DRUG DOSAGE FORMS & DELIVERY SYSTEMS


Injections / Injectables

Injections are sterile, pyrogen limited, that is, bacterial endotoxin units limit, preparations intended to be administered parenterally. The term parenteral refers to the injectable routes of administration. It derives from the Greek words para (outside) and enteron (intestine) and denotes routes of administration other than the oral route. Pyrogens, or bacterial endotoxins, are organic metabolic products shed from Gram-negative bacteria which can cause fever and hypotension in patients when they are in excessive amounts in intravenous (IV) injections.

Intravenous Route - IV drugs provide rapid action compared with other routes of administration, and because drug absorption is not a factor, optimum blood levels may be achieved with accuracy and immediacy not possible by other routes. In emergencies, IV administration of a drug may be lifesaving because of the placement of the drug directly into the circulation and the prompt action that ensues.

Intramuscular Route - IM injections of drugs provide effects that are less rapid but generally longer lasting than those obtained from IV administration. Aqueous or oleaginous solutions or suspensions of drug substances may be administered intramuscularly. Depending on the type of preparation, absorption rates vary widely. Drugs in solution are more rapidly absorbed than those in suspension, and drugs in aqueous preparations are more rapidly absorbed than oleaginous preparations. The physical type of preparation is based on the properties of the drug itself and on the therapeutic goals

Subcutaneous Route - The SC route may be used for injection of small amounts of medication. Injection of a drug beneath the skin is usually made in the loose interstitial tissue of the outer upper arm, the anterior thigh, or the lower abdomen. The site of injection is usually rotated when injections are frequently given, as with daily insulin injections. Prior to injection, the skin at the injection site should be thoroughly cleansed.

Intradermal Route - A number of substances may be effectively injected into the corium, the more vascular layer of the skin just beneath the epidermis. These substances include various agents for diagnostic determinations, desensitization, or immunization.

Official Type of Injections

  1. Injection: Liquid preparations that are drug substances or solutions thereof (e.g., Insulin Injection, USP).
  2. For injection: Dry solids that, upon addition of suitable vehicles, yield solutions conforming in all respects to the requirements for injections (e.g., Cefuroxime for injection, USP).
  3. Injectable emulsion: Liquid preparation of drug substance dissolved or dispersed in a suitable emulsion medium (e.g., Propofol, USP).
  4. Injectable suspension: Liquid preparation of solid suspended in a suitable liquid medium (e.g., Methylprednisolone Acetate Suspension, USP).
  5. For injectable suspension: Dry solid that, upon addition of suitable vehicle, yields preparation conforming in all respects to the requirements for injectable suspensions (e.g., Imipenem and Cilastatin for injectable suspension, USP)