Sodium Caprylate Research Articles

Sodium caprylate induced precipitation post Protein A chromatography as an effective means for host cell protein clearance

In downstream processing of monoclonal antibody (mAb), post Protein A neutralization and subsequent intermediate depth filtration are critical steps for host cell protein (HCP) clearance. Previous studies have shown that adding caprylic acid (CA) during neutralization can further improve HCP removal by promoting their precipitation. In this study, we replaced CA with its sodium salt – sodium caprylate (SC). For the five mAbs studied, SC has been shown to be equally effective as CA at precipitating HCPs. As the salt form has a higher solubility, SC stock solution with relatively high concentration can be easily prepared, which facilitates its adding to the Protein A elution pool. Thus, this study not only confirms the effectiveness of CA/SC-induced HCP precipitation but also provides a more convenient way to integrate this method into the downstream process.

Maternal short and medium chain fatty acids supply during early pregnancy improves embryo survival through enhancing progesterone synthesis in rats

Exploring strategies to prevent miscarriage in women or early pregnancy loss in mammals is of great importance. Manipulating maternal lipid metabolism to maintain sufficient progesterone level is an effective way. To investigated the embryo loss and progesterone synthesis impacts of short and medium chain fatty acids on the lipid metabolism, pregnancy outcome and embryo implantation were investigated in rats fed the pregnancy diets supplemented without or with 0.1% sodium butyrate (SB), 0.1% sodium hexanoate (SH), or 0.1% sodium caprylate (SC) during the entire pregnancy and early pregnancy, respectively, followed with evaluation of potential mechanisms. Maternal SB, SH, or SC supply significantly improved live litter size and embryo implantation in rats. Serum progesterone, arachidonic acid, and phospholipid metabolites levels were significantly increased in response to maternal SB, SH, and SC supply. The expression of key genes involved in ovarian steroidogenesis and granulosa cell luteinization were elevated in ovaries and primary cultured granulosa cells, including cluster of differentiation 36 (CD36), steroidogenic acute regulatory protein (StAR), and cholesterol side-chain cleavage enzyme (CYP11A1). Additionally, the expression of lysophosphatidic acid receptor 3 (LPA3) and cyclooxygenase-2 (COX2) related with phospholipid metabolism were enhanced in uterus in vivo and in in vitro cultured uterine tissue. In conclusion, maternal SB, SH and SC supply reduced early pregnancy loss through modulating maternal phospholipid metabolism and ovarian progesterone synthesis in rats. Our results have important implications that short or medium chain fatty acids have the potential to prevent miscarriage in women or early pregnancy loss in mammals.

Effect of tocopherol on the properties of Pluronic F127 microemulsions: Physico-chemical characterization and in vivo toxicity

The development of biodegradable and biocompatible microemulsions to transport and deliver hydrophobic bioactive molecules is a fundamental challenge in pharmacological sciences. In the current work, oil-in-water Pluronic F127-based microemulsions using different fatty acids (sodium decanoate, SD, and sodium caprylate, SC) as co-surfactants were characterized as potential nanocarriers to solubilize and transport tocopherol (TOC) at Ow = [ethyl butyrate] / [Pluronic] = 1 and oil nanodroplet mass fraction (MFD) between 0.01 and 0.08 using dynamic light scattering (DLS) and dynamic surface tension (DST) techniques. DLS data showed that as the fatty acid chain length increased from sodium decanoate (SD) to sodium caprylate (SC), the nanodroplet size also did whereas the opposite behaviour was found as the MFD increased. DST data revealed that surface tension reached much faster the thermodynamic equilibrium for SD-stabilized compared to SC-stabilized Pluronic F127-based microemulsions. These were able to load important amounts of TOC with a high encapsulation efficiency. The release profile of the cargo compound from the microemulsions was sustained along time. In addition,2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity of TOC was examined, and results reported as the half maximal inhibitory concentration (IC50) values. Finally, to evaluate the potential cytotoxicity of the obtained TOC-loaded microemulsions preliminary in vivo experiments were performed. Microemulsions were parenterally administered in healthy rats and blood was collected to analyze serum levels of alanine aminotransferase (ALT), serum aspartate aminotransferase (AST), serum creatinine, serum blood urea nitrogen (BUN) and lactate dehydrogenase (LDH). Experimental data indicated a significant decrease in serum BUN and creatinine levels while other parameters remained unchanged. Also, the drug-loaded microemulsions-treated group showed symptoms of lethargy, nausea, and reduced food intake following injection, but no mortality was reported.

Novel application of mixed solvency concept in the development of oral liquisolid system of a poorly soluble drug, cefixime and its evaluation

Application of mixed solvency has been employed in the present research work to develop a liquisolid system (Powder formulation) of poorly water soluble drug, cefixime (as model drug). Material and Methods: For poorly water soluble drug cefixime, combination of solubilizers such as sodium acetate, sodium caprylate and propylene glycol as mixed solvent systems were used to decrease the overall concentration of solubilizers required to produce substantial increase in solubility and thereby resulting in enhanced drug loading capacity of cefixime. The procured sample of cefixime was characterized by melting point, IR, UV and DSC studies. Stability studies of liquisolid system of cefixime were performed for two months at room temperature, 30˚C and 40˚C. All the formulations were physically, chemically, and microbiologically stable. Conclusion: Mixed solvency concept has been successfully employed for enhancing the drug loading of poorly water soluble drug, cefixime.
 Keywords: Solubility, cefixime, liquisolid system, mixed solvency concept.

Formulation and development of fast dissolving oral film of a poorly soluble drug, frusemide with improved drug loading using mixed solvency concept and its evaluation

The aim of the present research work is to explore the application of mixed solvency concept to formulate and develop a fast dissolving oral film of furosemide with improved drug loading. In the present study, poorly soluble drug, furosemide was tried to be solubilized by employing the combination of physiologically compatible water-soluble additives (solubilizers) to formulate its fast dissolving formulations. For the development of fast dissolving oral film, firstly, different film forming polymers were tested for their film properties. The second fast dissolving layer was also formed and optimized. Solubility studies were conducted to select water-soluble additives for formulation of fast dissolving drug layer. Keeping the total concentration less than 40 % w/v of mixed blends, different aqueous blends were prepared employing solubilizers from among sodium benzoate, sodium acetate, sodium citrate, urea, niacinamide, glycerin, propylene glycol, polyethylene glycol 200, polyethylene glycol 400, polyethylene glycol 600, and PVP K 30. Maximum solubility of furosemide was found in blends- F5 (10% sodium caprylate +2.5%sodium benzoate+ 2.5% niacinamide) and in blend F7 (10% sodium caprylate +2.5%sodium benzoate +2.5% sodium citrate + 2.5% niacinamide). Prepared films were evaluated for drug content, thickness, folding endurance, tensile strength and hydration ratio.
 Keywords: Furosemide, fast dissolving oral film, mixed solvency concept.

Formulation and development of vaginal films of poorly water soluble drug, metronidazole, using mixed solvency concept and their evaluations

Aim: To deliver antibacterial therapy in an efficacious way, film dosage form has been proposed for drug delivery in vagina which can overcome bioavailability issues of poorly water soluble drugs. The present research work is aimed to explore the application of mixed solvency concept to increase solubility of poorly water soluble drug, metronidazole. Materials and Methods: Metronidazole, a slightly soluble drug in water was tried to be solubilized by employing the combination of solubilizers like niacinamide, sodium benzoate, sodium caprylate, caffeine and urea to endeavour its fast dissolving film formulations. The procured sample of drug was characterized by UV, IR and DSC studies. The formulations were evaluated for various properties of film such as thickness, folding endurance, surface pH, disintegration time and thin layer chromatography. Stability studies of vaginal films of metronidazole were performed for ten weeks at room temperature, and refrigerated conditions. Results and Discussion: It was found that 97.54% and 97.58% of drug was remaining after stability study at respective temperatures in batch F1 and 98.53% and 96.57% in batch F4.Conclusion: It was concluded that the approach of mixed solvency concept is novel, safe, cost-effective and user friendly. It also eliminates the problem of toxicity associated with high concentration of water-soluble solubilizers. So, it may be employed in dosage form development of drugs with poor solubility to overcome bioavailability issues.
 Keywords: Solubility, metronidazole, vaginal films, mixed solvency concept.

Applications of Edible Coatings Formulated with Antimicrobials Inhibit Listeria monocytogenes Growth on Queso Fresco

Despite efforts to control Listeria monocytogenes in dairy processing environments, contamination and subsequent outbreaks of listeriosis continue to occur. The ability of L. monocytogenes to grow during refrigerated storage necessitates strategies to prevent contamination, reduce pathogen numbers, and limit growth during storage. The objective of this study was to determine the efficacy of edible antimicrobial coatings to control L. monocytogenes on Queso Fresco (QF) when applied before (pre-coated; PC) or after (pre-inoculated; PI) surface contamination. Coating solutions were formulated to contain 2% chitosan and either 5% hydrogen peroxide (HP), 5% lauric arginate (LAE), 25% acidified calcium sulfate with lactic acid (ACSL), or combinations of 10% sodium caprylate (SC) with either LAE or ACSL. Fresh QF samples (25g) were inoculated with L. monocytogenes at ~4 log CFU/g prior to, or following, antimicrobial coating application. Cheeses were then vacuum packaged and stored at 7°C for 35 days with weekly enumeration of L. monocytogenes. Aside from ACSL and LAE+SC, there was no effect of coating application timing (PC vs. PI) on the change in L. monocytogenes counts over time. Chitosan coatings without additional antimicrobials were more effective than controls but did not inhibit L. monocytogenes growth beyond 7 days. Coatings containing HP at 5% were equally effective when applied before or after L. monocytogenes inoculation, significantly reducing L. monocytogenes counts by more than 3 log CFU/g and inhibiting growth through 35 days of storage. Coatings formulated with ACSL at 25% were more effective when applied to pre-inoculated cheeses but neither application produced significant reduction in L. monocytogenes counts or inhibited growth. Although LAE coatings were more effective than ACSL, neither were more effective than chitosan coatings alone. The addition of SC to ACSL and LAE coatings enhanced their antimicrobial activity as ACSL+SC and LAE+SC coatings reduced L. monocytogenes counts by >1 log CFU/g after 24 hours and were listeristatic through 28 and 35 days, respectively. The identification of listericidal and listeristatic edible antimicrobial coating applications that are effective when applied before or after contamination events identifies a new approach for the control of L. monocytogenes on fresh cheese.

Removal of stabilizers from human serum albumin by adsorbents and dialysis used in blood purification.

IntroductionHuman serum albumin (HSA) is a monomeric multi-domain protein that possesses an extraordinary binding capacity. It plays an important role in storing and transporting endogenous substances, metabolites, and drugs throughout the human circulatory system. Clinically, HSA is used to treat a variety of diseases such as hypovolemia, shock, burns, hemorrhage, and trauma in critically ill patients. Pharmaceutical-grade HSA contains the stabilizers sodium caprylate and N-acetyltryptophanate to protect the protein from oxidative stress and to stabilize it for heat treatment which is applied for virus inactivation.Material and methodsThe aim of this study was to determine if the two stabilizers can be depleted by adsorbent techniques. Several, adsorbents, some of them are in clinical use, were tested in batch and in a dynamic setup for their ability to remove the stabilizers. Furthermore, the removal of the stabilizers was tested using a pediatric high flux dialyzer.ResultsThe outcome of this study shows that activated charcoal based adsorbents are more effective in removal of N-acetylthryptophanate, whereas polystyrene based adsorbents are better for the removal of caprylate from HSA solutions. An adsorbent cartridge which contains a mix of activated charcoal and polystyrene based material could be used to remove both stabilizers effectively. After 4 hours treatment with a high flux dialyzer, N-acetyltryptophanate was totally removed whereas 20% of caprylate remained in the HSA solution.

Efficacy of Antimicrobials Applied Individually and in Combination for Controlling Listeria monocytogenes as Surface Contaminants on Queso Fresco

Outbreaks of listeriosis are continually attributed to the consumption of Hispanic-style soft cheeses contaminated with Listeria monocytogenes postpasteurization. Once contaminated, L. monocytogenes can grow rapidly in cheeses like Queso Fresco (QF) even when stored at refrigeration temperatures. Several antimicrobials, including acidified calcium sulfate with lactic acid (ACSL), ε-polylysine (EPL), hydrogen peroxide (HP), lauric arginate ethyl ester (LAE), and sodium caprylate (SC), have demonstrated antilisterial activity in food. The objectives of this study were to determine the efficacy of these antimicrobials used individually and in combination to control L. monocytogenes as surface contaminants on QF and to identify additive and synergistic interactions. Cheeses were surface inoculated at ∼4 log CFU/g, dipped in antimicrobial solutions, vacuum packaged, and then stored at 7°C for 35 days. L. monocytogenes counts were determined 24 h after application of the antimicrobials and then weekly throughout storage. Dip treatments in a 5% (v/v) HP solution reduced L. monocytogenes counts to <0.5 log CFU/g within 24 h with no increase in counts through day 35. Dip treatments in LAE at 2 and 5% alone and in combination with EPL at 10% produced initial reductions in pathogen counts (1.5 to 1.8 CFU/g) but did not inhibit pathogen growth compared with the sterile water control. Dip applications of ACSL at 25% also produced an initial ∼1.5-log reduction in L. monocytogenes counts followed by regrowth. Application of SC at 10% alone and in combination with either EPL or LAE inhibited growth to <1 log CFU/g through 21 days of storage. The combination of ACSL+SC worked synergistically to inhibit the growth of L. monocytogenes on QF to <1 log CFU/g through 35 days. These data indicate that HP alone and treatments containing EPL, LAE, or ACSL in combination with SC are promising postlethality treatments and process controls for L. monocytogenes on QF through a 21-day shelf life.

Control of Listeria monocytogenes in whole milk using antimicrobials applied individually and in combination

Dairy product recalls and dairy-related illnesses are often the result of contamination with Listeria monocytogenes, which can occur throughout the dairy production and supply chains. The use of antimicrobial compounds is one practical approach for controlling pathogen survival and growth in foods. The goal of this study was to use fluid milk as a model system to identify listeristatic or listericidal treatments that show promise for application in fluid milk and for further evaluation in other dairy products (e.g., cheese). Caprylic acid (CA), ε-polylysine (EPL), hydrogen peroxide, lauric arginate (LAE), and sodium caprylate (SC) were added individually or in combination to whole milk inoculated with L. monocytogenes at ˜4 log10 cfu/mL. Samples were stored at 7°C for 21 d, and L. monocytogenes counts were determined weekly. Inhibitory concentrations of LAE (800 mg/L) and EPL (100-400 mg/L), as well as SC and CA (3,200 mg/L each), were identified. The addition of EPL at 800 mg/L reduced L. monocytogenes counts by >3 log10 cfu/mL from initial inoculation levels after 21 d. Addition of hydrogen peroxide to milk reduced counts by >3 log10 cfu/mL from initial inoculation within 24 h (400 and 800 mg/L) or by d 7 (200 mg/L). Although the combinatory treatments of EPL + CA, EPL + LAE, and LAE + SC were characterized as indifferent, EPL + SC worked synergistically to reduce L. monocytogenes populations in milk over 21 d. Overall, these data identify potential antimicrobial treatments to control L. monocytogenes in milk and serve as a foundation for the continued development of antimicrobial controls for L. monocytogenes in dairy products.

Synergistic Antimicrobial Combinations Inhibit and Inactivate Listeria monocytogenes in Neutral and Acidic Broth Systems

The use of antimicrobial compounds can be an effective approach to control Listeria monocytogenes in ready-to-eat foods, but it can also be limited by cost, restrictions on concentrations in foods, and potential changes to organoleptic properties. Combinatorial approaches that produce additive or synergistic effects allow for reductions in individual antimicrobial concentrations while achieving the same level of control. The present study determined the MIC and MBC of an antimicrobial compound when used alone or in binary combinations against L. monocytogenes in growth media adjusted to pH values 7.4 and 5.5 and characterized interactions as synergistic, additive, or antagonistic. Inhibitory and bactericidal concentrations were defined as changes in L. monocytogenes counts of ≤1.0 or ≥3.0 log CFU/mL compared with the starting inoculum, respectively. Individually, lauric arginate (LAE), hydrogen peroxide (HP), and ε-polylysine (EPL) inhibited L. monocytogenes growth at the lowest concentrations when applied alone in broth adjusted to pH 7.4. Similarly, LAE, EPL, and HP had the lowest MBCs in broth adjusted to both pH levels. The inhibitory efficacy of both caprylic acid and sodium caprylate (SC) increased at the lower pH, with reductions in MICs of >98%. In total, 35 and 19 additive or synergistic inhibitory and bactericidal combinations were identified at pH values 7.4 and 5.5, respectively. Combinations of acidified calcium sulfate with lactic acid (ACSL) and SC were among the most synergistic inhibitory groupings at both pH levels, whereas EPL+LAE were the most effective bactericides at pH 7.4. Combinations of SC with EPL or ACSL were also among the most effective bactericides at pH 5.5. These data serve as a foundation for developing more effective antimicrobial approaches for the control of L. monocytogenes in foods with different pH levels.

A Chromatographic Method for Assay of Sodium Caprylate in the Formulation “Albumin, Solution for Infusions”

A method for assaying sodium caprylate content using gel filtration HPLC and recording of the refractometric detector signal is described. Validation studies demonstrated the suitability of the method. Inclusion of a spectrophotometer in the chromatography system provided for monitoring two parameters (“Sodium caprylate” and “Polymers and aggregates”) in a single test.

Effect of surfactant chain length on drug release kinetics from microemulsion-laden contact lenses

The effect of surfactant chain lengths [sodium caprylate (C8), Tween 20 (C12), Tween 80 (C18)] and the molecular weight of block copolymers [Pluronic F68 and Pluronic F 127] were studied to determine the stability of the microemulsion and its effect on release kinetics from cyclosporine-loaded microemulsion-laden hydrogel contact lenses in this work. Globule size and dilution tests (transmittance) suggested that the stability of the microemulsion increases with increase in the carbon chain lengths of surfactants and the molecular weight of pluronics. The optical transmittance of direct drug-laden contact lenses [DL-100] was low due to the precipitation of hydrophobic drugs in the lenses, while in microemulsion-laden lenses, the transmittance was improved when stability of the microemulsion was achieved. The results of in vitro release kinetics revealed that drug release was sustained to a greater extent as the stability of microemulsion was improved as well. This was evident in batch PF127-T80, which showed sustained release for 15days in comparison to batch DL-100, which showed release up to 7days. An in vivo drug release study in rabbit tear fluid showed significant increase in mean residence time (MRT) and area under curve (AUC) with PF-127-T80 lenses (stable microemulsion) in comparison to PF-68-SC lenses (unstable microemulsion) and DL-100 lenses. This study revealed the correlation between the stability of microemulsion and the release kinetics of drugs from contact lenses. Thus, it was inferred that the stable microemulsion batches sustained the release of hydrophobic drugs, such as cyclosporine from contact lenses for an extended period of time without altering critical lens properties.

Multiple response optimization of heat shock process for separation of bovine serum albumin from plasma

ABSTRACTBovine serum albumin produced by heat shock from bovine plasma has been researched for the effects of sodium caprylate concentration [Cap], temperature (T), and pH on yield (Yield%) and purity (BSA%). Response surface methodology and desirability function approaches were applied to optimize its process. The best compromise solution was found with BSA% = 95.0 and Yield% = 28.5 for a [Cap] = 2 mM, T = 67.9°C, and pH = 5. A Monte Carlo simulation showed that it is possible to obtain excellent values for each individual response. However, a techno-economic feasibility study must be carried out to determine which one is the best option.

Interactions of human serum albumin with doxorubicin in different media

Interactions of human serum albumin (10wt% H2O and 0.3wt% sodium caprylate) with doxorubicin hydrochloride (1wt%) were studied alone or with addition of HCl (3.6wt% HCl) using 1H NMR spectroscopy. A model of hydrated HSA/12DOX was calculated using PM7 method with COSMO showing large variations in the binding constant depending on structural features of DOX/HSA complexes. DOX molecules/ions displace bound water from narrow intramolecular voids in HSA that leads to diminution of freezing-melting point depression of strongly bound water (SBW). Structure of weakly bound water (WBW) depends much weaker on the presence of DOX than SBW because a major fraction of DOX is bound to adsorption sites of HSA. Addition of HCl results in strong changes in structure of macromolecules and organization of water in hydration shells of HSA (i.e., mainly SBW) and in the solution (i.e., WBW+non-bound bulk water).

A novel 3D Ag(I)-MOF: Surfactant-directed syntheses and catalytic degradation of o/m/p-Nitrophenol

For the first time, sodium caprylate has been investigated to direct the crystal growth of 3D Ag-MOF, [Ag2(ddcba)(4,4′-bipy)2] (1), constructing from 3,5-(di(2′,5′-dicarboxylphenyl)benozoic acid and 4,4′-bipy. The single crystal diffraction analyses shows that complex 1 possess 3D neutral framework with a three-connected ThSi2 (103-b) topology. Compound 1 exhibits predominant catalytic activity towards the degradation of o-Nitrophenol (ONP), m-Nitrophenol (MNP) and p-Nitrophenol (PNP) in aqueous solution. The kinetics of such catalytic degradation reactions was also studied.

A Novel Suspension Formulation Enhances Intestinal Absorption of Macromolecules Via Transient and Reversible Transport Mechanisms

PurposeMedium chain fatty acid salts promote absorption by increasing paracellular permeability of the intestinal epithelium. Novel oily suspension (OS) formulation disperses a powder containing sodium caprylate and macromolecules such as octreotide or fluorescent dextran (FD). Formulation safety, macromolecule absorption and pharmacokinetic (PK)/pharmacodynamic (PD) were evaluated.MethodsOctreotide/OS toxicity was evaluated in monkeys following 9 months of daily oral enteric-coated capsule administration. The OS permeation effect was also assessed in rats, using FD/OS and octreotide/OS preparations. Octreotide/OS effects on circulating growth hormone (GH) levels were also measured.ResultsSafety assessment of octreotide/OS in monkeys after 9 months showed minor drug-related findings, comparable to the injectable octreotide. Octreotide exposure levels were similar across the treatment periods. In rats, OS facilitated FD permeation up to 70 kDa in a reversible, spatial and dose-dependent manner, independent of the intestinal dosing site. Following OS administration, the staining pattern of the tight-junction protein, ZO-1, changed transiently, and a paracellular penetration marker, LC-biotin, permeated between adjacent epithelial cells. Enteral octreotide/OS absorption was dose-dependent and suppressed rat GH levels.ConclusionsOral octreotide/OS dosing was shown to be safe in monkeys. OS enhances intestinal absorption of active octreotide, likely by transient alteration of the tight junction protein complex.

The Role of Caprylate Ligand Ion on the Stabilization of Human Serum Albumin

Sodium caprylate was added to a pharmaceutical-grade human serum albumin (HSA) to stabilize the product. In this study we have aimed to establish how caprylate ligand protects HSA from thermal degradation. The fatty acid stabilizer was first removed from commercial HSA by charcoal treatment. Cleaned HSA was made to 10% w/v in pH 7.4 buffered solutions and doped with sodium caprylate in serial concentrations up to 0.16 mmol/g-protein. These solutions as well as a commercial HSA, human serum, and enriched-albumin fraction were subjected to differential scanning calorimetry (DSC) within the temperature range of 37-90°C at a 5.0°C/min scanning rate. The globular size of the cleaned HSA solutions was measured by dynamic light scattering. The denaturing temperatures for albumin with sodium caprylate and a commercial one were significantly higher than for albumin only. It was found that the protein globules of cleaned HSA were not as stable as that of the native one due to aggregation, and the caprylate ion may reduce the aggregation by enlarging the globules' electrical double layer. A rational approximation of the Lumry-Eyring protein denaturation model was used to treat DSC denaturing endotherms. The system turned from irreversible dominant Scheme: N (k3K)→ P to reversible dominant Scheme:N (k1)→ P with the increase in caprylate concentration from null to ~0.08 mmol/g-protein. It was postulated that the caprylate ligand may decrease the rate of reversible unfolding as it binds to the IIIA domain which is prone to reversible unfolding/refolding and causes further difficulty for irreversible denaturation which, in turn, HSA can be stabilized.

Caprylate as the albumin-selective modifier to improve IgG purification with hydrophobic charge-induction chromatography

Hydrophobic charge-induction chromatography (HCIC) is a novel downstream bioprocessing technology for antibody purification and it has several advantages over traditional purification processes. However, its separation selectivity still needs to be improved. In this work, sodium caprylate (NaCA) was used as the selective modifier to improve IgG purification from serum albumin containing feedstock with a typical HCIC resin, MEP HyperCel. The effects of NaCA on the adsorption equilibrium of bovine serum immunoglobulin G (IgG) and bovine serum albumin (BSA), as well as the dynamic binding and displacement behaviors were investigated. The binding and elution behaviors of these two proteins in the column were studied. It was found that adding 50–75mM NaCA in the liquid phase could effectively reduce the adsorption of BSA on the MEP resin, but the same treatment has little influence on the adsorption of IgG. Moreover, the mechanism of the competitive binding between caprylate and MEP ligands on the surface of BSA is discussed. It was found that by controlling NaCA addition in the loading or washing buffer, the process efficiency of IgG purification from BSA containing feedstock can be improved, and the purity of IgG could reach to over 98%. The results indicated that caprylate could be a promising albumin-selective modifier to improve the separation efficiency of antibodies with the HCIC process.

Preparation of Calix[4]arene Alkylamine Derivatives by Mannich Reaction and use as Phase-Transfer Catalysts for Esterification Reaction

In this study, 5,11,17,23-tetrakis[(N-ethylpiperazine)methyl]-25,26,27,28-tetrahydroxycalix[4]arene (3) and 5,11,17,23-tetrakis[(4-carboethoxy-N-piperidino) methyl]-25,26,27,28-tetrahydroxycalix[4]arene (4) were synthesized in one step according to the Mannich reaction by the treatment of calix[4]arene with a secondary amine (N-ethylpiperazine, ethyl-4-piperidincarboxylate) and formaldehyde. The calix[4]arene derivatives (3, 4) were characterized by a combination of FTIR, 1H NMR and elemental analyses. The synthesized compounds were used in an esterification reaction as the phase transfer catalyst. The catalytic efficiency of the calix[4]arenes 3 and 4 was evaluated by carrying out the ester-forming reaction of alkali metal carboxylates (sodium butyrate or sodium caprylate) with p-nitrobenzyl bromide. It was observed that the ester-forming reaction of alkali metal carboxylates with p-nitrobenzyl bromide, using calix[4]arene-based catalyst 3 as a phase-transfer catalyst in dichloromethan, provided the best yields.