reactions of CA with several primary and secondary alcohols and diols, including the 1,4:3,6-dianhydrohexitols, revealed that titanium(IV) n-butoxide catalyzed esterification reactions involving these compounds proceed at relatively low temperatures, often via anhydride intermediates. Interestingly, the facile anhydride formation from CA at temperatures around CA's melting temperature ( T m = 153 degrees C) proved to be crucial in modifying sterically hindered secondary hydroxyl end groups. OH-functional polyesters were reacted with CA in the melt between 150 and 165 degrees C, yielding slightly branched carboxylic acid functional materials with strongly enhanced functionality. The acid/epoxy curing reaction of the acid-functional polymers was simulated with a monofunctional glycidyl ether. Finally, the CA-modified polyesters were applied as coatings, using conventional cross-linking agents. The formulations showed rapid curing, resulting in chemically and mechanically stable coatings. These results demonstrate that citric acid can be applied in a new way, making use of its anhydride formation to functionalize OH-functional polyesters, which is an important new step toward fully biobased coating systems.

Synthesis, spectral properties, and antitumor activity of a new axially substituted phthalocyanine complex of zirconium(IV) with citric acid.

The new axially substituted phthalocyanine (pc) complex of zirconium(IV) with citric acid is reported. It has been shown that the replacement of two Cl-atoms with two citric acid fragments takes place as the result of the reaction between [ZrCl2(pc)] and citric acid. The complex [Zr(citrate)2(pc)] was formed. The spectroscopic properties of the synthesized compound in DMSO, RPMI 1640 medium with and without fetal calf serum (FCS), H2O, and buffer (Tris) solutions have been described. Antitumor activity of this compound has been studied. The cytostatic activity was observed in the concentration range of 6.1-9.0x10(9) molecules [Zr(citrate)2(pc)]/cell and occurred in 4-6 h after treatment with [Zr(citrate)2(pc)] solution.

Attempts at improving citric acid fermentation by Aspergillus niger in beet-molasses medium.

Natural oils with high unsaturated fatty acids content when added at concentrations of 2% and 4% (v/v) to beet molasses (BM) medium caused a considerable increase in citric acid yield from Aspergillus niger. The fermentation capacities were also examined for production of citric acid using BM-oil media under different fermentation conditions. Maximum citric acid yield was achieved in surface culture in the presence of 4% olive oil after 12 days incubation.

Microbial production of citric acid

O ácido cítrico é o ácido mais produzido em termos de tonagem e é extensivamente utilizado pelas indústrias alimentícia e farmacêutica. É produzido principalmente por fermentaçäo submersa utilizando o fungo Aspergillus niger e leveduras do gênero Candida sp. à partir de diferentes forntes de carbono, como a glicose e meios à base de amido. No entanto, outras técnicas de fermentaçäo, e.g. fermentaçäo no estado sólido e em superfície, e fontes alternativas de carbono tem sido intensamente estudadas mostrando grande perspectivas para o processo. O presente trabalho apresenta um resumo dos últimos avanços sobre a produçäo do ácido cítrico, descrevendo de maneira sucinta os trabalhos mais recentes, descrevendo microorganismos, técnicas de produçäo e substratos empregados, etc