Phosphate buffer, solution preparation 0.5 molar

The labelling of TATE (AnaSpec) and DOTATATE (piCHEM R D) with [ T]NaI (Nordion) was optimized using the chloramine T method [3.1]. A solution of 10 jxg of peptide in 40 pL of phosphate buffer solution (PBS) (O.IM, pH7.5) was transferred to a reaction vial. After addition of the chloramine T solution (5 jxg/5 LxL) and 5-10 pL of radioiodine solution (37-111 MBq), the vial was carefully vortexed and the reaction was allowed to proceed for 1-3 min at room temperature. The reaction was terminated by addition of the sodium metabisulfite solution (10 pg/5 pL). Studies were carried out by varying the molar ratios of the peptide, the DOTATATE and the radionuclide. Labelling procedures with high activity [ I]NaI were also evaluated employing 1110 and 2775 MBq (30 and 75 mCi), 30 and 100 pg of the peptide, 50 and 100 pg of chloramine T and metabisulfite, respectively. The stability of these preparations was evaluated for 48 h. 

A stuck solution of the test compounds at a concentration of 2000 fig/ml in 0.05 molar phosphate buffer solution at a pH of 6.5 was prepared and twofold dilutions were made with sterile buffer. 1-mI quantities of each dilution were incorporated into 19 ml of brain heart infUsion agar in sterile petri dishes. The hardened surface was inoculated with the test organisms and it was incubated for 18 h at 37 C. 

Results of most previous experiments suggested that tolbutamide forms inclusion complexes with P-cyclodextrin in a 1 1 ratio (34-36V However, tolbutamide consists of two hydrophobic end groups (tolyl and butyl) and can potentially form a 2 1 complex which should provide maximum enhancement of water solubility. The complex was prepared by dissolving both P-cyclodextrin (2 mmoles) arul tolbutamide (1 mmole) in pH 11.0,0.05M phosphate buffer solution (160 ml) at room temperature. Slow precipitation occurred after neutralization to pH 7.0 and then concentration by vacuum evaporatiorL The precipitate was further recrystallized from water. The HNMR spectra of the irutial precipitate and the lecrystallized solid (mp 268 Q showed a molar ratio of 2 1. 

The urethane-doped POC bioelastomers were prepared as follows in the first step, citric acid and 1,8-octanediol were bulk polymerized at 140 °C at the molar ratio of 1 1.1 for achieving POC prepolymers in the second step, the POC prepolymers were dissolved in 1,4-dioxane to form a 3% (wt/wt) solution, and reacted with HDI with stannous octoate as catalyst (0.1%wt) at 55 °C for preparing urethane-doped POC prepolymers at different feeding ratios of 1 0.6, 1 0.9 and 1 1.2 (POC prepolymer/HDI) in the third step, the urethane-doped POC prepolymers were cast into a Teflon mould and allowed to dry with a laminar airflow until all the solvents were evaporated, and then were further maintained in an oven at 80 °C to obtain the cured urethane-doped POC bioelastomers. Tg of the bioelastomers ranged from 0.64 to 5.20 °C. The urethane-doped POC bioelastomers with higher isocyanate content exhibited faster degradation rates, and their mass losses were lower than 16% after 2 months in phosphate buffer solutions. 

The degradable polyester bioelastomers were prepared by the polycondensation of malic acid and 1,12-dodecandiol at the molar ratio of 1 1 and 1 2 (malic acid/l,12-dodecandiol). " The prepolymers from the two monomers were first synthesized at 140 °C, and then were poured into a mould for post curing at 160 °C to achieve the final bioelastomers. The mass losses of the bioelastomers with different curing times were lower than 9% after 30 day degradation in phosphate buffer solutions (pH = 7.4, 37 °Q, and the long curing time caused their degradation rate to decrease. 

Given 0.1 M solutions of Na3P04 and H3PO4, describe the preparation of 1 L of a phosphate buffer at a pH of 7.5. What are the molar concentrations of the ions in the final buffer solution, including Na and H ... 

This is a crystalline product of insulin and an alkaline protein where the protein/insulin ratio is called the isophane ratio. This product gives a delayed and uniform insulin action with a reduction in the number of insulin doses necessary per day. Such a preparation may be made as follows 1.6 g of zinc-insulin crystals containing 0.4% of zinc are dissolved in 400 ml of water, with the aid of 25 ml of 0.1 N hydrochloric acid. To this are added aqueous solutions of 3 ml of tricresol, 7.6 g of sodium chloride, and sufficient sodium phosphate buffer that the final concentration is As molar and the pH is 6.9. 

Method. Solutions of amino acids in phosphate buffer (pH 9.3) are mixed with an equal volume of freshly prepared 0.4 M pyridoxal solution (adjusted to pH 9.3) and permitted to stand at 8 °C for 30 min. (The molar ratio of pyridoxal to amino acid should be >75 1.) At this point, 1 ml of sodium tetrahydroborate solution (100 mg/ml in 0.1 N sodium hydroxide) is added and the contents are gently shaken. Excess of sodium tetrahydroborate is destroyed by addition of sufficient hydrochloric acid (pH 1-2) prior to column chromatography. The pyridoxal derivatives are separated on a column (100 X 0.6 cm) of Aminex A-5 ion-exchange resin (Bio-Rad) at a mobile phase flow-rate of 33 ml/h. The eluting solvents consist of 0.2 N buffers at pH 3.40,4.44 and 4.86 and a 0.35 N buffer at pH 5.86 (all of the buffers are sodium citrate). The separation of a number of pyridoxyl-... 

Triethylaminoethyl cellulose powder (Serva) of capacity 0.71 m.equiv./gm is suspended in 2 M sodium chloride buffered with 0.1 M tris/phosphate pH 6.0 and the slurry is packed into a glass column 3.6 cm in diameter until the height of the packed material reaches 20 cm. The column is washed with a further 2 L of the solvent used for preparing the slurry and is then equilibrated with 0.01 M tris/phosphate buffer pH 8.5. Tris is an abbreviation for tris(hydroxymethyl)aminomethane. 330-360 mg of crude A. rhodostoma venom is dissolved in 20 ml of 0.01 M tris/phosphate buffer pH 8.5, centrifuged to remove insoluble material, and the clear supernatant is applied to the column. The fractionation is carried out at room temperature at a flow rate of 90-100 ml (35 ml/hour). The protein concentration in the eluate is estimated from the extinction of the solution at 280 m/t in 1 cm cells. The chromatogram is developed with the following buffers. In all cases the molarity of the buffers are with respect 40 to tris. 

Preparation of a Phosphate Buffer What molar ratio of HPC>1 to H2P04 in solution would produce a pH of 7.0 Phosphoric acid (H3P04), a triprotic acid, has 3 pKa values 2.14, 6.86, and 12.4. Hint Only one of the pKa values is relevant here. 

Standard curve A series of dilutions of bovine serum albumin in isotonic 5 mM phosphate buffer, pH 7.4, are prepared containing between 0 and 100 pg protein in 0.1 ml volume and the assay is performed as described above on each dilution. The exact concentration of the bovine serum albumin stock solution is determined using the molar absorption coefficient of 45000 for bovine serum albumin at 279 nm after diluting to approximately 0.2 g/1. 

Before crystallization trials, the protein was subjected to gel filtration on Superdex-75 (Pharmacia) in 50 mM sodium/potassium phosphate buffer, pH 7.4, containing 1 mM EDTA, 50 mM 2-mercaptoethanol, 150 mM sodium chloride, 5% glycerol and 5% 2-propanol, as described previously (12). The statine-based inhibitor, LP-149 (Ac-Nal-Val-Sta-Glu-Nal-NH2 e Nal is naphtylalanine and Sta is statine) (Fig. 1), was prepared at Lilly Research Laboratories (K. Hui, unpublished results). Crystallization was carried out at 4 °C using the hanging-drop vapor diffusion method as follows 2.5 //I of the FIV PR(D30N) at 7 mg/ml complexed with LP-149 (1 4 molar ratio) in 50 mM imidazole-HCl pH 7.0 containing ImM EDTA and 1 mM dithiothreitol were mixed with an equal volume of 2 M ammonium sulfate, 0.1 M sodium acetate, pH 4.6 (Hampton Crystal Screen, solution 47). Crystals appeared within a few days and reached the size of 0.2 x 0.2 X 0.4 mm in one week. 

Synthesis of Maduramicin-Protein Conjugates. The mixed anhydride method (16) with some modifications (Tsou, H. personal communication) was used to prepare the BSA or OA conjugates to maduramicin (M-BSA, M-OA). A small amount of tritiated maduramicin was added to 100 mg of non-radioactive maduramicin resulting in a specific activity of 23 xCi/gm. Fifty microliters of triethylamine was added to the dried maduramicin followed by the addition of ethyl chloroformate. The mixture was allowed to react for 30 minutes at 4 C with stirring. The conjugating protein BSA or OA was dissolved in water followed by the addition of dimethylformamide to a final concentration of 50%. The final concentration of the protein was about 2 mg/mL. The maduramicin anhydride was added to the cold protein solution dropwise with stirring. The molar ratio of maduramicin to protein was 40 1. The reaction was carried out at 4 C for 3 1/2 hours. The product was dialyzed against 0.01 M sodium phosphate buffer pH 7.4 at 4°C until the radioactivity of the dialysate was below 50 dpm/mL. Estimation of the extent of... 

The ultraviolet absorption spectra for lomefloxacin were obtained on a Hewlett Packard 8451A Diode Array Spectrophotometer as a function of pH. The lomefloxacin solutions were prepared in 0.15 M acetate buffer, 0.05 M phosphate buffer, and 0.15 M borate buffer ( i = 0.15 M with NaCl) at pH 5,7, and 9, respectively. These spectra are given in Figure 13. The molar absorptivities (a) and absorption maxima as a function of pH are summarized in Table 3. 

The reactions were carried out in a thermostatted cuvette (30" C) and were followed by monitoring the decay of the Soret band of the oxoiron(IV) porphyrin (X. ,j 420 nm) with a Hewlett Packard 8452 diode array spectrometer. The standard method involved preparing the oxoiron(lV) species by the addition of a half molar equivalent of 3CPBA to IxlO" mol dm" Fe TDCSTP in 0.025 mol dm aqueous phosphate buffer (pH 6.93) and ionic strength 0.05 mol dm (maintained with NaNOj). The reaction was initiated by the addition of a solution of the dye (final concentration 5x10 to 5x10 mol dm ) in the same aqueous buffer. 

Yang et al. systemically investigated the preparation, aggregation properties and drug release behaviour of PLA/PEG stereo-complex mi-celles. °° Predetermined amounts of PLLA/PEG or PDLA/PEG copolymer are separately dissolved in distilled water or phosphate buffered saline (PBS). The two solutions with equal molar concentrations are then mixed to yield a micellar solution by self-assembly due to interactions between l-LA and d-LA blocks. ... 

The standard solutions used to calibrate MIMS can be readily prepared according to well-established methods. Free chlorine can be purchased in the form of sodium hypochlorite (NaOCl) solution. It can be standardized by either the UV absorbance of OCl at 292 nm (eoa max = 350 M/cm, 25°C and pH > 9.5) [24,28,29] or standard diethyl-p-phenylenediamine (DPD) titration [30]. Standards containing monochloramine and dichloramine can be prepared by slowly pouring a free chlorine solution over an ammonium chloride solution at a chlorine-to-ammonia molar ratio of 1.31 1.00 under rapid stirring. One should wait for 1 h for the reactions to complete in darkness [3]. Standards of trichloramine can be prepared similarly but at a chlorine-to-ammonia molar ratio of 3.15 1.00. The pH of the standard solution can be adjusted to that of the sample solution by phosphate buffers. The standard solutions can be standardized by DPD titration [30]. 

Protein solutions, made up in either phosphate buffer or in double distilled water, was diluted to final concentration (1 mg/ml) by addition of amphiphile solution of appropriate concentration. Protein and monocaproin solutions were freshly prepared, while the diluted SDS solutions were made up from a stock solution (0.5 mM). To avoid precipitation at low molar ratios of the anionic amphiphile-pro-tein complexes, the experiments were performed at pH 5.6, i.e. at the alkaline side of the isoelectric point of the proteins. All measurements were performed at 23 0.5°C. 

Highly-polymerized deoxyribonucleic acid, (DNA), from calf-thymus, was purchased from Sigma Chem. Co. and used as received. Stock solutions of DNA were prepared by dissolution overnight in 5 mM phosphate pH 7 buffer and were stored at 4°C in the dark for short periods only. Concentrations of DNA per nucleotide phosphate were determined by absorption spectroscopy using a molar extinction coefficient of 6,600 M cm at 260 nm [4]. N,N -Dimethyl-2,7-diazapyrenium dlchloride (DAP " ") was prepared and purified according to the method of HUnig et al. [5] whereas ethidium bromide (EB ) was purchased from Sigma Chem. Co. and used as received. 

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