Solutions 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
Otic
Ophthalmic
Topical
Solubility
Unsaturated sol’n - more solute dissolves
Saturated sol’n - no more solute dissolves
Superunsaturated sol’n - seed crystals added
Factors that affect solubility
- Temperature
- Physical property of solute and solvent
- Solubilities of weak acids and weak bases
- State of subdivision of the solute
- Physical agitation
Many of the important organic medicinal agents are either weak acids or weak bases, and their solubility depends on
PH of the solvent
Examples of weak bases
Alkaloids (atropine, codeine, morphine)
Antihistamines (diphenhydramine, promethazine)
Local anesthetics (cocaine, procaine, tetracaine)
Not very water soluble , but soluble in weak acids
Weak bases
Example of weak acids
Barbiturate drugs (phenobarbital)
Sulfonamides (sulfadiazine, sulfacetamide)
Form water-soluble salts in basic solution, and may separate from solution by lowering the pH
Weak acids
More soluble in organic solvents like ROH
Organic bases
Meaning of “Like dissolves like”
A solvent having a chemical structure most similar to that of the intended solute will be most likely to dissolve it.
Example under physical agitation
Calcium hydroxide solution, USP
Other characteristics of an ideal solvent includes
CLOVEC-PCC
Clarity
Low toxicity
Odor
Viscosity
Economy
Compatibility with other formulative ingredients
Palatability
Chemical inertness
Color
Used as a primary solvent for many organic compounds.
Alcohol, USP : Ethyl alcohol, Ethanol
Alcohol + Water mixture that dissolves both alcohol-soluble and water-soluble substances
Hydroalcoholic mixture
Content of alcohol USP by volume
94.9% to 96% ethanol (C2H5OH) by volume
Dehydrated alcohol is also known as
Absolute Alcohol
How many percent of ethanol does absolute alcohol have, and when it is used?
NLT 99.5% and is used when water free alcohol is desired
Alcohol is often preferred because of its miscibility with water and its ability to dissolve many water-insoluble ingredients,
including
Drug substances
Flavorants
Antimicrobial preservatives
Solvents for liquid preparations
ADRGIPP
Alcohol, USP: Ethyl alcohol, Ethanol
Diluted Alcohol, NF
Rubbing Alcohol
Glycerine, USP (Glycerol)
Isopropyl Rubbing Alcohol
Propylene Glycol
Purified water, USP
Percent of alcohol for children
Below 6y/old - 0.5%
6-12 y/old - 5%
Above 12 y/old 10%
Relative term of Solubility
Very Free Si Par Slight Very Slight Prac
Very soluble - <1
Freely soluble - 1 - 10
Soluble - 10 - 30
Sparingly soluble - 30 - 100
Slightly soluble - 100 - 1,000
Very slightly soluble - 1,000 - 10,000
Practically insoluble or insoluble - > 10,000
How to prepare Diluted Alcohol
Mixing equal volumes of Alcohol and Purified water
A useful hydroalcoholic solvent in various pharmaceutical processes and preparations.
Diluted Alcohol
RUBBING ALCOHOL
No notes
A clear syrupy liquid with a sweet taste. It is miscible with both water and alcohol. For internal preparations
Glycerin, USP (Glycerol)
Used externally as a rubefacient and soothing rub and as a vehicle for topical products.
Isopropyl Rubbing alcohol
It is a useful solvent with a wide range of applications and is frequently substituted for glycerin in modern pharmaceutical formulations.
Propylene Glycol
Purified water is obtained by
by distillation, ion exchange treatment, reverse osmosis or other suitable process.
Intended for use in the preparation of aqueous DF except those intended for parenteral administration
Purified water, USP
Has fewer solid impurities than ordinary drinking water? When evaporated to dryness, it must not yield more than how many percent of residue?
Purified water, USP
0.001%
Example of aqueous solution for parenteral administration
Water for Injection, USP
Bacteriostatic water for injection, USP
Sterile water for injection, USP
Most solutions intended for oral administration contains what? And why?
flavorants and colorants to make the
medication more attractive and palatable.
Example of a solution that has an unusually large dose, i.e. 200 mL
Benzydamine Hydrochloride (Difflam)
Anti-inflammatory drug (200mL)
Oral Solutions and Preparations for Oral Solution
Dry Mixtures for Solution
Oral Solutions
Oral Rehydration Solutions
What are the steps in reconstituting Amoxil® Suspension?
a. Tap the bottle until all powder flows freely
b. Add approximately 1/3 of the total amount of water for reconstitution (78 mL)
c. Shake vigorously to wet powder
d. Add remaining water
e. Shake again vigorously
Diarrhea is a normal physiologic body response to rid itself of a noxious or toxic substance, such as
Rotavirus & Escherichia coli
Use of ORS
allow the diarrhea to proceed and not to terminate it too quickly but promptly replace the lost fluid and electrolytes to prevent dehydration.
The loss of fluid during diarrhea is accompanied by depletion of
Sodium
Potassium
Bicarbonate ions
Severe loss of fluid during diarrhea can result to
Acidosis
Hyperpnea
Vomiting
Hypovolemic shock
This drug is usually effective in treatment of patients with mild volume depletion which occurs during diarrhea and/or vomiting.
Oral Rehydration Salts (ORS)
ORS contains what?
Sodium
Potassium
Chloride Citrate
Glucose
