Injectable preparations are also called parenteral preparations. These are sterile preparations, also called parenteral infusion or implantation. Injectable Preparations are sterile preparations and are administered by injection. Injectable preparations should be prepared by methods that ensure Sterility, avoids contamination of foreign matters, pyrogens, Microorganisms, and Bacterial Endotoxins.

Water for injection (WFI) is most commonly used as a vehicle for injectable solutions and suspensions. Other suitable vehicles may be used, provided they are safe in the volume of injection administered, and it should not interfere with the therapeutic efficacy of the formulation. Other additives like Buffers, Antioxidants, Chelating agents, Preservatives and stabilizers can be added to preparations. Colouring agents are not added solely for the colouring purpose of the finished product.
Aqueous preparations administered by Subcutaneous, Intradermal, IM, IV route are made isotonic with blood by adding Sodium Chloride or such a suitable agent. Buffering agents are not used for intraocular or intracardiac injection preparations or products that may gain access to the cerebrospinal fluid. Preservatives are added in multidose containers. Preservatives should not be added when the volume to be injected as a single dose exceeds 15 ml. Each final container of injectable preparation shall be inspected individually.
There are five main types of injectable preparations:
A) Injections.
B) Powder for injection.
C) Intravenous Infusion.
D) Concentrated solutions for injections.
E) Implants.
A. INJECTIONS:
Injections are sterile solutions, emulsions, or suspensions, prepared by dissolving, emulsifying, or suspending the active ingredients and other additives in the water for injection or other suitable non-aqueous vehicles or in a mixture of two if they are miscible.
Standards test for Injections:
1) Particulate Matter: Shall comply with the limit test for Particulate Matters.
2) Uniformity of Content: The preparation being examined complies with the test if in the total samples of 30 containers not more than one individual value is outside the limits 85% to 115% and none is outside the limits 75 % to 125 % of the average values. This test is not applicable for suspensions for injection containing Multivitamins and Trace elements.
3) Extractable Volume:
a) Volumes Less than 5 ml: the average content of 5 containers is not less than the nominal Volumes and not more than 115% of the nominal volumes.
b) Volume more than 5 ml: The average content of 3 containers is not less than nominal volume and not more than 110% of the nominal volumes.
Multidose containers labeled to yield a specific number of doses shall contain a sufficient excess to permit the withdrawal of the designated dosage numbers.
4) Sterility: Should comply it the Test for Sterility.
5) Pyrogen Test: Unless otherwise stated in the individual monograph, when the volume to be injected in a single dose is 10 ml or more, injections shall comply with the test for Pyrogen as per pharmacopoeia unless the test for bacterial endotoxins is prescribed.
6) pH: Shall comply with the specifications.
7) Weight per ml: Shall comply with specifications.
8) Leak test for Ampoules: Ampoules shall be leakproof.
B. POWDER FOR INJECTION:
Powder for injections is a pure, solid substance (including freeze-dried material) distributed in final containers. When shaken with the prescribed volume of the appropriate sterile liquid, rapidly form clear and practically particle-free solutions or uniform suspension.
Standards test Powder for injection :
1) Uniformity of content: As described under injections.
2) Uniformity of Weight: This test is not applicable for Powder for injection required to comply with the test for uniformity of content of all active ingredients. Test complies when more than two weights do not deviate from the average weight by more than 10% and non-deviates by more than 20% from 20 samples.
3) Sterility test: It should comply with the test for Sterility.
4) Loss of drying: It should comply with specifications.
C. INFUSIONS:
Use our sterile aqueous solutions or emulsions with water as the continuous phase. They are free from pyrogens or Bacterial Endotoxins. They are usually made isotonic with blood and do not contain any antimicrobial preservatives.
The standard test for Infusions:
1) Particulate Contamination: Intravenous infusions that are solutions and supplied in a container with a nominal content of 100 ml or more shall comply with the test for particulate matter.
2) Sterility: Shall comply with the test for Sterility.
3) Pyrogen: When no test for bacterial endotoxins is prescribed, intravenous infusions shall comply with the test for pyrogens. Unless otherwise stated in the individual monograph, inject 10 ml per kg of body weight into each animal.
4) Assay of Active ingredients: Shall comply with specifications
5) pH: Shall comply with specifications.
6) Weight per ml: Shall comply with specifications.
7) Filled/Extractable Volumes: Shall comply with specifications.
D. CONCENTRED SOLUTION FOR INJECTION:
Concentrated solutions for injections are sterile solutions intended for administration by injection or by Iv infusion only after dilution with suitable dilution with a suitable liquid. After dilutions, these preparations should comply with the requirements of tests for injection or infusions as appropriate.
E. IMPLANTS:
Implants are sterile solid preparations of size and shape for implantation into body tissues to release active ingredients over an extended period.
The standard test for Implants:
1. Sterility: Shall comply with a test for Sterility.
2. Assay content of active ingredients: Shall comply with specifications.
3. Average Weight of implants: Shall comply with specifications.
4. Rate of Release (Dissolution test): Shall comply with the designed period of release.
5. Hardness: Shall comply with specifications.
6. Other tests: In-house tests if specified.
Related: SOP on cleaning and monitoring aseptic area
CLASSIFICATION OF PARENTERAL PREPARATIONS BASED ON PREPARATION:
1) Small Volume Parenterals (SVP)
2) Large Volume Parenterals (LVP)
Small Volume Parenteral:
- Preparation of small-volume parenteral solutions.
- Preparation of typical suspension formula.
- Then, Prepare typical freeze-dried powdered formula.
- And Last Preparation of typical sterile dry fill powder for constitutions.
Preparations of ophthalmic preparations:
- Ophthalmic solutions.
- Ophthalmic suspensions.
- Ophthalmic gels.
- Preparations of ophthalmic ointments.
- Preparation of intraocular irrigating solutions.
- Intramammary infusions (gels, ointments).
- genetically engineered or biotechnology products. (Vaccines and oxides, recombinant DNA technology products).
- Preparations of liposome and lipid products.
- Implants.
Large Volume Parenteral:
Large Volume Parenteral including; the Preparations contain nominal volumes of a single dose, more than 100 ml.