Tonicity agents

TONICITY AGENTS OTHER THAN SODIUM CHLORIDE... 

Step 4 From Step 3, 0.231 g of sodium chloride is required to make the preparation isotonic. But the prescription calls for boric acid as the tonicity agent. Boric acid has an E value of 0.52. This means that 1% boric acid is osmotically equivalent to 0.52% NaCl or 1 g of boric acid is equivalent to 0.52 g of NaCl. 

Tonicity agents are added to injectable preparations to prevent osmotic shock at the site of injection upon administration, and thereby reduce local irritation. Typical excipients used for tonicity adjustment include saline, glycerin, mannitol, dextrose, and trehalose. Tonicity is a colligative property that depends primarily on the number of dissolved particles in solution. Hence, the amount of tonicity agent to be added depends on the specific formulation. Typically, osmolality of 280 to 320mOsm is considered iso-osmotic. 

A liquid formulation is usually comprised of a buffering agent, a stabilizer (which may also serve as a tonicity agent), a surfactant, and an anti-oxidant when protein oxidation is significant. Chelating agents are employed when metal ion catalyzed reactions predominate. A preservative may be included when a multi-dose formulation is desired. 

Tonicity agent/stabilizer Provides isotonicity to the formulation such that it is suitable for injection Examples include polyols, salts, and amino acids Help maintain the protein in a more compact state (polyols) Minimize electrostatic, solution protein-protein interactions (salts) Stabilizers include cryo and lyoprotectants Examples include polyols, sugars, and polymers Cryoprotectants protect proteins from freezing stresses Lyoprotectants stabilize proteins in the freeze-dried state... 

Several good surfactants in terms of solubility, compatibility, and toxicity can be selected for prototype formulation development. In general, one surfactant can be used as the primary solubilizer in a prototype formulation. Functional excipients, such as antioxidants, tonicity agents for parenteral products and sweeteners, and taste masking agents for oral products, may be added to the prototyp formulation. 

Tonics—agents that strengthen an organ or organ system. 

Tablet and capsule diluent therapeutic agent tonicity agent sweetening agent.

Antimicrobial preservative emollient humectant plasticizer solvent sweetening agent tonicity agent. 

Diluent diluent for lyphilized preparations sweetening agent tablet and capsule diluent tonicity agent. 

Glycerin Isuprel Co-solvent Humectant Preservative Tonicity agent 7.3%... 

Hypotonic ophthalmic solutions or suspensions can be rendered isotonic by the addition of tonicity agents such as sodium chloride, potassium chloride, dextrose, glycerol and buffering salts. As with other adjuvants, the formulator should give due consideration to possible interactions between the tonicity agent and other components of the formulation, including the drug itself. 

Tonics.—Agents which g dually improve the condition and functions of the digestive organs, so as to enable the system to acquire increased vigour. 

Uses Sweetener in foods and pharmaceuticals tonicity agent in pharmaceuticals... 

Black haw (Viburnum prunifolium) bark extract tonic, vomiting treatment Phosphoric acid tonicity agent, pharmaceuticals Glucose D-Clucose monohydrate D-Mannitol ... 

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