Oral Solution Dosage Forms I Flashcards
1
Q
Properties
Pharmacutical solutions
A
- Rate of absorption can be limited by precipitation
- Chemical stability is lowest in solutions
2
Q
Definition
Pharmacutical solutions
A
- liquid preparations in which the therapeutic agent and the various excipients are dissolved in the chosen solvent system
3
Q
Solution
A
- Easily administered for individuals who have difficulty in swallowing
- The therapeutic agent is dissolved in the formulation and is therefore immediately available for absorption
- Reduces the chance of forming a precipitate
- Taste-masking of bitter therapeutic agents
4
Q
Disadvantages
A
- Unsuitable for therapeutic agents that are chemically unstable in the presence of water
- The poor solubility of certain therapeutic agents may prohibit their formulation as pharmaceutical solutions
- Expensive to ship and are bulky for the patient to carry (packaging might break)
5
Q
Co-solvents
A
- Ethanol
- Glycerol
- Proylene glycerol
6
Q
Examples of Excipients
A
- Anti oxidents
- Antimicrobial preservatives
- pH adjuster
- Viscosity enhancer
- Sweetners
7
Q
Water for non-parental
A
Purified by distilation, ion exchange reverse osmosis
8
Q
Water for injections
A
Futher purified to remove pyrogens
9
Q
Drug solubility
A
- Both the therapeutic agent and the excipients are required to be present in solution over the shelf-life of the formulated product
- Needs to be homogeneous
10
Q
High solubility
A
Readily incorporated into the vehicle and formulated as an oral solution
11
Q
Moderate solubility
A
- Solubility enhanced using co-solvents or by related methods (changing pH, salt conversion)
- Aqueous solubility is less than the requested concentration of therapeutic agent
12
Q
Low solubility
A
Formulated as an alternative-dosage form, e.g. a suspension
13
Q
Drug dissolution
A
- Removal of a molecule of the drug from the solid state
- Formation of a cavity within the solvent
- Accommodation of the drug molecule into the formed cavity
14
Q
Propeties that effect solubility
A
- Molecular weight - less soluble
- Particle size
- Solubility ∝ “1” /”melting point”
- Number of hydrogen bonds
- Hydrophilic groups (OH-, COO-, NH4+) >
- lipophilic - groups (methyl, ethyl)
- Crystalline/amorphous properties
15
Q
Factors effecting theraputic agents
A
- Vast majority of drugs are either weak acids or bases and therefore solubility are pH-dependent
- The solubility of acids and bases increases as the degree of ionisation increases