Overview Of Pharmaceutical Parenteral Preparations

Parenteral preparations are defined as solutions, suspensions, emulsions for injection or infusion, powders for injection or infusion, gels for injection and implants. They are sterile preparations intended to be administered directly into the systemic circulation in humans or animals.

Parenteral product

They are usually supplied in single dose glass or plastic containers (PVC nowadays less recommended, or polyolefin) or more and more in pre-filled syringes or pens to facilitate the ease of use.

Parenteral preparations are intended to be administered through the human or animal body, either by direct injections (for example, bolus intravenous (IV), intramuscular (IM) or subcutaneous (SC)) or by infusion with a controlled infusion rate or by direct implantation through IM or SC.

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Properties of Parenteral Preparations

1. To be sterile and pyrogen-free

2. To be clear or practically exempt of visible particle and to be free from sub-visible particles as required by pharmacopoeia EP, USP and JP

3. No evidence of phase separation for the emulsions, or aggregates formation for aqueous dispersions such as injectables Mab (monoclonal antibody) preparations

4. In case of suspensions, the use of appropriate particle size and any sediment should be readily dispersed upon shaking to give stable formulations and ensure the correct dose to be withdrawn and injected.

Function Of Excipients Use In Parenteral Preparations

1. To make the preparations isotonic with respect to blood (glucose/dextrose, mannitol, sodium chloride)

2. To adjust the pH to the physiological one (mineral or organic acids or salts)

3. To prevent the degradation of the drug substances (stabilizer)

4. To ensure or increase the drug substance’s solubility

5. To provide adequate antimicrobial preservative property (only applicable to multi dose preparations)

Quality Of Parenteral Preparations

The ingredients must be compatible with each other and the container. The bottle should not leech into the contents. Also, the product must be soluble and remain so during administration.

The pH of the product should be close to physiological pH. Compromise should be made when stability of the drug will be affected by the pH. However, preparation above 200ml should not be formulated with pH buffers as the blood already has a buffer effect property that could enter into competition with the injected product.

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A Small amount of each excipient should be used at all times. Solutions should be pyrogen free.

Advantage Of Parenteral Preparations

1. Faster onset of action

2. Suitable for drugs that are destroyed by oral route

Disadvantages Of Parenteral Preparations

1. Painful administration

2. Invasive