Formulation and Requirements of Parenteral Medicines

IV Route of Administration

Large proximal vein, rapid response, large or small volumes, aqueous solutions or emulsions

IM Route of Administration

Small volume of injection, used for control release, solutions or suspensions

SC Route of administration

Slower onset of action, very small volume, insulin, implants, suspensions, solutions

Advantages of Parenteral?

Immediate response Used for poor BA, Nausea and Vomiting unconscious, controlled by trained medical professionals, Localised effect, reduce dose and waste, range of release profile, TPN, correction of electrolytes

Disadvantages of Parenteral

Complicated manufacturing, Skill, Pain, infection, Allergy, difficult to reverse

Requirements for parenterals?

Sterile, free from endotoxins and pyrogens, limits to particle size cause embolism

Excipient considerations

Co-solvents, Surfactants, Buffers, Preservatives, Anti-oxidants, Tonicity agents

What are the colligative properties?

Vapour pressure lowering, boiling point elevation, freezing point depression, osmotic pressure

Extensive properties?

Dependent on size of sample

Intensive properties?

Dependent on the substance

Colligative properties definition?

dependent on the **ratio** of solute particles to solvent particles in the solution

What is Osmotic pressure?

the external pressure that must be applied to prevent the movement of solvent via osmosis

Osmolality

number of osmoles/kg of solvent

Osmolarity

number of osmoles/litre of solution

Hyperosmotic

Cell Crenation

Hypoosmotic

Haemolysis

Isosmoticity

there is no net movement of solvent the solutions are isosmotic

Isotonicity

biological membrane and remain in osmotic equilibrium, the solutions in respect to the membrane

How to adjust a hypotonic solution?

Dextrose or NaCl

How to adjust a hypertonic solution?

Needs to be injected in to large vein to dilute out

Possible complications of hypotonic solutions?

Haemolysis, water intoxication

Possible complications of hypertonic solutions?

RBC crenation, Hyperglycaemia, water and electrolyte loss, dehydration, coma

TPN administration?

Very slowly due to high number of particles, Central vein o peripheral vein