Long acting parenteral solutions Flashcards
what are long acting parenteral formulations
- long acting injections
- oily solutions
- oily suspensions
- aqueous suspensions
- microspheres
- liposomes - implants
why are long acting injectables used
- improved safety and efficacy
- improved patient compliance and outcomes
- cost reduction
- life cycle optimisation
- allows bolus delivery for some drugs that otherwise could require slow IV administration
what are the idealised characteristics of long acting injections
- controlled delivery over 1 week to 6 months from single injection
- biodegradable/biocompatible carrier materials
- easy to manufacture, store and administer product
- compatible with sensitive molecules
- compatible with conventional drugs
- low or high loading capability
- can deliver water soluble or water insoluble products
- provide proprietary protection
- low toxicity
- all generally recognised as safe excipients
- do not require drug modification
what are the benefits of long acting products and what are they used for
- treatment of resistant patients
- delivery of antipsychotics
- improving convenience of chronic care products
- improvement in safety profiles
- insulins
what are the types of sustained release dosage forms
- aqueous suspension injections
- oily injections
- implants
describe the use of a long acting antipsychotic injection
- deep IM injection which forms a depot
- drug released at fairly steady rate into blood, typically over several weeks
- 30% of patients with schizophrenia are treated with prolonged release injectable antipsychotic in UK
- may overcome poor adherence to oral antipsychotic regimens and help improve relapse rate
what are the disadvantages of long acting injections
- IM injection is uncomfortable and may produce injection site reactions
- dose titration may be more difficult than with immediate acting oral formulations
- adverse effects may persist until drug has been cleared from its depot site
name some antipsychotic LAI preparations
- haloperidol decanoate (FGA)
- olanzapine embonate
- both are every 2-4 weeks
what are the advantages of depot and other long acting antipsychotic injections from a healthcare professional perspective
- reduced necessity for tablets or capsules to be taken on daily basis
- reduced uncertainty about amount of medicine taken or not taken
- no influence of first pass metabolism so improved bioavailability
- more consistent delivery of antipsychotic with more stable plasma levels over time
- minimising side effects and variations in symptom control
what are the disadvantages of depot and other long acting antipsychotic injections from a healthcare professional perspective
- pain, erythema, swelling at injection site as well as nodule formation
- risk of damage to nerves, arteries or veins
- if side effects occur, they will be prolonged until plasma level falls
4.can take several weeks of plasma levels to reach steady state - the need to confirm efficacy and tolerability to the oral formulations of the non oil based LAI where required
- injection technique competence, assessment and training required
- dislike or phobia of needles
give examples of advantages of depot and other long acting antipsychotic injections from a patient perspective
- don’t have to remember to take medicine everyday
- may have fewer side effects with an injection as levels in blood don’t rise and fall as much
give examples of disadvantages of depot and other long acting antipsychotic injections from a patient perspective
- dislike of needles
- if you do develop side effects, they may persist for several weeks after injection is stopped
what are the different mechanisms used to give long action
- prodrug dissolved in oil
- polymeric microspheres
- poorly water soluble salt suspended in water
describe how ester groups are used for depot injectables (LAI)
- saturated fatty acid
- used to form prodrugs
- increases lipophilicity of drug
- used to decrease aqueous solubility of drugs
describe the properties of the risperidone long acting injection
- micrometer sized biodegradable poly microspheres which are loaded with risperidone and suspended in sterile saline
- diluent contains carmellose sodium, anhydrous citric acid, polysorbate 20 and sodium hydroxide