L-Cysteine Hydrochloride 50 mg/mL Injection
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`PUBLISHED SEPTEMBER 20, 2011
`L-Cysteine Hydrochloride 50 mg/mL Injection
`
`Loyd V. Allen, Jr., PhD
`Professor Emeritus
`College of Pharmacy, University of Oklahoma
`Oklahoma City, Oklahoma
`
`US Pharm. 2011;36(9):41-42.
`
`Method of Preparation: Note: This formulation should be prepared
`according to strict aseptic compounding technique in a laminar airflow
`hood in a cleanroom or via isolation barrier technology by a
`compounding pharmacist who is validated in aseptic compounding.
`This is a high-risk preparation.
`
`https://www.uspharmacist.com/article/l-cysteine-hydrochloride-50-mgml-injection
`
`5/7/2020
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`Nexus Ex. 1020
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`L-Cysteine Hydrochloride 50 mg/mL Injection
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`Calculate the quantity of each ingredient for the amount to be prepared.
`Accurately weigh or measure each ingredient. Mix the cysteine in about
`40 mL of Sterile Water for Injection. Add sufficient hydrochloric acid 2N
`solution to a pH of 1 to 2.5 to form a clear solution. Add sufficient
`Sterile Water for Injection to final volume; mix well. Filter into sterile
`containers. Package and label.
`
`Use: This injection solution is intended for use only after dilution as an
`additive to crystalline amino acid injections to meet the nutritional
`amino acid requirements of infants receiving total parenteral nutrition
`(TPN).
`
`Packaging: Package in tight, light-resistant containers.
`
`Labeling: Keep out of the reach of children. Discard after ____ [time
`period]. Protect from light. Discard if precipitation occurs. Store at
`controlled room temperature. Do not freeze.
`
`Stability: A beyond-use date of up to 24 hours at room temperature or 3
`days in the refrigerator may be used if not sterility tested. If sterility
`tested, a beyond-use date of up to 6 months may be used.
`1
`
`Quality Control: Quality-control assessment can include weight/volume,
`physical observation, pH, specific gravity, osmolality, assay, color,
`clarity, particulate matter, sterility, and pyrogenicity.
`2,3
`
`Discussion: Premature or sick infants may receive TPN before starting
`other feedings or when they cannot absorb nutrients through the
`gastrointestinal tract for a significant period of time. TPN confers a
`level of nutrition that is superior to standard IV feedings, which provide
`simply sugars and salts. L-Cysteine hydrochloride 50 mg/mL injection is
`used for TPN in infants.
`4
`
`L-Cysteine hydrochloride 50 mg/mL injection has been in short supply.
`The formulation presented here can be compounded for use until the
`manufactured product is available.
`
`https://www.uspharmacist.com/article/l-cysteine-hydrochloride-50-mgml-injection
`
`5/7/2020
`
`Nexus Ex. 1020
`Page 2 of 5
`
`

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`L-Cysteine Hydrochloride 50 mg/mL Injection
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`Page 3 of 5
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`Cysteine Hydrochloride Injection, USP, is a sterile solution of cysteine
`hydrochloride in water for injection. It is a clear, colorless solution with
`an odor of sulfide. It contains not less than 85.0% and not more than
`115.0% of the labeled amount of cysteine hydrochloride. The product
`contains not more than 0.7 USP endotoxin units per mg of cysteine
`hydrochloride and has a pH between 1.0 and 2.5.
`5
`
`L-Cysteine hydrochloride (L-cysteine, L-cysteine ethylester
`hydrochloride, C H NO S.HCl.H 0, MW 175.63) is a nonessential amino
`3
`7
`2
`2
`acid in human development. It is freely soluble in water, alcohol, acetic
`acid, and ammonia water, but is insoluble in ether, acetone, ethyl
`acetate, benzene, carbon disulfide, and carbon tetrachloride. In neutral
`or slightly alkaline aqueous solutions, it is oxidized to cystine by air. It is
`more stable in acidic solutions.
`
`Hydrochloric acid (HCl, MW 36.46) occurs as a clear, colorless, fuming
`aqueous solution of hydrogen chloride that has a pungent odor.
`Concentrated hydrochloric acid is 36.5% to 38.0% w/w concentration. It
`has a specific gravity of 1.18 g/cm , is miscible with water, and is
`3
`soluble in ethanol. The pH of a 10% v/v aqueous solution is 0.1.
`Hydrochloric acid should be stored in well-closed glass or other inert
`containers.
`6
`
`Sterile Water for Injection is water for injection that has been sterilized
`and suitably packaged; it contains no added substances. Water for
`injection is water purified by distillation or reverse osmosis and
`contains no added substances. Water for injection is not prepared by an
`ion-exchange process. The term water is used to describe potable water
`from a public water supply that is suitable for drinking and is the
`beginning point of the official waters. It is a clear, colorless, odorless,
`and tasteless liquid. Purified water is obtained by distillation, ion
`exchange, reverse osmosis, or other suitable process. Water has a
`specific gravity of 0.9971 at room temperature, a melting point of 0°C,
`and a boiling point of 100°C. It is miscible with most polar solvents and
`is chemically stable in all physical states (ice, liquid, and steam).
`7
`
`https://www.uspharmacist.com/article/l-cysteine-hydrochloride-50-mgml-injection
`
`5/7/2020
`
`Nexus Ex. 1020
`Page 3 of 5
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`

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`L-Cysteine Hydrochloride 50 mg/mL Injection
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`REFERENCES
`1. USP Pharmacists’ Pharmacopeia. 2nd ed. Rockville, MD: US Pharmacopeial Convention, Inc;
`2008:775-779,797-831.
`2. Allen LV Jr. Standard operating procedure for particulate testing for sterile products. IJPC.
`1998;2:78.
`3. Allen LV Jr. Standard operating procedure: quality assessment for injectable solutions. IJPC.
`1999;3:406-407.
`4. Total parenteral nutrition—infants. Medline Plus. www.nlm.nih.gov/medlineplus/
`ency/article/007239.htm. Accessed August 12, 2011.
`5. U.S. Pharmacopeia 34/National Formulary 29. Rockville, MD: US Pharmacopeial Convention,
`Inc; 2011:2464.
`6. Quinn ME, Sheskey PJ. Hydrochloric acid. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook
`of Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:308-309.
`7. Dubash D, Shah U. Water. In: Rowe RC, Sheskey PJ, Quinn ME, eds. Handbook of
`Pharmaceutical Excipients. 6th ed. London, England: Pharmaceutical Press; 2009:766-770.
`
`To comment on this article, contact rdavidson@uspharmacist.com.
`
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`https://www.uspharmacist.com/article/l-cysteine-hydrochloride-50-mgml-injection
`
`5/7/2020
`
`Nexus Ex. 1020
`Page 4 of 5
`
`

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`L-Cysteine Hydrochloride 50 mg/mL Injection
`
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`https://www.uspharmacist.com/article/l-cysteine-hydrochloride-50-mgml-injection
`
`5/7/2020
`
`Nexus Ex. 1020
`Page 5 of 5
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