NaCl needed to make isotonic, One drug

8. Buffer and Isotonic Solution 8.2) Isotonic Solution 8.2.2) NaCl needed, One drug

8.2.2.1) NaCl needed, One drug Easy 1


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Calculate the gram amount of NaCl required to make the following sterile product isotonic.


      Rx:
      Drug ABC: 0.95 %
      NaCl qs
      Aqua dist q.s. a.d. 70 mL
      M.ft. isotonic solution
      Provided, the E value of the drug is 0.12 .


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lb equals 0.550 g kg

    Answer: 0.5502 grams of NaCl will be needed.
    • Volume of the product: 70 mL
    • Concentration of the drug: 0.95 %.
    • Amount of NaCl needed to prepare an isotonic solution of this volume: 0.9/100 × 70 = 0.63 g
    • Quantity of the drug present in the solution: 0.95 /100 × 70 = 0.665 g
    • E value of the drug (provided): 0.12
    • Now, the NaCl-equivalent tonicity contributed by the drug will be the product of drug's weight in g (0.665) and its E value ( 0.12 ), which is: 0.665 × 0.12 = 0.0798 g
    • Therefore, the quantity of additional amount of NaCl required to make the product isotonic: 0.63 g - 0.0798 g = 0.5502 g