Liquid Dosage Forms Flashcards
Give examples of cosolvents / water-miscible solvents and the example on using them
ethanol
propylene glycol
glycerin
sorbitol
Used in elixirs
Give examples of complex actions
- Iodine with KI2
- Iodine with PVP —> ex: 10% betadine
- Poorly sol drugs with beta-cyclodextrin
What are hydrotropic agents or salts used ?
- Sodium acetate —> ⬆️ sol of theophylline
- Sodium benzoate —> 30% —> ⬆️ sol caffeine/ benzoic acid / cholesterol
- Sodium salicylate —> ⬆️ sol of salicylic acid
- Sodium glycinate —> ⬆️ sol of theophylline
How to ⬆️ the solubilizing power of a surfactant ?
Electrolytes can increase the solubilizing power of surfactants by:
- reducing their cmc
- increasing the size of the resultant micelles.
What is the problem with using surfactants ?
a preservative may preferentially partitions into micelles
—> effective conc. is reduced.
Give examples on using surfactants
- Potassium oleate e.g. Cresol
Solubilize antiseptic substances
- Tween 80 e.g. kiddo pharmaton syrup
Solubilize oil soluble vitamins to allow adding water soluble vitamins
How to apply chemical modifications to increase sol?
- Formation of water-soluble derivatives —> by increasing the number of polar groups in a molecule by salt formation for example (e.g. chlorpromazine HCl)
- molecule may be modified to produce a new chemical entity or prodrug. (Prodrugs must revert to the parent molecule after administration) (e.g. Chloramphenicol sodium succinate)
When to use nonAq solutions?
- Diff to make comp aq solution of the ingredients at all storage temps
- Drug unstable in aq systems
- Depot therapy req e.g. IM injection of testosterone propionate oily solution.
What are the non Aq vehicles ?
- Fixed veg oils
- Monohydric alcohols
- Polyhydric alcohols
- Ethyl ether
What are the fixed vegetable oils used as nonAq solutions?
maize oil (corn oil)
Olive oil
cottonseed oil —> in vit A oral prep
castor oil —> in Triamcinolone ear drops
arachis (peanut) oil —> in Methyl salicylate liniment
sesame oil —> in testosterone enanthate inj. (Deltatestryl)
ethyl oleate ester —> testosterone propionate injection
MOC CASE
What are the monohydric alcohols? Have 1 OH
- Ethanol
• external application on unbroken skin.
• Its rapid evaporation after application imparts a cooling effect to the skin. e.g., salicylic acid lotion.
• Ethanol usually denatured (contains 5% methanol as a
denaturant, e.g., Industrial Methylated Spirit, IMS), which
is too toxic for internal use - Isopropyl alcohol
• It has similar properties as ethanol and used externally.
• Main advantage: - it is less likely to be abused than ethanol
- denaturation is not necessary.
What are the polyhydric alcohols ? ( 2 OH or more —> glycols )
- Propylene Glycol
A. Oral
B. Ear
C. Parenteral - Polyethylene Glycols (PEG)
Rarely used internally
Used: externally and parenterally
C. Glycerol
D. Sorbitol —> sweetening agent
E. Mannitol
What is ethyl ether ?
Used externally when mixed with alcohol 3:1 (v/v) —> to dissolve pyroxylin (a nitrocellulose product) in the preparation of collodions.
What are the flavoring and sweetening agents types?
A. SWEETENING AGENTS B. FLAVOURED SYRUPS C. AROMATIC OILS D. SYNTHETIC AROMATIC SUBSTANCES E. JUICES F. TINCTURES G. EXTRACTS
Give examples of sweeting agents
- Sucrose —> simple syrup BP
- Invert sugar —> invert syrup BP
- Sorbitol —> sorbitol solution 70% BP
- Saccharin sodium ( 10% solution )
Why sucrose is replaced by sorbitol ( 60% sweeter )?
- Avoid the risk of dental caries
2. For diabetic patients