Inclusion Of Organic Solvents Research Articles

Obtaining a Water-soluble Form of Hydrophobic Indolelocarbazole Derivative Using Solubilizer Complex

Introduction. LHS-1269 is an indolocarbazole derivative with high antitumor activity. Due to the hydrophobic properties of the active substance, the use of organic co-solvents – dimethyl sulfoxide (DMSO) and ethanol – is required to obtain an injectable dosage form (DP). However, the inclusion of organic solvents in the composition of the DF carries a potential risk of side effects as a result of the use of the drug.Aim. Selection of auxiliary substances for obtaining an aqueous solution of hydrophobic indolecarbazole derivative, which allows minimizing the concentration of organic solvents in the composition of DF.Materials and methods. The object of the study is the active substance LHS-1269 series 010320, produced in the Chemical Synthesis Laboratory of the N. N. Blokhin National Medical Research Center of Oncology. The following auxiliary substances were used to obtain model compositions: Kollidon® 17 PF, Kollisolv® PEG-400, Kolliphor® P 188, Montanox™ 20, DMSO (p.a.), ethanol 95 % (standardized according to pharmacopoeia quality standard ФС.2.2.0019.18 of The State Pharmacopoeia of the Russian Federation). Analytical scales OHAUS Analytical Plus AP 100S and laboratory scales AND DL-120 were used for weighing LHS-1269 and auxiliary substances. The dissolution and mixing of the components was carried out on an IKA® C-MAG HS 4 magnetic stirrer.Results and discussion. In the course of the study, 2 groups of model compositions were obtained and estimated, comprising a complex of two or more auxiliary substances as a solubilizer. The first group of formulations contained DMSO at a concentration of 5 % and ethanol at concentrations from 0 to 15 %. The compositions of the second group included DMSO from 0 to 4 %. As a result, it was found that the addition of 5 % Kolliphor® P 188 to the composition of the solution reduces the content of ethanol to 5 %. In this case, with further decrease in ethanol, turbidity of the solution and precipitation are observed. Reducing the concentration of DMSO in the DF to 2 % was achieved by using a combination of 20 % ethanol and solubilizer complex – Kollidon® 17 (20 %), Kollisolv® PEG-400 (20 %) and Kolliphor® P 188 (5 %). In this case, the total dissolution of the active substance without DMSO was observed when compensating for the organic solvent by introducing additional auxiliary substances – Montanox™ 20 (5 %) and benzene (2 %).Conclusion. As a result of the research, the compositions of the auxiliary substances of solubilizers are selected, allowing to obtain an aqueous solution of the hydrophobic compound LHS-1269 with a minimum concentration of organic solvents.

Functional Nucleic Acids Under Unusual Conditions.

Functional nucleic acids (FNAs), including naturally occurring ribozymes and riboswitches as well as artificially created DNAzymes and aptamers, have been popular molecular toolboxes for diverse applications. Given the high chemical stability of nucleic acids and their ability to fold into diverse sequence-dependent structures, FNAs are suggested to be highly functional under unusual reaction conditions. This review will examine the progress of research on FNAs under conditions of low pH, high temperature, freezing conditions, and the inclusion of organic solvents and denaturants that are known to disrupt nucleic acid structures. The FNA species to be discussed include ribozymes, riboswitches, G-quadruplex-based peroxidase mimicking DNAzymes, RNA-cleaving DNAzymes, and aptamers. Research within this space has not only revealed the hidden talents of FNAs but has also laid important groundwork for pursuing these intriguing functional macromolecules for unique applications.

Guest-Dependent Dynamics in a 3D Covalent Organic Framework

Guest-dependent dynamics having both crystal contraction and expansion upon inclusion of various guests is uncovered in a 3D covalent organic framework (COF) prepared with a facile and scalable method. A molecular-level understanding of how the framework adjusts thenode geometry and molecular configuration to perform significant contraction and large amplitude expansion are resolved through synchrotron in-house powder X-ray diffraction (PXRD) and Rietveld refinements. We found that the COF adopts a contracted phase at ambient conditions upon capturing moisture and is also adaptive upon inclusion of organic solvents, which is highlighted by a large crystal expansion (as large as 50% crystallographic volume increment and a 3-fold channel size enlargement). With this new knowledge of the structural adaptability, the diverse responses and coherent switchability are thereby presented to pave the way to rational design and deliberate control ofdynamic COFs.

Abstract 942: Sensitive detection of microsatellite instability (MSI) in tumors and liquid biopsies using nuclease-based enrichment

Abstract The role of MSI in colorectal cancer (CRC) is well characterized, and colon tumors are classified as MSI-High or MSI-Stable by screening specific microsatellites. MSI-H compared to MSI-S is predictive for therapy outcome in chemotherapy and immunotherapy and has been associated with distinct characteristics and favorable results including better prognosis, a higher 5-year survival, and lesser metastasis. Several other tumors also present MSI changes reflecting mismatch repair deficiency. While tumor testing is the gold standard, a convenient approach to screen for MSI before and during cancer treatment is screening circulating DNA (liquid biopsy) using a blood draw, thereby interrogating ‘systemic' MSI reflecting primary or secondary (occult) tumor status at the time of blood collection. However, presence of excess unaltered, wild-type DNA often masks alterations such as MSI. Using capillary electrophoresis or next generation sequencing for MSI detection presents challenges at low levels of MSI due to polymerase slippage (‘stutter') that generate high false positive rates at positions of homo-polymers. We present a new approach for enrichment of altered micro-satellites prior to DNA-amplification thereby facilitating their detection. We recently developed nuclease-assisted minor-allele enrichment with probe-overlap, a single-step approach that removes WT-DNA and enriches mutation-containing alleles. Here we adapted NaME-PrO for detection of homopolymer indels, for MSI detection. The method employs a double-strand-DNA-specific nuclease and overlapping oligonucleotide-probes interrogating multiple micro-satellite targets. Following DNA denaturation, the probes form double-stranded regions with their targets, thereby guiding nuclease digestion to selected sites. Microsatellite indels create ‘bulges' that inhibit digestion, thus subsequent amplification yields DNA with microsatellite alterations enhanced at multiple targets. The assay is applied at the genomic or circulating-DNA level prior to amplification, thereby avoiding polymerase-introduced ‘stutter peaks' arising from WT DNA. Inclusion of organic solvents allows homogeneous application of the method in closed tube reactions. We validated the method by evaluating 5 MSI targets simultaneously, NR27, NR21, NR24, BAT25 and BAT26 using DNA from tumor biopsies and circulating-DNA from colorectal cancer patients. The technique enriched all altered targets and detected microsatellite alterations down to 0.01% altered allele frequency, thus improving detection sensitivity by >100-fold relative to current approaches. We anticipate application of this highly- multiplex-able method either with standard 5-plex reactions in conjunction with capillary electrophoresis or with NGS-based detection of MSI on thousands of targets to enable sensitive detection in tumors and liquid biopsies. Citation Format: Ioannis Ladas, Chen Song, Fangyan Yu, Ka Wai Leong, Katerina Troullinou, Matthew Kulke, Harvey Mamon, Mike G. Makrigiorgos. Sensitive detection of microsatellite instability (MSI) in tumors and liquid biopsies using nuclease-based enrichment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 942.

A model for treating polluted air streams in a continuous two liquid phase stirred tank bioreactor

Biological air treatment systems have been widely under investigation in recent years. Inclusion of non-biodegradable organic solvents to these systems is a way to improve the biotic removal capacity of the systems. In this article the process of absorption and biodegradation of a hydrophobic organic compound in a two liquid phase stirred tank bioreactor has been modeled. Using the model it has been shown that the inclusion of an organic solvent is advantageous if certain conditions are met. Some simulation examples showed that the usefulness of adding an organic solvent to the system depends on kinetic parameters of biological reactions and mass transfer coefficients of pollutants and oxygen between the air and liquid phases. Since different factors influence the process, the usefulness of including an organic solvent to the system should be checked in each special case. The simple model presented in this article can help the prediction of the effect of amending a solvent to the bioreactor under a set of given conditions.

Review: Sample Concentration Based on Inclusion of Organic Solvents in Capillary Zone Electrophoresis

Capillary electrophoresis, as an analytical tool for drugs, offers several advantages for pharmaceuticals and clinical applications; however, it suffers from poor detection limits. Concentration on the capillary (stacking) improves greatly this problem and is very easy to perform. One of the simple and practical methods to perform stacking is dissolving the sample in organic solvents and injecting a large volume of sample on the capillary. This leads to concentration of the sample 10-30 folds directly on the capillary, removes the excess of proteins found in biological fluids and overcomes the deleterious effects of salts. The stacking can be performed in both the hydrodynamic and electroinjection. This stacking brings the detection limits of the CE closer to that of the HPLC. The mechanism, practical applications, different factors, and optimum conditions for this type of stacking are reviewed and discussed.

Triarylmethanol Host Compounds. Synthesis, Crystalline Complex Formation and X-Ray Crystal Structures of Three Inclusion Species

A variety of triarylmethanol compounds including benzo condensed and laterally substituted derivatives 1–10 have been prepared and shown to act as crystallinehosts for the inclusion of organic solvents involving protic polar, aprotic dipolar and apolar molecules. The inclusion ability is ratherhigh for aprotic dipolar solvents while protic polarcompounds are only rarely enclathrated. Host 9 is an exception, being also efficient with alcohols and amines. Compound3 displays no inclusion formation under theexperimental conditions. X-ray crystal structures of the inclusion compound 1⋅acetone (2:1) and of two amineinclusion compounds of host 9 [9⋅ n-propylamine(1:1), 9⋅di-n-propylamine (1:1)] are reported showing the formation of H-bondedhost-guest associates as the common feature of supramolecular association.

Synthesis of Neoglycoconjugates by Transglycosylation with Arthrobacter protophormiae Endo-β-N-acetylglucosaminidase: DEMONSTRATION OF A MACRO-CLUSTER EFFECT FOR MANNOSE-BINDING PROTEINS

The transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae (endo-A) can be enhanced dramatically by inclusion of organic solvent in the reaction mixture (see accompanying article; Fan, J.-Q., Takegawa, K., Iwahara, S., Kondo, A., Kato, I., Abeygunawardana, C., and Lee, Y. C. (1995) J. Biol. Chem. 270, 17723-17729). This finding was extended to synthesis of important intermediates for preparation of neoglycoconjugates. When 0.2 M GlcNAc-O-(CH2)6NH2, GlcNAc-O-CH2CH = CH2, GlcNAc-O-(CH2)3-CH = CH2, GlcNAc-O-(CH2)3NHCOCH = CH2, GlcNAc-S-CH2CN, GlcNAc-S-(CH2)3CH3, or GlcNAc-S-CH2-CONHCH2CH(OMe)2 were used as acceptors in 30% acetone-containing media, the transglycosylation was accomplished with about 80% yield. The transglycosylation yields to benzyl beta-GlcNAc (67%), 4-methyl-umbelliferyl beta-GlcNAc (66%), p-nitrophenyl beta-GlcNAc (33%), and (GlcNAc-beta-S-CH2CH2CH2)2 (43%) were lower, because their poor solubilities allowed only 0.05 M or lower concentrations in the reaction mixture. A micromole-scale synthesis of Man9GlcNAc2-O-(CH2)3-NHCOCH = CH2 (Man9GlcNAc2-NAP) was accomplished with 90% yield, and the structure of the transglycosylation product was confirmed by 1H NMR. Man9GlcNAc2-NAP was co-polymerized with acrylamide. The ratio of sugar side chain to acrylamide in this glycopolymer was 1:44 and the molecular weight of glycopolymer was estimated to be between 1,500,000 and 2,000,000 by high performance gel filtration chromatography. The glycopolymer was shown to be a much more efficient inhibitor of binding by recombinant rat mannose binding protein-carbohydrate recognition domains (MBP-CRD) from serum (I50 = 3.5 microM Man9GlcNAc2-sugar chain) and liver (I50 = 74.5 nM) than soybean agglutinin.

Enhanced Transglycosylation Activity of Arthrobacter protophormiae Endo-β-N-acetylglucosaminidase in Media Containing Organic Solvents

The transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae (endo-A) was enhanced by inclusion of organic solvents in the reaction mixture. In aqueous solution, the transglycosylation yield relative to starting substrate was 32% using Man9GlcNAc2Asn as donor and 0.5 M GlcNAc as acceptor. However, in the media containing 30% (v/v) acetone, dioxane, N,N-dimethylformamide, or dimethyl sulfoxide with 0.5 M GlcNAc as acceptor, the transglycosylation attained yields of 89, 13, 28, and 75%, respectively, as analyzed by high performance anion exchange chromatography. The enzyme was stable in media containing up to 30% acetone, 30% dimethyl sulfoxide, or 20% N,N-dimethylformamide at 37 degrees C for at least 30 min. The acceptor (GlcNAc) concentration must be greater than 0.2 M for efficient transglycosylation. Electrospray mass spectrometry analysis of the transglycosylation product obtained in 30% acetone with Man5GlcNAc2Asn as donor and methyl alpha-2-acetamido-2-deoxy-D-glucopyranoside as acceptor showed a mass ion of m/z 1249.4, consistent with the expected molecular weight. Analysis by 1H NMR of the product revealed that transglycosylation occurred at the C-4 of GlcNAc and the linkage was of the beta-configuration. In the acetone-containing medium, Glc, Man, 2-deoxy-Glc, and methyl alpha-D-GlcNAc can serve as a good acceptor as GlcNAc. Less favorable acceptors are xylose, fructose, 6-deoxy-Glc, and 3-O-methyl-D-glucose. On the other hand, GalNAc, Gal, allose, and 3-deoxy-Glc could not serve as acceptors of the enzyme transglycosylation.

Rapid purification of topoisomerase I from human breast cancer cells by high-performance liquid chromatography

The DNA regulatory enzyme topoisomerase I (TpI) from human breast cancer cells has been analyzed by high-performance liquid chromatography (HPLC) for the first time. Cells were homogenized in Tris buffer and TpI activity was extracted with 0.5 M sodium chloride. Negatively supercoiled plasmid pBR322 was used as the substrate to monitor TpI activity, as judged by relaxed products, analyzed on 1% agarose gels. HPLC in the anion-exchange mode (HPIEC) provided an approximately 6-fold purification of the enzyme. Enhanced purification was subsequently obtained by chromatography of a HPIEC eluate on size-exclusion columns (30- to 60-fold). Recovery of TpI from size-exclusion columns, whether used in multistep analysis or as the first step, was dependent on inclusion of organic solvent, 1-propanol (0.5%, v/v), in the mobile phase. Marked resolution of TpI activity was observed with HPIEC on a SynChrom CM-300 column. Enzyme activity was noted in the void volume, at 150–200 m M phosphate and at 250–350 m M phosphate. TpI purification was 10- and 120-fold in the latter two peaks, respectively. Silver-stained polyacrylamide gels of TpI-containing activity, eluted from a CM-300 column, showed considerable purification of all but the void volume fraction. A distinct protein band at approximately 88–90 kD was seen in the peak eluted from the CM-300 column with 250–350 m M phosphate. These results indicate that HPLC is useful for rapid purification of the labile enzyme, TpI, in the analysis of its structure—function relationship.

C 55 -isoprenoid alcohol phosphokinase: an extremely hydrophobic protein from the bacterial membrane.

C(55)-isoprenoid alcohol phosphokinase, a butanol-soluble enzyme from the membrane of Staphylococcus aureus, has been purified to homogeneity by the inclusion of organic solvents in all of the techniques used. By polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, the enzyme is a single polypeptide chain of molecular weight 17,000. The amino-acid analysis reveals an unusually high content of nonpolar amino acids (58%), the largest amount so far reported in any protein. When equilibrated in butanol-water, enzyme apoprotein is found in the butanol layer. The influence of sodium chloride indicates that the lipid requirement of the enzyme is nonelectrostatic in nature.