A phase solubility study was conducted to evaluate the Ks and Ce of ternary mixtures PTS/βCD/PLF. In the present study, excessive quantities of PTS were added to aqueous solution having different concentrations of βCD from 2 mM to 8 mM and PLF (10%). The samples were placed in water shaker bath for seventy-two hours at 25 °C [60 (link),61 (link),62 (link),63 (link)]. After 72 h, the supernatant from each sample was carefully pipetted out and filtered through 0.45 μm membrane filters (“Chromafil®Xtra, Macherey-Nagel GmbH & Co. KG, Düren, Germany”). The drug content in the samples was analyzed by UV spectrophotometer at 318 nm [64 (link),65 (link)]. According to Equation (1), a slope-based calculation of Ks can be performed using the phase solubility plot [66 (link),67 (link),68 ,69 (link)]. Equation (2) was used to calculate Ce for each sample [66 (link),70 (link),71 (link)]. S0 is the equilibrium solubility of PTS in water [72 (link),73 (link)].
Chromafil xtra
Manufactured by Macherey-Nagel
Sourced in Germany
Chromafil Xtra is a membrane filter designed for sample preparation and purification. It is made of regenerated cellulose and features a pore size of 0.45 μm. The product is suitable for clarification and sterilization filtration applications.
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Lab products found in correlation
6 protocols using chromafil xtra
1
Evaluating Ternary Solubility Enhancement
2
Quantification of P3 in Biological Fluids
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Individual standard solutions (0.25–250 ppm) of P3 were prepared in acetonitrile (99.9% LC–MS) (J.T.Baker, Deventer, the Netherlands) in the presence of SP (0.5 or 1.0%), VFS or growth medium (GM) and analyzed after 24h, 48h and 1 week. In order to precipitate the proteins in the biological fluids, 1 ml of acetonitrile (1:1) was added to 1 ml of sample and samples were centrifuged at 13,000 rpm for 10 min and filtered (0.20 mm PVDF membrane; Chromafil®Xtra from Macherey-Nagel®) just before analysis, All samples were analyzed as triplicates. Experiments were performed to confirm that this procedure did not interfere with the concentration of the analyte in the standard solutions.
3
Purification of Sulfated Polysaccharides by Ion Exchange
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The sr-SPs were purified by ion exchange chromatography. Where 300.0 mg of sr-SPs were dissolved in MQ water, filtered at 1 µm (Chromafil Xtra, Macherey-Nagel, Duren, Germany), and loaded to an XK 26 Pharmacia column (500 × 600 mm) manually packed with DEAE-Sepharose fast-flow anionic resin (GE Healthcare, Uppsala, Sweden). The column was coupled in an HPLC system with a diode array detector (Dionex U3000 Thermo, Germering, Germany). The column was initially eluted with distilled water at a flow rate of 4.0 mL/min, followed by an increasing concentration of NaCl solution until 100% 1M NaCl was reached at minute 70 min. Afterward, an isocratic elution of 1M NaCl was maintained until 270 min and returned to 100% distilled water until 350 min. Peaks were recorded by Chromeleon 6.8 software (Thermo Scientific, Illkirch, France) at 230 nm (e.g., Figure 8 ). Three fractions F1, F2, and F3 (80, 160, and 80 mL) were obtained, dialyzed, and lyophilized. Samples were denoted as purified sulfated polysaccharides (p-SPs). All purifications were done in triplicate.
4
Optimizing Ultrasound-Assisted Extraction
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Ultrasound-assisted extraction (UAE) was performed in an ultrasonic bath (Figure 1 ) at 35 kHz at different temperatures (20, 40, and 80 °C) and times (5, 10, and 15 min) in 20 mL test tubes. After the correspondent extraction time, the obtained extracts were centrifuged (Heareus, Multifuge 3 L-R Centrifuge, Thermo Fisher Scientific, San Jose, CA, US) at 25 °C for 15 min and filtered through a 0.25 µm polytetrafluoroethylene (PTFE) syringe-tip filter (Chromafil Xtra, Macherey-Nagel GmbH & Co. KG, Düren, Germany).
5
Insulin secondary structure analysis
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To investigate the secondary structure of insulin in the presence of NaCl, we prepared six samples: three at pH 2 and three at pH 6. Insulin powder was dissolved in NaCl solutions of 100 mM, 250 mM, and 500 mM, respectively, to achieve an insulin concentration of 5 mg mL -1 in each sample. The pH was adjusted to 2 (2.16 ± 0.04) by adding 0.1 M HCl, and to 6 (6.13 ± 0.07) by adding 0.2 M NaOH.
In addition, we prepared samples to investigate the secondary structure of insulin in the presence of PEs and taurocholate. These samples were created by dissolving insulin powder in 50 mM PEs (either sodium caprate or SNAC) and taurocholate (either 3 mM or 15 mM). The concentration of insulin in these samples was 5 mg mL -1 . A sample containing only insulin was also prepared. The pH of these samples was adjusted to 6 by adding 0.2 M NaOH. All samples were filtered through a preconditioned polyamide filter membrane with a 0.2 µm pore size and a 25 mm membrane diameter (Chromafil xtra, MACHEREY-NAGEL), then heated at 65 °C and shaken at 350 RPM for 22 hours using a thermoshaker (Thermoshaker PHMT-PSC24N, Grant bio Instruments).
In addition, we prepared samples to investigate the secondary structure of insulin in the presence of PEs and taurocholate. These samples were created by dissolving insulin powder in 50 mM PEs (either sodium caprate or SNAC) and taurocholate (either 3 mM or 15 mM). The concentration of insulin in these samples was 5 mg mL -1 . A sample containing only insulin was also prepared. The pH of these samples was adjusted to 6 by adding 0.2 M NaOH. All samples were filtered through a preconditioned polyamide filter membrane with a 0.2 µm pore size and a 25 mm membrane diameter (Chromafil xtra, MACHEREY-NAGEL), then heated at 65 °C and shaken at 350 RPM for 22 hours using a thermoshaker (Thermoshaker PHMT-PSC24N, Grant bio Instruments).
6
UA Quantification in Nanocapsules
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The standard UA stock solution was prepared in methanol at 500 µg/ml. Dilutions were performed to obtain solutions with a concentration between 10 and 100 µg/ml. The UA samples corresponded to the supernatant obtained after the ultracentrifugation of UA-loaded nanocapsules, as described in the method applicability section. Standards and samples were suitably diluted in methanol to obtain the desired concentration. These solutions were filtered through a polytetrafluoroethylene filter (PTFE, Chromafil Xtra, 0.2 µm×13 mm, Macherey-Nagel, Düren, Germany) before injection.
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