Quiz Flashcards
liquid preparations that contain one or more chemical substances dissolved in a
suitable solvent or mixture of mutually miscible solvents
Solutions
Solutions may be classified as:
• Oral solution
• Otic solution
• Ophthalmic solution
• Topical solution
Solutions, because of their composition or use,
may be classified as other pharmaceutical dosage
forms such as:
• Syrups
• Elixirs
• Spirits
• Tinctures
Certain solutions are prepared to be sterile and pyrogen- free and intended for parenteral administration are
classified as ___________
injections
When molecules interact, attractive and repulsive forces are in
effect
• When the attractive and repulsive are equal, the potential energy
between two molecules is ________ and the system is most _________
• When a solute dissolves, the substance’s intermolecular forces of attraction must be overcome by forces of attraction between
solute and solvent molecules
• This entails breaking the solute-solute forces and the solvent-
solvent forces to achieve the solute-solvent attraction.
-minimum
-stable
The solubility of an agent in a particular solvent
indicates the ________________to which a
solution may be prepared with that agent and that solvent
• When a solvent at a given temperature has dissolved all of the solute it can, it is said to be _____________.
The solubility of an agent in a particular solvent indicates the maximum concentration to which a solution may be prepared with that agent and that
solvent
• When a solvent at a given temperature has dissolved all of the solute it can, it is said to be saturated.
FACTORS AFFECTING SOLUBILITY
- Temperature
- Chemical and Physical properties of the solute and the
solvent - Pressure
- pH of the solution
- State of the subdivision of the solute
- Physical agitation applied to the solution as it dissolves
Chemicals with positive heat of solution
• The kind that absorbs heat when dissolved
• It results to an increase solubility with an increase in
temperature
Chemicals with positive heat of solution
• The kind that releases heat when dissolved
• It results to a decreased solubility with an increase in
temperature
Chemicals with negative heat of solution
Effects of Physicochemical Properties (pressure
and temperature) of the solute and solvent
The solubility of a “pure” chemical substance at a given temperature and pressure is _____
constant
State of subdivision of the solute
(Particle size)
• The “_____” the powder, the greater the
surface area that comes in contact with the
solvent.
• Therefore, the more rapid the dissolving
process.
finer
The greater the agitation, the more _________ solvent passes over the drug
• Therefore, the faster the formulation of a
solution
unsaturated
Effect of pH of the Solution
• Many important organic medicinal agents are either “weak acids” or “weak bases.”
• Drugs as weak bases are not very water soluble, but are _______________
• Drugs as weak acids form ______________
• These drugs may separate from the solution by lowering the pH of the solvent system
Effect of pH of the Solution
• Many important organic medicinal agents are either “weak acids” or “weak bases.”
• Drugs as weak bases are not very water soluble, but are soluble in dilute solutions of acids
• Drugs as weak acids form water soluble salts in basic solutions
• These drugs may separate from the solution by lowering the pH of the solvent system
Techniques to hasten dissolution
• Application of heat
• Reduction of particle size of the solute
• Use of a solubilizing agent
• Subject the ingredients to vigorous agitation
Some solvents for liquid preparations
• Alcohol, USP
• Diluted alcohol, NF
• Rubbing alcohol
• Glycerin, USP
• Isopropyl rubbing alcohol
• Propylene glycol, USP
• Purified water, USP
• The most useful solvent, next to water
• 94.9% to 96% C2H5OH v/v
• Miscible with water and has the ability to dissolve many water-insoluble ingredients (flavorant, preservatives)
• With preservative effect
• is frequently used with other solvents such as glycols and glycerin, to reduce the amount of alcohol required
Alcohol, USP
Alcohol, USP
• However, concern has been expressed over the undesired pharmacologic and potential toxic effects
of alcohol.
• Children under 6 years of age— alcohol limit ____
• 6-12 years of age ——alcohol limit ____
• Over 12 years of age and adults—alcohol limit ______
Alcohol, USP
• However, concern has been expressed over the
undesired pharmacologic and potential toxic effects
of alcohol.
• Children under 6 years of age— alcohol limit 0.5%
• 6-12 years of age —–alcohol limit 5%
• Over 12 years of age and adults—alcohol limit 10%
• Contains equal volumes of Alcohol, USP and
Purified Water, USP
• 49% concentration
• A useful hydroalcoholic solvent
Diluted Alcohol, NF
• Contains about 70% Ethanol v/v
• Volatile and flammable, should be stored in tight containers, remote from fire
• Used externally as rubefacient, soothing rub,germicide (for instruments), skin cleanser (prior to injection), vehicle in topical preparations
Rubbing Alcohol
Rubbing Alcohol
• It is also used as a vehicle for topical preparations
• The product is volatile and flammable and should be stored in __________ remote from fire
tight containers
• Glycerol, CH2-OH-CHOH-CH2OH
• Clear, viscous syrupy liquid with sweet taste
• Miscible to both water and alcohol
• Comparable to alcohol, as solvent
• Solutes are slowly soluble (requires heating)
• Preservatives, stabilizer, auxiliary solvent with water and
alcohol
• Used extensively in internal preparations
Glycerin, USP
• 70% v/v isopropyl alcohol
• Commercially available as 91%
• External Uses: rubefacient, soothing rub, vehicle for topical products
• Commonly employed by diabetic patients in preparing needles and syringes for hypodermic injections of insulin
• Skin disinfection of diabetic patients
Isopropyl Rubbing Alcohol