Assay transfer

HTS assay transfers often occur across separate sites and require excellent communication and close collaboration. This milestone is often marked with a meeting and documentation generated that records the protocol and the status of the assay results in the hands of the research laboratory. 

The roles and responsibilities of the transfer lab and the receiving lab as well as an outline describing deliverables and timelines should be defined clearly at the initiation of the assay transfer process. Once a transfer protocol is defined, any deviation from the protocol during execution should be discussed in the transfer report. Explanations as to why the deviation is acceptable should be included in the report. The transfer report should also be approved by relevant functional departments. Due to the complexity of multi-site involvement, having a good change control system in place is important for making SOP modifications or updates. 

The following paragraph summarizes the typical steps for an assay transfer ... 

Write an assay transfer protocol with acceptance criteria based on development experiences... 

Troubleshooting examples as part of the assay transfer material is very helpful. 

Assay Transfer 2.0 ml of camphor spirit to a suitable pressure bottle containing 50 ml of freshly prepared dinitrophenylhydrazine TS. Close the pressure bottle, immerse it in a water bath, and maintain at about 75° for l6 hours. Cool to room temperature, and transfer the contents to a beaker with the aid of 100 ml of dilute sulfuric acid (1 in 12). Allow to stand not less than 12 hours at room temperature, transfer the precipitate to a tared filter crucible, and wash with 100 ml of dilute sulfuric acid (1 in 12) followed by 75 ml of cold water in divided portions. Continue the suction until the excess water is removed,dry the crucible and precipitate at 80° for 2 hours, cool, and weigh. The weight of the precipitate so obtained, multiplied by O.U58I, represents the weight of 10 l6 n sample taken. 

Assay. Transfer about 450 mg of dipyridamole, accurately weighed, to a 250 mL beaker, and dissolve in 50 mL of glacial acetic acid. Stir for 30 min, add 75 mL of acetone, and then stir for an additional 15 min. Titrate with 0.1 N perchloric acid VS to a potentiometric end point using a glass electrode and a silver-silver chloride reference electrode system. Perform a blank titration, and make any necessary correction. Each mL of 0.1 N perchloric acid is equivalent to 50.46 mg of... 

Assay Transfer about 2 mL of sample into a tared, glass-stoppered flask, and accurately weigh. Add 40 mL of water, then add phenolphthalein TS, and titrate with 1 N sodium hydroxide. Each milliliter of 1 A sodium hydroxide is equivalent to 60.05 mg of C2H4O2. 

Assay Transfer about 1 g of sample, accurately weighed, into a 1000-mL flask containing 20 mL of water, and dilute to volume with water. Place 10 mL of this solution into a glass-stoppered flask, add 25 mL of sodium hydroxide TS, and allow the mixture to stand for 5 min. Add 25 mL of 0.1 A iodine, stopper the flask, allow the contents to stand in a cold, dark place for 10 min, and add 30 mL of 1 A sulfuric acid. Titrate the excess iodine with 0.1 A sodium thiosulfate, using starch TS as the indicator. Perform a blank determination (see General Provisions), and make any necessary correction. Each milliliter of 0.1 A iodine is equivalent to 0.9675 mg of... 

Assay Transfer about 200 mg of sample, accurately weighed, into a 250-mL beaker, add 50 mL of 1 10 sulfuric acid, allow to stand for at least 3 min, stirring occasionally, and titrate with 0.1 N potassium permanganate to a light pink color that persists for at least 20 s. Calculate the total peroxides, P, as grams of hydrogen peroxide equivalents per 100 g of the sample, by the equation... 

Assay Transfer about 300 mg of sample, accurately weighed, to a 150-mL beaker, dissolve in 1.5 mL of 96%... 

Assay Transfer about 225 mg of sample, previously dried in a vacuum oven at 50° for 2 h and accurately weighed, into... 

Assay Transfer an accurately weighed amount of Sample Solution, equivalent to about 1 g of CaCl2, into a 250-mL... 

Assay Transfer about 1.2 g of sample, accurately weighed, into a 250-mL beaker, and dissolve in 75 mL of water. Add 25 mL of 1 N acetic acid and 1.0 mL of diphenylcarbazone TS, and titrate slowly with 0.1 M mercuric nitrate to the first appearance of a purple color. Each milliliter of 0.1 M mercuric nitrate is equivalent to 37.43 mg of C1oH12CaN2Na208. Lead Determine as directed for the Dithizone Method under Lead Limit Test, Appendix MB, using a Sample Solution prepared as directed for organic compounds, but use 70%... 

Assay Transfer about 1.5 g of sample, accurately weighed, into a beaker, and gradually add 30 mL of 2.7 A hydrochloric acid. When solution is complete, transfer it into a 500-mL volumetric flask, rinse the beaker thoroughly, add the rinsings to the flask, dilute to volume with water, and mix. Transfer 50.0 mL of this solution into a suitable container, and add 50 mL of water. While stirring, preferably with a magnetic stirrer, add about 30 mL of 0.05 M disodium EDTA from a 50-mL buret, then add 15 mL of 1 A sodium hydroxide and 300 mg of hydroxy naphthol blue indicator, and continue the titration to a blue endpoint. Each milliliter of 0.05 M disodium EDTA is equivalent to 3.705 mg of Ca(OH)2. 

Assay Transfer about 1 g of sample, accurately weighed, into an Erlenmeyer flask, add 30 mL of water and 30 mL of 85% phosphoric acid water (1 1 v/v), and titrate immediately with 0.5 N potassium permanganate to the first faint pink color that persists for 1 min. Each milliliter of 0.5 A potassium permanganate is equivalent to 18.02 mg of Ca02. 

Assay Transfer about 300 mg of sample, accurately weighed, into a 250-mL Erlenmeyer flask, add 50 mL of glacial acetic acid, and warm on a steam bath until solution is complete. Cool, add 10 mL of mercuric acetate TS and 2 drops of crystal violet TS, and titrate with 0.1 A perchloric acid in glacial acetic acid to a green endpoint. 

Assay Transfer about 500 mg of sample, accurately weighed, into a 1000-mL volumetric flask, dissolve in and dilute to volume with 0.01 N hydrochloric acid, and mix. Transfer 10.0 mL of this solution into a 250-mL volumetric flask, dilute to volume with 0.01 N hydrochloric acid, and mix. Using a suitable spectrophotometer and 0.01 N hydrochloric acid as the blank, determine the absorbance of this solution and of a similarly prepared solution of USP Disodium Guanylate Reference Standard, at a concentration of 20 p,g/ mL, in 1-cm cells, at the maximum at about 260 nm. Calculate the quantity, in milligrams, of C10H12N5Na2O8P in the sample taken by the formula... 

Assay Transfer about 3 g of sample, previously dried with anhydrous sodium sulfate and accurately weighed, into a 25-x 150-mm test tube. Add 2.100 g of melted o-cresol that is pure and dry, with a solidification point of 30° or higher, to the sample. 

Assay Transfer about 500 mg of sample, accurately weighed, into a 500-mL Erlenmeyer flask, add 25 mL of 2 5 hydrochloric acid, and heat to boiling. Add, dropwise, a solution of 5.6 g of stannous chloride in 50 mL of 3 10 hydrochloric acid until the yellow color disappears, and then add 2 drops in excess. Cool the solution in an ice bath to room temperature, add 8 mL of mercuric chloride TS, and allow to stand for 5 min. Add 200 mL of water, 25 mL of 1 2 sulfuric acid, and 4 mL of phosphoric acid then add orthophenanthroline TS and titrate with 0.1 A ceric sulfate. Each milliliter of 0.1 A ceric sulfate is equivalent to 16.99 mg of C4H2Fe04. 

Assay Transfer about 10 g of sample, previously dried in vacuum at 70° for 4 h and accurately weighed, into a 100-mL volumetric flask, dissolve in 50 mL of water, add 0.2 mL of 15.2 N ammonium hydroxide, dilute to volume with water, and mix. After 30 min, determine the angular rotation [see Optical (Specific) Rotation, Appendix IIB] in a 100- or 200-mm tube at 25° with the sodium D line. The observed rotation, in degrees (absolute value), multiplied by 1.124 (or 0.562 for the 200-mmtube), represents the weight, in grams, of Fructose in the sample taken. 

Assay Transfer 3.5 g of sample, accurately weighed, into a flask, add 40.0 mL of 1 A sodium hydroxide, and rinse the sides of the flask with water. Cover with a watch glass, boil gently for 1 h, cool, and titrate the excess sodium hydroxide with 1A sulfuric acid to pH 6.5. Perform a blank determination (see General Provisions) with the same quantities of the same reagents in the same manner, and make any necessary correction. Each milliliter of 1 A sodium hydroxide is equivalent to 236.3 mg of Q4H20O3, calculated on the dried basis. Acidity Mix 750 mg of sample with 15 mL of water, heat at 80° for 1 min, cool, and filter. The filtrate is acid or neutral to litmus. Add 0.2 mL of 0.1 A sodium hydroxide and 2 drops of methyl red TS to 10 mL of the filtrate. The solution is yellow, without even a light cast of pink. 

Assay Transfer a volume of sample, equivalent to about 300 mg of H2O2 and accurately weighed, into a 100-mL volumetric flask, dilute to volume with water, and mix thoroughly. Add 25 mL of 2 N sulfuric acid to a 20.0-mL portion of this solution, and titrate with 0.1 N potassium permanganate. Each milliliter of 0.1 N potassium permanganate is equivalent to 1.701 mg of H2O2. 

Assay Transfer about 200 mg of sample, previously dried at 105° for 4 h and accurately weighed, to a 250-mL beaker, add 5 mL of a 1 50 mixture of 2 N sulfuric acid acetic anhydride, and cover the beaker with a watch glass. Heat on a steam bath for 20 min, then chill in an ice bath, and add 100 mL of water. Boil for 20 min, allow to cool, and transfer quantitatively, with the aid of a little water, to a 250-mL separator. Extract the solution with six successive 30-, 25-,... 

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