Parenteral products are those products which are administered by injection. Here injection is a mechanical device use to inject drug solution into the intravenous or intramuscular route. Injections have three parts namely: body, needle, and syringe.
So parenteral preparations or Injectable are the sterile solutions or suspensions of drugs in oily or aqueous vehicles that are injected through mucous membrane or skin into internal body compartment.
Advantages of parenteral products:
1. It may produce immediate response in cases of critical illness.
2. Since the inconsistencies of intestinal absorption not yet been involved the therapeutic response of parenteral drugs can be more easily controlled.
3. Almost 100% bioavailability. Show 100% efficacy.
4. Acid labile drugs can be administered in this root.
5. Some intravenous preparation (e.g. Dextrose, Dextrose and Sodium Chloride etc.) are used to reconstruct to the bloodstream fluid, glucose and electrolytes which have been lost as a result of shock or severe bleeding.
6. Since no time is needed for absorption, injections are selected for emergency drugs.
7. By this route long acting or sustain release medication can be given. E.g. Respiratory Corticotrophin Injection, Sterile Procaine Penicillin suspension and Procaine Penicillin in Oil Injection.
8. It is possible in some instances to localize the action of by injecting it adjacent to tissues . E.g. Nerve block by local anaesthetic in case of dental surgery.
9. Sometimes volumes from fraction of ml to liter can be injected.
10. This is the best suitable route of administration of drugs in handling patients who are non-cooperative, unconscious or are otherwise incapable to take the medicine orally.
11. Patients with repeated vomiting have to administer drugs into parenteral roots.
12. Suitable for administering bitter drugs.
Disadvantages:
1. It is expensive; People may have fear about the Injectable syringes.
2. These products must be maintained strictly to keep them sterile.
3. Specialized equipment as well as trained persons are desired for their administration.
4. These may be painful after administration.
5. Application through wrong routs may prove fats.
6. Daily or frequent administration of injections may pose difficulties to the patient.
7. If the drug produce any toxicity or allergic reaction it is difficult to withdrawal of the drugs because it has been already passed in the systemic circulation. e.g. penicillin in intravenous root may cause allergic reaction which may progress to anaphylactic shock to dead as well.
Criteria of good quality parenteral products:
1) It must be effective
2) Must be stable having satisfactory shelf life.
3) Should be non-allergic and non-irritant.
4) Must be sterile which means free of microbs.
5) It should be free from pyrogens.
6) It should be free from foreign particles like dust, fibers etc.
7) It should be free from chemical contaminants.
8) It should have to be isotonic with body fluids.
9) It should have nothing specific gravity with respect to certain body fluids.
10) Multi-dose injections must contain preservatives.
11) Containers must not affect the products.
12) Excipient must be maintained specific guidelines.
13) Solvent or vehicle used should be pharmacologically inert, non-toxic, physically and chemically stable.
14) Must be isotonic and pH resistant.
