Pharmaceutical solutions Flashcards
What is the definition of solutions?
Liquid preparations containing chemical substances dissolved in a solvent or mixture of miscible solvents
What is the definition of solubility?
Maximal concentration of a solute that can dissolve in a solvent at a given temperature
How to read the solubility table?
The more parts (can be g or ml) I need, to dissolve a solute, the weaker the solubility
If I don’t need much solvent to dissolve a solute, the solubility is strong
What are the components of a solution?
- API
- Vehicle
- Co-solvent
- Preservatives
- Stabilizers
- Color and Flavor
Which properties should an active pharmaceutical ingredient (API) have?
-soluble and stable in a solvent (hydrolyzes if not stable)
-in case of low solubility -> co solvent is added
-to be absorbed it need to be unionized -> so there are mostly weak acid or bases
-flavors may be added in case of bitterness
Why are Solvents needed?
-to enhance the solubility of semi-polar drugs that mix water only to a degree -> so we add a solvent that mixes with water and the drug
Water, Ethanol, Propylene glycol, Isopropyl glycol, Glycerin, Acetone, Non-polar solvents
What is the difference between Bulk and packaged water?
-Bulk water: produced and used on the same site, don’t need to package
-Packaged water: produced somewhere and need to be packed and sterilized to prevent microbial growth
What are the types of Bulk water?
-Purified water: used as a diluent in the production of non-sterile products -> not pyrogen-free
-Pure steam: used for sterilizing porous (steam gets easier into pores) equipment, pretreated water is vaporized and distributed under pressure (e.g. autoclaving)
-Hemodialysis: used for dilution of hemodialysis concentrate (dialyzer: artificial kidney to clean the blood) -> not for injection
-Water for injection (WFI): sterilized and pyrogen free for sterile products
What are the types of packaged water?
all STERILE
-Sterile purified water: for preparation of sterile products and analytical applications
-Sterile water for injection (WFI): sterile products used for IV packaged for a single dose
-Bacteriostatic WFI: preparation for sterile products (IV) for multiple doses -> PRESERVATIVES and ANTIMICROBIALS added
-Sterile water for inhalation: used in inhalators, but not as strict as with water for IV
-Sterile water for irrigation: used to clean body cavities, not as strict as with water for IV
What are other solvents/vehicles?
other solvents may be added to water for semi-polar drugs
-Ethanol -> ETHYL ALCOHOL: preservative, mixes easily with water, for internal and external use
-Isopropyl alcohol: similar to ethyl alcohol but can’t be used internally, it is used as a disinfectant when more than 91%
-Glycerin (diol) and Propylene glycol (Triol) have multiple OH groups making them easy to mix with water,
Glycerin can be used as a preservative at high concentrations and tastes sweet, both for internal and external use
-Acetone: doesn’t have OH group, hence no H-bonding, but dipole-dipole interactions - CANNOT BE USED INTERNALLY
When are non-polar solvents used?
If the drug doesn’t interact with water at all (not often), the form of interaction is dipole moments
-f.e. fixed oils -> often used external preparations, internally in form of emulsions
Other excipients:
Preservatives, Flavor, Color, Sweetener, Buffers, Viscosity enhancer, anti oxidants
When are preservatives added?
-if alcohol with more than 10% or Glycerin in high concentration is added we don’t need preservatives
-examples: Benzoic acid, Sodium benzoate, Methylparaben and other parabens
What might be an issue when adding flavors and colors?
They are not very soluble, alcohol might be added as a cosolvent
-synthetic or natural oils
Which sweeteners cant be used for certain patients?
-Sucrose: not for diabetic patients
-Sorbitol: not for patients with irritable bowel syndrome (IBS), bc it causes GI distress
-Aspartame: phenylketonuria patients cant metabolize it