Intravenous solutions with heparin sodium (derived from porcine intestinal mucosa) are sterile, nonpyrogenic fluids for intravenous administration. Each 100 mL contains heparin sodium 200 USP Units; sodium chloride, 0.9 g; citric acid, monohydrate, 40 mg and dibasic sodium phosphate, heptahydrate, 434 mg added as buffers. Each liter contains the following electrolytes: Sodium 186.4 mEq; phosphate (as HPO4=) 32.4 mEq, citrate 5.7 mEq and chloride 154 mEq. Osmolar concentration, 378 mOsmol/liter (calc.); pH 7.0 (5.0 – 7.5).
Heparin Sodium, USP is a heterogeneous group of straight-chain anionic mucopolysaccharides, called glycosaminoglycans having anticoagulant properties. Although others may be present, the main sugars occurring in heparin are: (1) α-L-iduronic acid 2-sulfate, (2) 2-deoxy-2-sulfamino-α-D-glucose-6-sulfate, (3) β-D-glucuronic acid, (4) 2-acetamido-2-deoxy-α-D-glucose, and (5) α-L-iduronic acid. These sugars are present in decreasing amounts, usually in the order (2) > (1) > (4) > (3) > (5), and are joined by glycosidic linkages, forming polymers of varying sizes. Heparin is strongly acidic because of its content of covalently linked sulfate and carboxylic acid groups. In heparin sodium, the acidic protons of the sulfate units are partially replaced by sodium ions. The potency is determined by a biological assay using a USP reference standard based on units of heparin activity per milligram.
Structure of Heparin Sodium (representative subunits):
Sodium Chloride, USP is chemically designated NaCl, a white crystalline compound freely soluble in water.
Dibasic Sodium Phosphate, USP (Heptahydrate), is chemically designated (Na2HPO4 ∙ 7H2O), colorless or white granular salt freely soluble in water.
Citric Acid, USP, hydrous (monohydrate) is chemically designated C6H8O7 ∙ H2O, colorless, translucent crystals or white crystalline powder very soluble in water. It has the following structural formula:
Water for Injection, USP is chemically designated H2O.
The flexible plastic container is fabricated from a specially formulated polyvinylchloride. Water can permeate from inside the container into the overwrap but not in amounts sufficient to affect the solution significantly. Solutions inside the plastic container also can leach out certain of its chemical components in very small amounts before the expiration period is attained. However, the safety of the plastic has been confirmed by tests in animals according to USP biological standards for plastic containers.