Gamma irradiating chromatography columns enables bioburden-free integrated continuous biomanufacturing

An important consideration for integrated continuous biomanufacturing is that the downstream chromatography steps integrated with the bioreactor should maintain a low bioburden state throughout the entire duration of the operation. One potential strategy to achieve this is to start bioburden-free and functionally close the chromatography system. While chromatography skids themselves can be rendered bioburden-free, limitations exist in applying these methods to chromatography columns. The small column sizes used in continuous multicolumn chromatography enable gamma irradiation of disposable columns to render them bioburden-free. However, this approach has not been widely implemented, likely because gamma irradiation can negatively impact resin performance. Here, several protective mobile-phase modifiers were screened and shown to help chromatography resins retain naïve-like performance. Gamma irradiated columns were then integrated into perfusion bioreactors for continuous capture. Successful integrated continuous capture downstream of perfusion bioreactors for greater than 40 days using protein A, custom affinity, and non-affinity capture resins for multiple biologic modalities is demonstrated in development and commercial settings. No indications of time-based performance decline or bioburden growth have been observed. This strategy enables bioburden-free integrated continuous biomanufacturing operations and could allow full process closure and decreased environmental control requirements for facilities; thus, permitting simultaneous multi-product operations in a ballroom arrangement.

Are deep eutectic solvents useful in chromatography? A short review

A literature update has been done concerning Deep Eutectic Solvents (DES) use in chromatography applications. The literature survey was based on the period from 2010 till 2020 and manuscripts reported in the data bases Web of Science and Scopus. The use of DES as mobile phase and mobile phase additives, stationary phases and solid phase modifiers and the use of DES as reaction solvents for chromatography use, were evaluated. Emphasis was placed on the differentiation of DES and Ionic Liquids (ILs) and the advanced green characteristics of the new solvents as compared with traditional organic solvents and ILs with a look into the drawbacks and future perspectives in the field of separation methods.

Extending the Depth of Human Plasma Proteome Coverage Using Simple Fractionation Techniques

Human plasma is one of the most widely used tissues in clinical analysis, and plasma-based biomarkers are used for monitoring patient health status and/or response to medical treatment to avoid unnecessary invasive biopsy. Data-driven plasma proteomics has suffered from a lack of throughput and detection sensitivity, largely due to the complexity of the plasma proteome and in particular the enormous quantitative dynamic range, estimated to be between 9 and 13 orders of magnitude between the lowest and the highest abundance protein. A major challenge is to identify workflows that can achieve depth of plasma proteome coverage while minimizing the complexity of the sample workup and maximizing the sample throughput. In this study, we have performed intensive depletion of high-abundant plasma proteins or enrichment of low-abundant proteins using the Agilent multiple affinity removal liquid chromatography (LC) column-Human 6 (Hu6), the Agilent multiple affinity removal LC column-Human 14 (Hu14), and ProteoMiner followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS PAGE) and C18 prefractionation techniques. We compared the performance of each of these fractionation approaches to identify the method that satisfies requirements for analysis of clinical samples and to include good plasma proteome coverage in combination with reasonable sample output. In this study, we report that one-dimensional (1D) gel-based prefractionation allows parallel sample processing and no loss of proteome coverage, compared with serial chromatographic separation, and significantly accelerates analysis time, particularly important for large clinical projects. Furthermore, we show that a variety of methodologies can achieve similarly high plasma proteome coverage, allowing flexibility in method selection based on project-specific needs. These considerations are important in the effort to accelerate plasma proteomics research so as to provide efficient, reliable, and accurate diagnoses, population-based health screening, clinical research studies, and other clinical work.

Achiral Molecular Recognition of Substituted Aniline Position Isomers by Crown Ether Type Chiral Stationary Phase

To understand the selectivity of the crown ether type chiral stationary phase (CSP), the retention selectivity for aniline and the positional isomers of substituted anilines were studied. In various substituted isomers, except nitroaniline, a remarkable decrease of retention due to steric hindrance was observed for the 2-substituted isomer. To determine the detailed molecular recognition mechanism, quantum chemical calculations were performed for the aggregates between the crown ether and the anilines. The results suggested that the 20-Crown-6, which includes a phenyl-substituted 1,1'-binaphthyl moiety, interacts with alkyl and aryl amines in an unconventional form different from the proposed one for 18-Crown-6.

Progress in the Enantioseparation of β-Blockers by Chromatographic Methods

β-adrenergic antagonists (β-blockers) with at least one chiral center are an exceedingly important class of drugs used mostly to treat cardiovascular diseases. At least 70 β-blockers have been investigated in history. However, only a few β-blockers, e.g., timolol, are clinically marketed as an optically pure enantiomer. Therefore, the separation of racemates of β-blockers is essential both in the laboratory and industry. Many approaches have been explored to obtain the single enantiomeric β-blocker, including high performance liquid chromatography, supercritical fluid chromatography and simulated moving bed chromatography. In this article, a review is presented on different chromatographic methods applied for the enantioseparation of β-blockers, covering high performance liquid chromatography (HPLC), supercritical fluid chromatography (SFC) and simulated moving bed chromatography (SMB).

Engineered Bacterial Production of Volatile Methyl Salicylate

The engineering of microbial metabolic pathways over the last two decades has led to numerous examples of cell factories used for the production of small molecules. These molecules have an array of utility in commercial industries and as in situ expressed biomarkers or therapeutics in microbial applications. While most efforts have focused on the production of molecules in the liquid phase, there has been increasing interest in harnessing microbes' inherent ability to generate volatile compounds. Here, we optimized and characterized the production of methyl salicylate, an aromatic compound found mainly in plants, using a common lab strain of E. coli. We utilized genetic components from both microbes and plants to construct the volatile metabolite circuit cassette. In order to maximize production, we explored expression of methyl salicylate precursors, upregulation of expression by increasing ribosomal binding strength and codon optimization of the methyl transferase gene obtained from plant Petunia x hybrida. Last, we validated and quantified the production of methyl salicylate with liquid chromatography or gas chromatography mass spectrometry (LC-MS or GC-MS) and found that the codon optimized strain with precursor supplementation yielded the highest production compared to the other strains. This work characterizes an optimized metabolite producing genetic circuit and sets the stage for creation of an engineered bacteria diagnostic to be used in volatile assays.

Correlation between enzyme multiplied immunoassay technique and high-performance liquid chromatography in the quantification of voriconazole in a paediatric population

The enzyme multiplied immunoassay technique (EMIT) is a new method for determining the plasma concentration of voriconazole (VRZ). This study aimed to investigate the correlation between EMIT and high-performance liquid chromatography/ultraviolet rays (HPLC/UV) in determining the plasma VRZ trough concentration in children, in China. A total of 419 blood samples were collected, and plasma VRZ concentrations were detected by the EMIT and HPLC methods. The results of 304 samples were analysed after excluding samples that were undetectable or beyond the quantification limit. A test result value of 0 was defined as undetectable, while concentrations outside the detection range (0.2 - 20.0 μg/ml for HPLC and 0.5 - 16.0 µg/ml for EMIT) were defined as beyond the quantification limit. Results from both methods were compared using the Passing Bablok regression, Bland-Altman plot analysis, and paired Wilcoxon test. The plasma VRZ concentrations determined by EMIT and HPLC showed a strong linear correlation through the linear regression equation Y_EMIT = 1.310 × HPLC +0.149 (R² = 0.9082). The Bland-Altman plot analysis showed poor level consistency as measured by the two methods. The paired Wilcoxon-test showed a significant difference between the two methods (p < .0001). Compared to EMIT, HPLC accurately detected plasma VRZ concentration, making it suitable for VRZ therapeutic drug monitoring. The numerical values of the EMIT-measured levels were higher than those of HPLC, which may be related to VRZ metabolites interference and co-administrated drugs.

Mechanistic insights into viral clearance during the chromatography steps in antibody processes by using virus surrogates

Viral safety is required for biological products to treat human diseases, and the burden of inactivation and or virus removal lies on the downstream purification process. Minute virus of mice (MVM) is a nonenveloped parvovirus commonly used as the worst-case model virus in validation studies because of its small size and high chemical stability. In this study, we investigated the use of MVM-mock virus particle (MVP) and bacteriophage ΦX174 as surrogates for MVM to mimic viral clearance studies, with a focus on chromatography operations. Based on structural models and comparison of log reduction value among MVM, MVP, and ΦX174, it was demonstrated that MVP can be used as a noninfectious surrogate to assess viral clearance during process development in multiple chromatography systems in a biosafety level one (BSL-1) laboratory. Protein A (ProA) chromatography was investigated to strategically assess the impact of the resin, impurities, and the monoclonal antibody product on virus removal.

Robustness and Ruggedness of Isoelectric Focusing and Superficially Porous Liquid Chromatography with Fourier Transform Mass Spectrometry

An investigation of a multidimensional proteomics workflow composed of off-gel isoelectric focusing (IEF) and superficially porous liquid chromatography (SPLC) with Fourier transform mass spectrometry (FTMS) was completed in order to assess various figures of merit associated with intact protein measurements. Triplicate analysis performed at both high and low FTMS resolutions on the E. coli proteome resulted in ∼900 redundant proteoforms from 3 to 95 kDa. Normalization of the chromatographic axis to identified proteoforms enabled reproducible physicochemical property measurements between proteome replicates with inter-replicate variances of ±3 ppm mass error for proteoforms <30 kDa, ±1.1 Da for proteins >30 kDa, ±12 s retention time error, and ±0.21 pI units. The results for E. coli and standard proteins revealed a correlation between pI precision and proteoform abundance with species detected in multiple IEF fractions exhibiting pI precisions less than the theoretical resolution of the off-gel system (±0.05 vs ±0.17, respectively). Evaluation of differentially modified proteoforms of standard proteins revealed that high sample loads (100s μgrams) change the IEF pH gradient profile, leading to sample broadening that facilitates resolution of charged post-translational modifications (e.g., phosphorylation, sialylation). Despite the impact of sample load on IEF resolution, results on standard proteins measured directly or after being spiked into E. coli demonstrated that the reproducibility of the workflow permitted recombination of the MS signal across IEF fractions in a manner supporting the evaluation of three label-free quantitation metrics for intact protein studies (proteoforms, proteoform ratios, and protein) over 102-103 sample amount with low femtomole detection limits.

Bioanalytical methodologies for clinical investigation of endocrine-disrupting chemicals: a comprehensive update

Endocrine-disrupting chemicals (EDCs) are xenobiotics that disrupt the endocrine system in humans at ecologically significant concentrations. Various substances are exposed to human health via routes including food, water, air and skin that result in disastrous maladies at low doses as well. Therefore EDCs need a meticulous strategy of analysis for dependable and consistent monitoring in humans. The management and risk assessment necessitate advancements in the detection methodologies of EDCs. Hyphenated MS-based chromatograph and other validated laboratory analysis methods are widely available and employed. Besides, in vitro bioassay techniques and biosensors are also used to conduct accurate toxicological tests. This article provides a revision of various bioanalytical detection methods and technologies for the clinical estimation of EDCs.

Dataset from HDX-MS Studies of IgG1 Glycoforms and Their Interactions with the FcγRIa (CD64) Receptor

This document presents hydrogen-deuterium exchange mass spectrometry (HDX-MS) data from measurements of three purified IgG1 glycoform samples, predominantly G0F, G2F, and SAF, in isolation and in complexation with the high-affinity receptor, FcγRIa (CD64). The IgG1 antibody used in this study, aIL8hFc, is a murine-human chimeric IgG1, which inhibits IL-8 binding to human neutrophils.

Determination of in vitro human whole blood-to-plasma ratio of THJ-018 utilizing gas chromatography-Mass spectrometry

OBJECTIVES

This study was aimed to determine in vitro human whole blood-to-plasma ratio (KWB/P) of THJ-018 by gas chromatography/mass spectrometry (GC/MS).

MATERIALS AND METHODS

The samples (human blood) were sprayed with THJ-018 and an internal standard and extracted using solid-phase extraction. THJ-018 was determined in the final extracts by GC/MS.

RESULTS

The value for KWB/P was 1.56 (1.38-1.81), and red blood cell partitioning was 1.01 (1.01-1.02). The distribution of THJ-018 between whole blood and plasma was observed to be affected by temperature.

CONCLUSION

The data analysis supports the proposition that the ratio of the plasma to whole blood concentrations (1.56) is a suitable parameter characterizing THJ-018 distribution in whole blood. For toxicological analysis, it would be best to refrain from converting any drug concentration measured in whole blood to that anticipated in plasma or serum; however, toxic and therapeutic concentrations should be determined for the individual specimens collected.

Advances in the Detection of Dithiocarbamate Fungicides: Opportunities for Biosensors

Dithiocarbamate fungicides (DTFs) are widely used to control various fungal diseases in crops and ornamental plants. Maximum residual limits in the order of ppb-ppm are currently imposed by legislation to prevent toxicity problems associated with excessive use of DTFs. The specific analytical determination of DTFs is complicated by their low solubility in water and organic solvents. This review summarizes the current analytical procedures used for the analysis of DTF, including chromatography, spectroscopy, and sensor-based methods and discusses the challenges related to selectivity, sensitivity, and sample preparation. Biosensors based on enzymatic inhibition demonstrated potential as analytical tools for DTFs and warrant further research, considering novel enzymes from extremophilic sources. Meanwhile, Raman spectroscopy and various sensors appear very promising, provided the selectivity issues are solved.

Low-Cost Benzene Toluene Xylene Measurement Gas System Based on the Mini Chromatographic Cartridge

Benzene, toluene and xylene (BTX) are an important part of the volatile organic compounds (VOCs) to be detected and monitored in the air, due to their toxicity towards human health. One of the most reliable technique used in BTX detection is gas chromatography (GC), which presents a high sensitivity. On the other hand, it has important drawbacks, such as high costs, the need for qualified personnel and frequent maintenance. To overcome these drawbacks, this work reports the development of a low cost and portable BTX gas detection system based on a mini chromatographic cartridge, a photo ionization detector (PID), a simple control unit (based on Arduino architecture) and a mini pump. In order to separate the BTX components, we propose the use of a cartridge 80 mm in length, composed of several commercial chromatographic column sections. To test the system performances, we have injected different amounts (from about 0.3 to 5.3 µg) of benzene, toluene and xylene and two of the most frequent possible interferents (ethanol, acetone). Experimental results have shown different retention time values (i.e., 25 ± 0.5 s, 51 ± 1.2 s and 117 ± 4 s, respectively) for benzene, toluene and xylene.

Measurement of Serum Testosterone in Nondiabetic Young Obese Men: Comparison of Direct Immunoassay to Liquid Chromatography-Tandem Mass Spectrometry

Hypoandrogenemia, a frequent finding in men with obesity, is defined by low concentrations of serum testosterone. Although immunoassay (IA) is the most used method for the determination of this steroid in clinical practice, liquid chromatography-mass spectrometry (LC-MS/MS) is considered a more reliable method. In this study, we aimed to compare IA versus LC-MS/MS measurement for the diagnosis of hypoandrogenemia in a cohort of 273 nondiabetic young obese men. Mean total testosterone (TT) levels were 3.20 ± 1.24 ng/mL for IA and 3.78 ± 1.4 ng/mL for LC-MS/MS. 53.7% and 26.3% of patients were classified as presenting hypoandrogenemia with IA and LC-MS/MS, respectively. Considering LC-MS/MS as the reference method, sensitivity and specificity of IA were 91.4% (95% CI 82.3-96.8) and 61.1% (95% CI 54.0-67.8), respectively. IA presented an AUC of 0.879 (95% CI 0.83-0.928). Multivariate regression analysis indicated that sex hormone-binding globulin (SHBG) concentrations (p = 0.002) and insulin resistance (p = 0.008) were factors associated with discrepant IA values. In conclusion, the determination of TT by IA in nondiabetic young men with obesity yields lower concentrations of TT than LC-MS/MS, resulting in an equivocal increased diagnosis of hypoandrogenemia, which could lead to inaccurate diagnosis and unnecessary treatment.

Data-Independent Acquisition for the Quantification and Identification of Metabolites in Plasma

A popular fragmentation technique for non-targeted analysis is called data-independent acquisition (DIA), because it provides fragmentation data for all analytes in a specific mass range. In this work, we demonstrated the strengths and weaknesses of DIA. Two types of chromatography (fractionation/3 min and hydrophilic interaction liquid chromatography (HILIC)/18 min) and three DIA protocols (variable sequential window acquisition of all theoretical mass spectra (SWATH), fixed SWATH and MS^ALL) were used to evaluate the performance of DIA. Our results show that fast chromatography and MS^ALL often results in product ion overlap and complex MS/MS spectra, which reduces the quantitative and qualitative power of these DIA protocols. The combination of SWATH and HILIC allowed for the correct identification of 20 metabolites using the NIST library. After SWATH window customization (i.e., variable SWATH), we were able to quantify ten structural isomers with a mean accuracy of 103% (91-113%). The robustness of the variable SWATH and HILIC method was demonstrated by the accurate quantification of these structural isomers in 10 highly diverse blood samples. Since the combination of variable SWATH and HILIC results in good quantitative and qualitative fragmentation data, it is promising for both targeted and untargeted platforms. This should decrease the number of platforms needed in metabolomics and increase the value of a single analysis.

Chemometrics-based models hyphenated with ensemble machine learning for retention time simulation of isoquercitrin in Coriander sativum L. using high-performance liquid chromatography

In this research, two nonlinear models, namely; adaptive neuro-fuzzy inference system and feed-forward neural network and a classical linear model were employed for the prediction of retention time of isoquercitrin in Coriander sativum L. using the high-performance liquid chromatography technique. The prediction employed the use of composition of mobile phase and pH as the corresponding input parameters. The performance indices of the models were evaluated using root mean square error, determination co-efficient, and correlation co-efficient. The results obtained from the simple models showed that subclustering-adaptive-neuro fuzzy inference system gave the best results in both the training and testing phases and boosted the performance accuracy of the simple models. The overall comparison of the results showed that subclustering-adaptive-neuro fuzzy inference system ensemble demonstrated outstanding performance and increased the accuracy of the single models and ensemble models in the testing phase, up to 35% and 3%, respectively.

A Critical Review on Analytical Methods for Recently Approved FDC Drugs: Pregabalin and Etoricoxib

Fixed-dose combinations (FDCs) refer to products containing two or more active ingredients combined in a single dosage form. The FDCs are justified because of several advantages. These are a) potentiating therapeutic efficacy, b) reducing the incidences of adverse drug effects, c) having pharmacokinetic advantages, d) reducing pills burden, e) reducing the dose of individual drugs and f) decreasing the drug resistance development. A recently approved FDC of Pregabalin IP (75 mg) and Etoricoxib (60 mg) recommended to control neuropathic chronic back pain. Analytical methods are available for individual quantitation of pregabalin (PGB) and etoricoxib (ETC), but an effective and reliable analytical method has not been reported for their combination. Thus, the objective of this literature survey was to gather information on various analytical instrumental methods used so far for the individual quantitation of PGB and ETC in various matrices. Such data would be useful to the scientific community to develop a novel analytical method for the analysis of recently approved FDC of PGB and ETC. Various scientific databases were explored to meet the objectives, and the information is synchronized. The reported methods are high-performance liquid chromatography (48% & 53%), hyphenated techniques (54% & 21%), spectroscopy (50% & 34%), and high-performance thin-layer chromatography, or thin-layer chromatography (6% & 13%) for pregabalin and etoricoxib, respectively. All these methods were specific and selective for the analysis of individual drugs.

Quality control, HPTLC analysis, antioxidant and antimicrobial activity of hydroalcoholic extract of roots of qust (Saussurea lappa, C.B Clarke)

OBJECTIVES

Saussurea lappa, CB Clarke (S.lappa) is a perennial herb of the Compositae family. The root of S.lappa has been used for the treatment of various diseases such as hepatitis, jaundice, intestinal worms, bronchial asthma, and a variety of skin diseases. The aim of the study was to ensure quality control of S.lappa and its preparation HAESL (hydroalcoholic extract of S.lappa) along with assessment of HAESL antimicrobial and antioxidant activities in vitro.

METHODS

HAESL was prepared with 50% ethanol, (v/v). Physiochemical analysis of the root of S.lappa, and phytochemical screening, thin-layer chromatography (TLC), high-performance thin-layer chromatography (HPTLC), and in vitro antimicrobial and antioxidant activity of HAESL were performed using the standard protocol.

RESULTS

Physiochemical and phytochemical assessments of S.lappa and HAESL showed the greater quality of the drug. HAESL showed the presence of many phytochemical constituents corresponding to colorful spots, peaks, area under the curve, and corresponding Rf values as evident in the TLC and HPTLC analysis. HAESL showed a concentration-dependent effect on radical scavenging activity against DPHH (2,2-diphenyl-1-picrylhydrazyl) and hydroxyl radical with IC50 value of 19.10 μg/mL and 82.23 μg/mL, respectively. HAESL exhibited antimicrobial activity against the growth of micro-organisms such as Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, Aspergillus flavus, and Candida albicans. HASEL showed no antimicrobial activity against Aspergillus niger.

CONCLUSIONS

The procured and an identified sample of Saussurea lappa was good in quality and the prepared HAESL contained many phytochemical compounds. HAESL substantiated significant antioxidant and antimicrobial activity in vitro.

Advances in Lentivirus Purification

Lentiviral vectors (LVs) have been increasingly used as a tool for gene and cell therapies since they can stably integrate the genome in dividing and nondividing cells. LV production and purification processes have evolved substantially over the last decades. However, the increasing demands for higher quantities with more restrictive purity requirements are stimulating the development of novel materials and strategies to supply the market with LV in a cost-effective manner. A detailed review of each downstream process unit operation is performed, limitations, strengths, and potential outcomes being covered. Currently, the majority of large-scale LV manufacturing processes are still based on adherent cell culture, although it is known that the industry is migrating fast to suspension cultures. Regarding the purification strategy, it consists of batch chromatography and membrane technology. Nevertheless, new solutions are being created to improve the current production schemes and expand its clinical use.

The chromatographic behaviour of new double-labelled oligodeoxynucleotide probes containing azaphthalocyanine dye as a quencher with respect to evaluation of their purity

The influence of experimental conditions on chromatographic behaviour of promising oligodeoxynucleotide double-labelled molecular probes containing an azaphthalocyanine macrocycle as a perspective dark quencher was studied. A recently introduced new stationary phase based on styrene-divinylbenzene copolymer was tested. The planar and hydrophobic structure of the azaphthalocyanine is considerably different from those of currently used fluorophores and quenchers. Thus, the most challenging issue was the separation of the double-labelled probe from its main impurity represented by a mono-labelled probe, containing only the azaphthalocyanine macrocycle. The absorbance measurement cannot simply determine this impurity, and its presence fundamentally compromises the biological assay. The commonly used gradient elution was not suitable and isocratic conditions seemed to be more appropriate. The azaphthalocyanine moiety influences the properties of the modified oligodeoxynucleotides substantially, and thus their chromatographic behaviour was determined predominantly by this quencher. Acetonitrile was the preferred organic solvent for the analysis of probes containing the azaphthalocyanine quencher and the effect of ion-pairing reagents was dependent on the probe structure. The temperature seemed to be an effective parameter for fine-tuning of the separation and mass transfer improvement. Generally, our findings could be helpful in method development for purity evaluation of double-labelled oligodeoxynucleotide probes and semipreparative methods.

Application of Heparin Affinity Chromatography to Produce a Differential Vaccine without Eliciting Antibodies against the Nonstructural Proteins of the Serotype O Foot-and-Mouth Disease Viruses

Although polyethylene glycol (PEG) application is the most widely used method in removing nonstructural proteins (NSPs) for foot-and-mouth disease (FMD) vaccine production, some NSPs remaining in the antigen could elicit antibodies against these proteins after repeated vaccinations in livestock. Therefore, the purpose of this study was to purify the FMD virus (FMDV) via affinity chromatography using a heparin ligand to remove most proteins, including NSPs. Chromatography showed an intact virus (146S) particle recovery of 70% or more for three different strains of serotype O FMDV (two locally isolated strains and one genetically modified strain). The experimental vaccine made with antigens eluted via heparin affinity chromatography elicited virus-neutralizing antibodies against homologous viruses but did not induce antibodies against NSPs even after five immunizations in goats; this indicated that the NSPs were effectively removed from the vaccine antigen. This method can then be used to produce a higher-quality vaccine compared with PEG application in terms of the purity of the FMD vaccine. Therefore, this result would be an important groundwork for advanced FMD vaccine manufacturing in the near future.

Lead removal by ThioOctolig

Octolig, a commercially available (a polyethylene diamine covalently attached to silica gel), was subjected to modifications to incorporate sulfur for enhanced removal of lead ion from aqueous solutions. The basic approach was attempted formation of "ThioOctolig" by the reaction of Octolig with thioacetamide in toluene using a shaker bath for 24 or 48 h or in the presence of 10% HCl (1 h). Our experience was that conversion was limited to about 20% based on sulfur analysis for 24 or 48 h reaction time, or in the presence of 10% HCl. In fact, with acidification, the results were poorer. Duplicate runs indicated consistent results. Literature reported that SbCl₃ was an effective catalyst with a reaction time of 1 h. Use of this reagent (1-h reaction time) produced a bright orange red product, in contrast with previous yellow-colored products. A control run indicated that this reagent reacted with Octolig in toluene (in the dark) to produce a red-colored sample; thioacetamide reacted to produce a yellow sample. Use of SbCl₃ (∼5 mole %) did not enhance the sulfur content of Octolig. A sample of Octolig removed 68% lead ion from a 120 ppm aqueous lead while a sample of ThioOctolig (10% S) removed 99.4% lead ions. We also investigated enhancing the sulfur incorporation upon raising the reaction temperature with thioacetamide.

Evaluation of tea tree oil physicochemical features and its antimicrobial activity against Cutibacterium acnes (Propionibacterium acnes) ATCC 6919

Introducción.

El aceite del árbol de té es un aceite esencial reconocido por sus propiedades antimicrobianas.

Objetivos.

Evaluar la composición, características y efecto antimicrobiano del aceite al 2 % del árbol de té y su concentración inhibitoria mínima (CIM) contra Cutibacterium acnes (Propionibacterium acnes).

Materiales y métodos.

Se evaluó el quimiotipo en tres lotes diferentes de este aceite mediante cromatografía de gases, así como su actividad antimicrobiana en concentración al 2 % v/v y la CIM contra C. acnes mediante ensayo de difusión en agar (guía M11-A8 CLSI).

Resultados.

Los lotes evaluados presentaron los quimiotipos ajustados a la norma ISO 4730, lo que indicó la alta calidad del producto. Los lotes contenían de 30 a 40 % de terpinen-4-ol, compuesto que favorece la actividad antimicrobiana, la cual presentó en todos los lotes un efecto dependiente de la concentración contra C. acnes, con una inhibición del crecimiento microbiano en concentración al 2 % v/v en todas las pruebas. La concentración inhibitoria mínima fue de 0,25 % v/v. La actividad antimicrobiana del aceite del árbol de té contra este microorganismo ya ha sido reportada con una concentración inhibitoria mínima entre 0,05 y 1,25 % v/v, rango que cobija la obtenida en este estudio.

Conclusiones.

Los resultados evidenciaron la gran calidad de este producto y su capacidad como agente antibacteriano contra C. acnes. Se deben hacer estudios con otros aislamientos del microorganismo provenientes de pacientes con acné vulgar para confirmar su actividad general y la de cada uno de sus componentes.

Preparation and characterisation of magnetosomes based drug conjugates for cancer therapy

The authors report a novel, effective and enhanced method of conjugating anticancer drug, paclitaxel and gallic acid with magnetosomes. Here, anticancer drugs were functionalised with magnetosomes membrane by direct and indirect (via crosslinkers: glutaraldehyde and 3-aminopropyltriethoxysilane) adsorption methods. The prepared magnetosome-drug conjugates were characterised by Fourier transform infrared, zeta potential, field-emission scanning electron microscope and thermogravimetric analysis/differential scanning calorimetry. The drug-loading efficiency and capacity were found to be 87.874% for paclitaxel (MP) and 71.3% for gallic acid (MG), respectively as calculated by ultraviolet spectroscopy and high-performance liquid chromatography. The drug release demonstrated by the diffusion method in phosphate buffer (PBS), showing a prolonged drug release for MP and MG, respectively. The cytotoxicity effect of the MP and MG displayed cytotoxicity of 69.71%, 55.194% against HeLa and MCF-7 cell lines, respectively. The reactive oxygen species, acridine orange and ethidium bromide and 4, 6-diamidino-2-phenylindole staining of the drug conjugates revealed the apoptotic effect of MP and MG. Further, the regulation of tumour suppressor protein, p53 was determined by western blotting which showed an upregulation of p53. Comparatively, the magnetosome-drug conjugates prepared by direct adsorption achieved the best effects on the drug-loading efficiency and the increased percentage of cancer cell mortality and the upregulation of P53. The proposed research ascertains that magnetosomes could be used as effective nanocarriers in cancer therapy.