TLC Systems Research Articles

High Prevalence of the Lung Ultrasound Interstitial Syndrome in Systemic Sclerosis Patients with Normal HRCT and Lung Function-A Pilot Study.

Objective: High-resolution computed tomography (HRCT) may lack sensitivity for the early detection of interstitial lung disease associated with systemic sclerosis (SSc-ILD). Lung ultrasound is an emerging technique for the diagnosis of SSc-ILD. This cross-sectional study aimed to describe the prevalence of ultrasound interstitial syndrome in SSc patients with normal HRCT and pulmonary function tests (PFT). Methods: Thirty SSc patients with normal HRCT, FVC > 80% predicted and DLCO > 70% predicted were included. Echocardiography and PFT including impulse oscillometry and cardiopulmonary exercise testing were performed. Lung ultrasound was analyzed by two blinded operators. Patients were classified into two groups, according to the presence or absence of ultrasound interstitial syndrome, defined as the sum of B-lines in all thoracic areas ≥10 and/or pleural line thickness >3 mm on at least one thoracic area and/or a pleural line irregularity score >16%. Results: Ultrasound interstitial syndrome was present in 12 patients (40%). Inter-reader agreement for the diagnosis of ultrasound interstitial syndrome defined by the Kappa coefficient was 0.93 (95%CI 0.79-1.00). Patients with ultrasound interstitial syndrome were younger (37 years vs. 53 years, p = 0.009), more often had pitting scars (n = 7/12 vs. 3/18, p = 0.045) and had lower FVC (102 vs. 110% pred, p = 0.009), TLC (114 vs. 122% pred, p = 0.042) and low-frequency respiratory system reactance (Xrs5 Z-score 0.16 vs. 1.02, p = 0.018), while pulmonary gas exchange was similar. Conclusions: Ultrasound interstitial syndrome was detected in 12/30 SSc patients with normal HRCT and PFT. Patients with ultrasound interstitial syndrome had differences in lung function consistent with reduced respiratory compliance, suggesting minimal and/or early suspected SSc-ILD.

QSRR modeling of lipophilicity of new spirohydantoin derivatives determined with various TLC systems.

A Quantitative structure-retention relationship (QSRR) analysis has been carried out on the chromatography parameters of lipophilicity of selected spirohydantoins. Multiple linear regression (MLR) was applied for construct the QSRR models. The chromatographic parameters of lipophilicity were determined by reversed-phase thin-layer chromatography. Chromatographic analyses were performed on C-18 modified silica gel with a two-component mobile phase consisting of water and protic organic solvent (ethanol, n-propanol, i-propanol, or t-butanol) in different ratios. QSRR models were built and for additional four aqueous mobile phases: acetone-water, acetonitrile-water, tetrahydrofuran-water, and 1,4-dioxane-water (results published before). In total, chromatographic lipophilicity parameters obtained for two types of organic solvents was subject of the QSRR. The predictive ability of each model was defined by an internal validation coefficient. The best QSRR model for predicting the chromatographic parameter of lipophilicity was obtained for tetrahydrofuran as an organic solvent.

Biomass productivity and characterization of Tetradesmus obliquus grown in a hybrid photobioreactor.

In this study, the effects of CO2 addition on the growth performance and biochemical composition of the green microalga Tetradesmus obliquus cultured in a hybrid algal production system (HAPS) were investigated. The HAPS combines the characteristics of tubular photobioreactors (towards a better carbon dioxide dissolution coefficient) with thin-layer cascade system (with a higher surface-to-volume ratio). Experimental batches were conducted with and without CO2 addition, and evaluated in terms of productivity and biomass characteristics (elemental composition, protein and lipid contents, pigments and fatty acids profiles). CO2 enrichment positively influenced productivity, and proteins, lipids, pigments and unsaturated fatty acids contents in biomass. The HAPS herein presented contributes to the optimization of microalgae cultures in open systems, since it allows, with a simple adaptation-a transit of the cultivation through a tubular portion where injection and dissolution of CO2 is efficient-to obtain in TLC systems, greater productivity and better-quality biomass.

Automated production of [68Ga]Ga-DOTA-exendin-4 via fractionated radionuclide generator elution on a cassette based synthesis module

BackgroundPET/CT imaging of glucagon-like peptide receptor 1 has recently filled a gap in reliably diagnosing insulinoma through non-invasive means. 68Ga-labelled derivatives of exendin-4 show high sensitivity as well as sufficient serum stability to enable routine clinical application. Here, we provide data for automated production of [68Ga][Nle14,Lys40(Ahx-DOTA-Ga)NH2]exendin-4 ([68Ga]Ga-DOTA-exendin-4) on a cassette based synthesis module (Modular-Lab PharmTracer, Eckert & Ziegler) using commercially available cassettes in combination with an approved 68Ge/68Ga generator (GalliaPharm, Eckert & Ziegler). This setup ensured high reproducibility as well as low radiation burden for the production team. Quality control including determination of radiochemical purity was performed by RP-HPLC using a water/0.1 % TFA/acetonitrile gradient on a C18 column. A modified TLC system with ammonium acetate & methanol as mobile phase and a novel limit test for determination of polysorbate 80 content in the final formulation are also described in this study. Main findingsReliable yields as well as high molar activity for patient use were only achieved using a fractionated elution approach. Batch data showed radiochemical purity of >93 % as determined by RP-HPLC and TLC as well as good stability over 2 h post production. Testing for polysorbate 80 confirmed a concentration <1 mg/mL in the final product solution. Specifications for routine production were established based on existing Pharmacopeia monographs for other radiopharmaceuticals and were validated with 5 master batches. ConclusionThe described synthesis method enables reproducible, automated in-house production of [68Ga]Ga-DOTA-exendin-4 for routine clinical application.

Improved quality control of [177Lu]Lu-PSMA I&T

BackgroundTargeted radionuclide therapy with [177Lu]Lu-PSMA I&T (zadavotide guraxetan) has proven high efficacy and safety in treating patients with advanced prostate cancer worldwide. Several methods to determine the radiochemical purity have been reported but also limitations in the HPLC analysis due to retention of the sample and tailing effects when using standard gradients containing trifluoroacetic acid (TFA). We here report on the validation of a method for quality control of [177Lu]Lu-PSMA I&T including determination of radiochemical purity, identity testing and limit test for PSMA I&T by HPLC using a Phosphate buffer /Acetonitrile gradient system, complemented with a TLC system with 0.1N Citrate buffer pH 5 as mobile phase including validation of the methods, batch and stability data as well as identification of the main radiochemical impurity by mass spectrometry.ResultsThe described HPLC method met the defined acceptance criteria in terms of accuracy, specificity, robustness, linearity, range and LOQ. HPLC analysis revealed symmetrical peaks and quantitative recovery from the column. Batch data showed a radiochemical purity > 95% as determined by HPLC, stability data a pronounced degradation due to radiolysis, which could be limited by addition of ascorbic acid, dilution and storage at low temperatures. The main radiochemical impurity was found to be the de-iodinated form of [177Lu]Lu-PSMA I&T. TLC analysis allowed to determine the amount of free Lu-177 even in the presence of DTPA in the final formulation.ConclusionOverall the described combination of HPLC and TLC provides a reliable tool for quality control of [177Lu]Lu-PSMA I&T.

System optimization and validation to improve thin-layer chromatography of roselle calyces (Hibiscus sabdariffa L.) required by the Indonesian Herbal Pharmacopoeia Edition II

Context: Roselle (Hibiscus sabdariffa L.) is one of the traditional crude drugs monographed in the Indonesian Herbal Pharmacopoeia Edition II (IHP II). As per IHP II requirements, a TLC pattern should be used in its authentication. However, the TLC system described for this purpose does not produce a clear reference chromatogram, often leading to inconclusive results. Aims: To develop and validate TLC systems of H. sabdariffa calyces for a better-quality chromatogram than those listed in the IHP II, thereby facilitating crude drugs authentication. Methods: To optimize TLC for H. sabdariffa, sixteen systems, differing in stationary phase, mobile phase composition, and/or visualization reagent were tested. The TLC system was then validated using several parameters such as analyte stability during chromatography, analyte stability in the extract solution and on the TLC plate, stability of the derivatization result, and precision on a plate as well as intermediate precision. Results: Two systems (I and II) were successfully designed and applied to evaluate H. sabdariffa quality. System I used Si gel 60 F254 for the stationary phase, ethyl acetate-formic acid-glacial acetic acid-water (100:11:11:2) for the mobile phase, H. sabdariffa’s ethanol extract (5%, 20 µL) for the test solution, cyanidin 3-O-glucoside (100 ppm, 4 µL) as a reference, no derivatization, and detection with visible light. System II combined Si gel 60 F254 for the stationary phase, ethyl acetate-formic acid-glacial acetic acid-toluene-water (80:11:11:20:19), H. sabdariffa’s ethanol extract (5%, 20 µL) for the test solution, chlorogenic acid (1000 ppm, 2 µL) and caffeic acid (50 ppm, 2 µL) as references, the visualizing reagent NP/PEG, and investigation under 366 nm UV light. Conclusions: Both systems are simple but have good stability and precision, thus facilitating H. sabdariffa calyx authentication and paving the way for developing content analysis methods for H. sabdariffa markers.

Determination of β-blocking receptor drugs in silica gel TLC systems with the mobile phase containing surfactant

Abstract Eight drugs blocking beta-adrenergic receptors activity (acebutolol, alprenolol, atenolol, oxprenolol, labetalol, metoprolol, propranolol and sotalol) were investigated through the use of the thin-layer technique with its mobile phase containing surfactant. Assessment of the effect of surfactant presence and 1-propanol concentration in the mobile phase on the retention and separation of investigated solutes was then carried out wherein the effect of the surfactant concentration on the zone shape properties (asymmetry and tailing coefficient) was investigated. The method was applied for the quantitative analysis of the chosen solutes, and the LOD and LOQ values of chosen were determined. These were as follows: acebutolol – 1.11 and 3.36 μg/spot, metoprolol 1.45 μg/spot, 4.4 μg/spot. The chosen system is environmentally friendly due to using silica gel plates and only 5% of propanol in water.

Analisis fitokimia dan kromatografi lapis tipis ekstrak etanol daun rosella (Hibiscus sabdariffa L.)

Rosella (Hibiscus sabdariffa L) is a plant belonging to the Malvaceae family. This plant is widely used as herbal medicine. Rosella leaves have many compounds that can function as antioxidants and antibacterials. As a crude material for traditional medicine, it is necessary to know the content of secondary metabolites contained in rosella leaves both quantitatively and qualitatively as one of the standardization parameters. The objective of this study was to determine the content of secondary metabolites contained in the ethanolic extract of rosella leaves through phytochemical analysis and Thin Layer Chromatography. Rosella leaf extraction was carried out by maceration method using 70% ethanol as solvent. Testing the content of secondary metabolites in the ethanolic extract of rosella leaves was carried out by phytochemical screening. Furthermore, the TLC test was carried out to confirm the presence of a positive group of compounds on phytochemical screening. Phytochemical screening from rosella leaves extract revealed the presence of alkaloids, flavonoids, saponins and tannins. The TLC system used in this study was able to separate the phytochemical content and gave positive results confirming the phytochemical screening results. The eluent used was chloroform:methanol:acetic acid with a ratio of 14:2:1 obtained spots with an Rf of 0.737 which is similar to the Rf standard of quercetin which is 0.762.

Rapid screening of undeclared hypoglycemics in counterfeit herbal antidiabetic products using HPTLC-MS

Adulterating herbal and dietary supplements with synthetic hypoglycemics is widely practiced, especially in developing and undeveloped countries. A simple, precise, and novel method was developed to simultaneously determine synthetic antidiabetics belonging to different classes, namely biguanide, sulfonylurea, and thiazolidinedione, in counterfeit herbal products as adulterants using HPTLC-MS. The method can simultaneously identify and quantify undeclared synthetic drugs metformin, pioglitazone, glipizide, and glimepiride in herbal as well as dietary supplements. The optimized mobile phase for the TLC system consists of cyclohexane:dichloromethane:1-propanol:saturated solution of ammonium acetate in acetic acid in the ratio of (7:5:2:2, v/v/v/v). The method is highly selective and sensitive for detecting chemicals in complex herbal molecules. Identification and quantification of drugs were performed using the densitometric method. The drugs were confirmed using triple quadrupole mass spectrometry through the MS interface. The screening of market preparations revealed the presence of metformin in two of eight products. This study shows that the method for simultaneous determination of these four drugs can be applied successfully to screen synthetic antidiabetics in the herbal complex matrix as adulterants.

An Examination of the Techno-Economic Viability of Hybrid Grid-Integrated and Stand-Alone Generation Systems for an Indian Tea Plant

All tea plants in India rely on the national grid for their electrical needs and diesel for their thermal energy and transportation, which are encountering high costs, high emissions, and issues of accessibility. In this paper, hybrid renewable systems based on both standalone and grid-connected technologies have been modeled using HOMER Pro software for supplying power to a tea manufacturing plant in a typical rural area in India, namely, Gudalur village (Nilgiris), geographically located at 11°30.2′N and 76°29.5′E, which is presently run by the state grid to meet their energy requirements. The different configurations comprised of Solar PV, biomass, hydro, electrolyzer, boiler, thermal load controller to utilize excess electricity, and waste heat recovery options, and lead-acid batteries were designed to meet 650 kWh/day of electricity for processing units, 101 kWh/day of electricity for general applications, 4,450 kWh/day of thermal energy, and 86.35 kg/day of hydrogen energy. To determine the most feasible system design among various scenarios, several criteria such as NPC, COE, LCOH, and CO2 emission of the system have been investigated. In the case of off-grid hybrid systems, results show the highest NPC of $7.01 M with an LCOE of $1.06/kWh is obtained for the diesel generator/boiler/reformer/TLC system. It is reduced to $1.75 M with an LCOE of −$.420/kWh for the PV/biomass-CHP/hydro/TLC scenario. In a grid-connected system, the maximum NPC of $6.20 M with an LCOE of $0.835/kWh is obtained for a diesel generator/boiler system, and it is reduced to −$10.5 M with an LCOE of −$.240/kWh for the PV/biomass-CHP/hydro/TLC scenario. Additionally, in the off-grid systems, the PV/biomass-CHP/hydro/TLC system has LCOH of $4.27/kg, which is economical with the highest renewable fraction of 93%. The PV/biomass-CHP/hydro/TLC hybrid system has the lowest LCOH of −$64.5/kg with a maximum renewable fraction of 96% in on-grid systems. The findings show that recovering excess electricity and waste heat would increase renewable fraction, decrease the energy cost and emissions from the system, and emphasize the importance of TLC and CHP in HRES. According to the simulation results, the grid-connected system is more cost-effective than a stand-alone system due to the revenue obtained from selling renewable power to the grid.

High performance thin-layer chromatography and in vitro cytotoxic studies on ethanol extract of Matricaria chamomilla L (Asteraceae) flowers

Purpose: To develop a high performance thin-layer chromatography (HPTLC procedure for quantitation of apigenin in ethanol extract of Matricaria chamomilla (Babunaj) flowers, and to evaluate the extract for in vitro cytotoxic effect on MCF-7 cell lines.&#x0D; Methods: Quantification of apigenin was carried out using a CAMAG TLC system. A combination of toluene, ethyl acetate and formic acid (4.5:3.5:0.2 v/v/v) was used as mobile phase, with densitometry detection at 336 nm. The HPTLC procedure was subjected to validation as per ICH guidelines. The cytotoxicity of the extract was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay.&#x0D; Results: A sharp apigenin band at Rf of 0.51 was obtained, and the content of apigenin in the extract was 0.062 % w/w. The detection limit (LOD) and quantification limit (LOQ) were 0.19 and 0.57 ng/band, respectively. MTT assay results indicate that M. chamomilla was cytotoxic to Michigan Cancer Foundation-7 (MCF-7) cells, with half-maximal concentration (IC50) of 74 µg/mL.&#x0D; Conclusion: The developed HPTLC method is linear, precise, accurate and specific for the determination of apigenin. M. chamomilla exerts cytotoxic effect on MCF-7 cell line via induction of apoptosis.

Recent Insights in Barium-131 as a Diagnostic Match for Radium-223: Cyclotron Production, Separation, Radiolabeling, and Imaging.

Barium-131 is a single photon emission computed tomography (SPECT)-compatible radionuclide for nuclear medicine and a promising diagnostic match for radium-223/-224. Herein, we report on the sufficient production route 133Cs(p,3n)131Ba by using 27.5 MeV proton beams. An average of 190 MBq barium-131 per irradiation was obtained. The SR Resin-based purification process led to barium-131 in high radiochemical purity. An isotopic impurity of 0.01% barium-133 was detectable. For the first time, radiolabeling of the ligand macropa with barium-131 was performed. Radiolabeling methods under mild conditions and reaction controls based on TLC systems were successfully applied. Small animal SPECT/ computed tomography (CT) measurements and biodistribution studies were performed using [131Ba]Ba(NO3)2 as reference and 131Ba-labeled macropa in healthy mice for the first time. Biodistribution studies revealed the expected rapid bone uptake of [131Ba]Ba2+, whereas 131Ba-labeled macropa showed a fast clearance from the blood, thereby showing a significantly (p < 0.001) lower accumulation in the bone. We conclude that barium-131 is a promising SPECT radionuclide and delivers appropriate imaging qualities in small animals. Furthermore, the relative stability of the 131Ba-labeled macropa complex in vivo forms the basis for the development of sufficient new chelators, especially for radium isotopes. Thereby, barium-131 will attain its goal as a diagnostic match to the alpha emitters radium-223 and radium-224.

High Performance Thin-Layer Chromatography (HPTLC) data of Cannabinoids in ten mobile phase systems.

This article contains data from triplicate analyses of ten different TLC mobile phase systems from the analysis of 11 cannabinoid standards using HPTLC. The data includes 1) example plate images for 8 mobile phases during evaluation; 2) example table of calculated average, standard deviation, CV% of RF for hexane:acetone (87:13) system during evaluation; 3) images of all case sample plates. The validation of the two chosen mobile phases were done according to the SWGDRUG validation requirements [1]. This data can be used for choosing an alternative mobile phase TLC system for the analysis of cannabinoids. The data described in this article is related to a previous published research article “High Performance Thin-Layer Chromatography (HPTLC) analysis of cannabinoids in cannabis extracts” by Liu, et al. (2020) [2].

Efficacy of Computer-Based Telephone Counseling on Long-Term Adherence to Strength Training in Elderly Patients With Knee Osteoarthritis: A Randomized Trial.

To determine whether the Boston Overcoming Osteoarthritis through Strength Training Telephone-Linked Communication (BOOST-TLC) program, a novel telephone-based, motivational, strength-training exercise-adherence counseling intervention, improved adherence to a strength-training exercise program over 2 years. Participants were recruited for this 2-year, single-blind, parallel-arm randomized controlled trial from knee osteoarthritis patient registries, community newspapers, and online websites in Massachusetts. Eligibility criteria included age 50 years or older, painful knee osteoarthritis, and ability to use a telephone. Exclusion criteria included medical conditions precluding exercise, inflammatory arthritis, current regular strength training, planned knee replacement surgery, dementia, inability to follow exercise instructions, and inability to use the TLC system. After participating in a group exercise class, participants were randomized to receiving motivational telephone calls through the BOOST-TLC program for 24 months or the control. Both control and intervention participants received a monthly automated phone message reminder to continue the program. Exercise adherence was ascertained by a single self-report item scored 0-10, where 10 represented complete adherence. Outcomes were evaluated at 6, 12, 18, and 24 months. A total of 104 subjects were randomized, and 89 subjects (44 control, 45 TLC) completed the 24-month follow-up. There was no significant difference in adherence at 24 months between groups (mean for control group 4.01 [95% confidence interval (95% CI) 3.03, 4.99], mean for TLC subjects 3.63 [95% CI 2.70, 4.56]; P = 0.57). In those with knee osteoarthritis who had participated in an exercise program, frequent motivational telephone reminders did not increase adherence to strength-training exercise.

High performance thin-layer chromatography (HPTLC) analysis of cannabinoids in cannabis extracts

Ten different TLC mobile phase systems were evaluated in triplicate to determine the most effective mobile phase for the analysis of cannabinoids in Cannabis sativa L. products using HPTLC. Retardation factors (RF) were recorded and the resolution was calculated for three major cannabinoids, Δ9-THC, CBD and CBN on all ten systems. HPTLC Silica gel 60 F 254 20×10 cm plates were used for nine systems and a RP-18 WF 254 10×10 cm plate was used for one additional system. Two systems, xylene-hexane-diethylamine (25:10:1) and 6% diethylamine in toluene, gave the best results in separating between the three major cannabinoids and from other phytocannabinoids. Both systems were validated according to SWGDRUG validation requirements and showed excellent precision. The results of the analysis of various cannabis products from casework are presented. Using the proper mobile phase system with HPTLC is a superior method when compared to traditional TLC systems for qualitative identification of the common cannabinoids in cannabis products. This method has the potential to provide better resolution and to generate reports for more convenient documentation for peer review of casework in crime labs.

An alternative and simple synthesis of [14 C]potassium cyanate.

The one-step synthesis of [14 C]potassium cyanate from [14 C]urea is described with product characterization by gravimetric specific activity as well as a novel TLC system. The storage, stability, and repurification of [14 C]potassium cyanate are also discussed.

Alternative Method of Radiochemical Purity Testing for Technetium-99m Tetrofosmin

Tc-99m tetrofosmin is a radiopharmaceutical preparation used in nuclear medicine. Radiochemical purity as main parameter of quality should be more than 90%, and was determined using thin layer chromatography with ITLC-SG as stationary phase and mixture of acetone and dichloromethane as mobile phase. Since ITLC-SG is expensive and the solvent used is rather noxious, an alternative method is expected to replace it for routine QC use. Besides, the radiolabeling capability of Tc-99m in low radioactivity is expected to reduce the utilization of Tc-99m in QC of kits manufacturing. Experiment using SepPak C18 column and TLC system with TLC-SG and ITLC-SG were carried out, then the results were compared. Radiochemical purity measurement using TLC-SG and ITLC-SG showed 99.49 ± 0.78% and 96.17 ± 2.37% respectively with the peaks observed at Rf 0.0 and ∼ 0.5 respectively, whereas that using SepPak C-18 showed RCP of 98.51 ± 0.78%. Various radioactivity of Tc-99m from 2 to 100 mCi have been used to label tetrofosmin kits and the radiolabeling quality were almost the same. It can be concluded that SepPak C18 as well as TLC method using TLC-SG can be used as alternative methods for radiochemical purity measurement of Tc-99m tetrofosmin, and low radioactivity of Tc-99m is sufficient to label tetrofosmin with high radiochemical purity.

Development of a Novel Thin-Layer Chromatographic Method of Screening the Red Beet (Beta vulgaris L.) Pigments in Alimentary Products.

The aim of this study was to develop a thin-layer chromatographic method of qualitative analysis, aiming to confirm the presence of the red beetroot pigments in a given sample. The TLC system developed for this purpose consists of the precoated RP-18 F254s TLC plates and the acetonitrile + methanol + water + glacial acetic acid, 2:7:1:0.1 (v/v/v/v) mobile phase. With the use of this system, a striking horizontal separation of betacyanin pigments is obtained for both the red beetroot juice and the commercial betanin sample (with the left-to-right resolution distance of the two bands equal to ca. 6mm), and a unique pattern of the two skewed chromatographic bands is observed. This striking phenomenon has been given a thorough consideration, and its tentative physicochemical justification was provided, based on analogical cases reported and extensively discussed in our earlier studies. Characteristic fingerprint obtained both for the beetroot juice and the commercial sample of betanin (resembling two slant butterfly wings) can prove very helpful for qualitative confirmation of the presence (or otherwise) of the betanin pigment in the red color juices and beverages, as it was demonstrated upon an example of elderberry juice with a confirmed fortification with the betanin pigment.

Application of Ionic Liquids for the Determination of Lipophilicity Parameters Using TLC Method, and QSRR Analysis for the Antipsychotic Drugs.

Reversed-phase liquid chromatography may cause difficulties, especially in the case of basic drugs due to the strong silanophilic interactions in the partition mechanism. Recently, imidazolium-based ionic liquids additives appeared interesting and a convenient solution for suppressing the harmful effect of free residuals of silanol groups, allowing remodeling of the stationary/mobile-phase system, and thus improving the lipophilicity assessment process. The aim of the study was to evaluate the retention behavior of basic antipsychotics using various RP-LC systems, and compare them with data obtained from the modified ionic-liquids RP-TLC systems, and perform the QSRR analysis. Retention and lipophilicity parameters of diverse antipsychotics have been examined in various RP-LC systems. Lipophilicity indices were compared with miscellaneous computed logP values. Furthermore, a large number of molecular descriptors have been computed and compared using various medicinal chemistry software, in order to contribute to the analysis of QSRR. Designated correlation coefficients showed that lipophilicity parameters from TLC systems without [EMIM][BF4] additive correlates very poor with the calculated logPs indices, whereas the indices from the traditional HPLC and TLC systems (with [EMIM][BF4]) were clearly better. Furthermore, QSRR analysis performed for these experimentally obtained lipophilicity parameters showed significant relationships between the retention constants (ROM, logkw) and the in silico calculated physicochemical molecular descriptors. ILs additive may be a significant factor affecting the lipophilicity of basic compounds, thus their use may be favorable in lipophilicity assessment studies. QSRR models with ILs showed that they may be useful in searching/or predicting HPLC/TLC retention parameters for the new/other antipsychotic drugs.

Working fluids selection from perspectives of heat source and expander for a Trilateral cycle

Abstract This paper selects the working fluids for Trilateral cycle from two unique perspectives. The first aspect is to match the heat sources temperature with the critical temperature of working fluids, in which the thermal efficiency, exergy efficiency and utilization of heat source are chosen as the evaluation indicators. A better performance can be achieved when the heat source temperature approaches to the critical temperature of working fluid. From the aspect of expander, working fluids are selected to reduce volumetric flow ratio of expander and the size of expander, which have the lager vapor pressure at condensing temperature (VP), lager density at expander outlet and lower critical temperature. N-butane and R152a show higher net power output and lower volumetric flow ratio of expander among 13 studied working fluids. Two functions of expander volumetric flow ratio with respect to critical temperature of working fluid and VP have been gotten respectively. Furthermore, it can be concluded the suitable heat source temperature range of a TLC system is moderate temperature.