Modified-release dosage

Types of Modified-Release Dosage

  • Mechanism that delivers a drug with a delay after administration (delayed-release dosage)
  • Mechanism that delivers a drug for a prolonged period of time (extended-release dosage)
  • Mechanism that delivers a drug to a specific target in the body (targeted-release dosage)
  • Sustained-release dosage forms maintain a constant drug concentration for a specific period of time with minimum side effects
  • Extended-release dosage consists of sustained-release (SR) or controlled-release (CR) dosage

Abbreviations and Considerations

  • No industry standard for abbreviations, leading to potential confusion and misreading
  • Clear handwriting is necessary, and putting the meaning in parentheses is advisable for drugs with multiple formulations
  • Examples of abbreviations include XR (extended-release), XL (extended-release), and SR (sustained-release)
  • Abbreviations should be used with caution to avoid prescribing errors
  • Lack of standardization in abbreviations can be a challenge in the medical field

Methods of Modified-Release Formulation

  • Most time-release drugs are formulated with the active ingredient embedded in an insoluble matrix
  • Some sustained-release formulations involve drug dissolution into the matrix, causing it to swell and form a gel
  • Micro-encapsulation is a technology used to produce complex dissolution profiles for sustained-release drugs
  • Considerations for sustained-release formulation include pharmacological activity, absorption, and biological half-life of the drug
  • Therapeutic index and dose dumping are factors to consider when developing time-release drugs

Diffusion and Dissolution Systems

  • Diffusion systems rate release is dependent on the rate at which the drug dissolves through a barrier, usually a polymer
  • Reservoir devices coat the drug with polymers to achieve sustained-release effects
  • Matrix devices form a matrix where the drug is dissolved or dispersed
  • Matrix devices cannot achieve zero-order release, but higher molecular weight molecules can be used
  • Factors such as food can affect the release rate of diffusion matrix devices
  • Dissolution systems require the drug to dissolve or disperse within a matrix
  • Reservoir devices have sustained-release effects when the polymer does not dissolve and allows drug release through diffusion
  • Matrix devices release the drug by undergoing diffusion, with the rate of dissolution determining the release rate
  • Matrix devices are easier to produce and protect from changes in the gastrointestinal tract, but release rate can be affected by factors like food.

Other Modified-Release Systems

  • Osmotic controlled-release oral delivery systems (OROS) use a semi-permeable outer membrane and small laser-drilled holes to release the drug.
  • Ion-exchange resins are cross-linked water-insoluble polymers that contain ionisable functional groups.
  • Floating systems float on gastric fluids due to their low density.
  • Bio-adhesive systems stick to mucus and are favorable for mouth-based interactions.
  • Matrix systems use a mixture of materials with the drug to slow down release.

Modified-release dosage Data Sources

Reference URL
Knowledge Graph