(A) Freezing point depression method 1- What is the amount of NaCl required to make a 30 ml ophthalmic solution containing 0.5% (w/v) pilocarpine and 2% (w/v) procaine, isotonic with the lachrymal fluid? Freezing point depression of 1% solution of pilocarpine = 0.14 Freezing point depression of 1% solution of procaine = 0.11 Freezing point depression of 1% solution of sodium chloride =0.576 2- What is the amount of NaCl required to make a 25 ml ophthalmic solution containing 0.5% (w/v) ephedrine-HCl and 1.2% (w/v) boric acid, isotonic with the lachrymal fluid? Freezing point depression of 1% solution of ephedrine-HCI= 0.18 Freezing point depression of 1% solution of boric acid = 0.29 Freezing point depression of 1% solution of sodium chloride =0.576 (A) Freezing point depression method 1- What is the amount of NaCl required to make a 30 ml ophthalmic solution containing 0.5% (w/v) pilocarpine and 2% (w/v) procaine, isotonic with the lachrymal fluid? Freezing point depression of 1% solution of pilocarpine = 0.14 Freezing point depression of 1% solution of procaine = 0.11 Freezing point depression of 1% solution of sodium chloride =0.576 2- What is the amount of NaCl required to make a 25 ml ophthalmic solution containing 0.5% (w/v) ephedrine-HCl and 1.2% (w/v) boric acid, isotonic with the lachrymal fluid? Freezing point depression of 1% solution of ephedrine-HCI= 0.18 Freezing point depression of 1% solution of boric acid = 0.29 Freezing point depression of 1% solution of sodium chloride =0.576