Oral Liquid Dosage Forms

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Oral Liquid Dosage Forms

• Physicochemical Characteristics
• Biological Characteristics
• Pharmaceutical Excipients
• Stability Problems of Oral Liquid Dosage Forms
• Biopharmaceutical Considerations

2
Physical Characteristics

• Appearance
• Solution
• Suspension
• Emulsion
• Physicochemical Characterization
• Molecular dispersed system
• Coarse dispersed system

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Physicochemical Characteristics

• Thermodynamically Stable
• Solution
• Thermodynamically Unstable
• Suspension
• Emulsion

When something is themodynamically stable, it
usually maintains its physical form.
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Physical Characteristics

• Solution
• Molecular dispersion Clear
• Pleasing to the eyes
• Clear
• Suspension
• Cloudy
• Visible change with time
• Emulsion
• Grease vs. smooth
• Viscous

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Physical Characteristics

• Solution
• Apparent taste
• Apparent smell
• Suspension
• Slower drug release
• Less taste or smell
• Emulsion
• Medium drug release rate
• Significant taste or smell

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Biological Characteristics

• Solution
• Rapid onset of action
• Compliance problem
• Suspension
• Slowest onset of action
• Sustained drug release
• Easier to dose drugs with bad taste/smell
• Emulsion
• Compliance problem
• Slower onset of action

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Pharmaceutical Excipients

• Excipients do not have pharmacological activities
  themselves and shall not enhance or diminish the
  pharmacological activities of the active species.
• Excipients are used in the manufacturing or the
  compounding process for the purposes of
• Maintaining the appearance
• Protecting the active species
• Disguising the unpleasant taste/smell
• Changing the dissolution rates of active species

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Pharmaceutical Excipients for Solution

• Maintaining the appearance
• Color
• Clarity
• Preservatives
• Surfactants
• Protecting the active species
• Buffers
• Antioxidants
• Disguising the unpleasant taste/smell
• Sugar
• Flavoring agents
• Changing the dissolution rates of active species
• Not applicable

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Pharmaceutical Excipients for Suspension

• Maintaining the appearance
• Color
• Preservatives
• Viscosity agents
• Flocculating agents
• Protecting the active species
• Buffer pH
• Antioxidant
• Less soluble particles
• Disguising the unpleasant taste/smell
• Sugar
• Flavoring agents
• Less soluble particles
• Changing the dissolution rates of active species
• Different salt forms
• Different particle size
• Different solvent compositions

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Flocculating Agents

• These are the most important agents to maintain a
  relatively constant particle size
• Themodynamic Unstable because
• Particle size uneven and too small
• Incorrect charges
• Density too high

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Flocculating Agents

• Mechanisms of Action
• Lower zeta potentials
• Electrolytes
• Ionic surfactants
• Build a gel-like network
• Polymer with proper cross-linker
• Viscosity modifications
• Polysaccharides Alginates Starchs
• Water soluble cellulose
• Hydrated silicates
• Synthetic polymers
• Colloidal solutions

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Types of Suspensions

• Deflocculating systems
• Minimize sedimentation with viscosity enhancers
• Flocculating systems
• Controllable and reversible sedimentation

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Pharmaceutical Excipients for Emulsion

• Maintaining the appearance
• Color
• Consistency
• Preservatives
• Protecting the active species
• Buffers
• Antioxidants
• Alternative distribution pattern
• Disguising the unpleasant taste/smell
• Sugar
• Flavoring agents
• Percent oil vs. water
• Changing the dissolution rates of active species
• Particle size of drug-containing dispersed phase

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Types of Emulsions

• Contain at least two immiscible liquid phases
  one called continuous phase, the other
  
  
  dispersed phase
• Oil (dispersed) in water (continuous) o/w
• Water in oil w/o
• Themodynamically unstable because of large
  surface tensions

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Emulsifying Agents

• Purpose Stable dosage form
• Functions
• Reduce surface tension
• Maintain particle size of the dispersed phase
• Types
• Ionic surfactants
• Nonionic surfactants
• Polysaccharide derivatives and others

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Stability Problems

• Solution
• Color change
• Loss of active component
• Clarity changes
• Suspensions
• Inability to resuspend the particles
• loss of significant amounts of active component
  is less likely because of the lower solubility.
• Emulsion
• Creaming
• Breaking (coalescence)

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Biopharmaceutical Considerations

• Solution
• Rapid release and faster onset than any other
  oral dosage forms
• Less variations
• Suspension
• Less smell and taste
• Longer dosing intervale
• Emulsion
• Not used often
• Used when it is absolutely necessary
• Many products for parenteral nutrition

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End of Oral Liquid Dosage Forms