Learning Objective

• Factors to be considered for the design of injectables

General Criteria for Design of Suitable Injectable Formulations

1. Drug solubility
2. Selection of the suitable vehicle
3. Volume of administration
4. Route of administration
5. Site of administration
6. Density factor of the injection
7. Isotonicity and pH of the final preparation
8. Sterilization procedures
9. Selection of packaging contents
10. Storage of the product

The following precautions are to be considered when preparing drug solutions and suspensions intended for injection:

1. Solvents or vehicles must meet standards for purity to ensure the safety for injection.
2. The use of buffers, stabilizers and antimicrobial preservatives are restricted in certain parenteral products.
3. The use of colors is strictly prohibited.
4. Parenteral products should meet sterility standards.
5. Solutions for parenteral use must meet pharmacopoeial standards for particulate matter.
6. Parenteral products must be prepared by specially trained personnel in environmentally controlled areas and under strict sanitation standards.
7. Parenteral products are packaged in special high-quality hermetic containers.
8. Each injection container is filled to a volume in slight excess of the labeled volume to be withdrawn. These overfill permits ease of withdrawal and administration of the labeled volumes.
9. Specific labeling requirements are applicable to injections.
10. Sterile powders intended for solution or suspension immediately prior to injection are frequently packaged as lyophilized or freeze-dried powders to permit ease of solution or suspension upon the addition of the solvent or vehicle.