Excipients In Liquid Dosage Forms Flashcards
What are types of excipients in liquid dosage forms?
Solvents
Preservatives
Stabilizers/ anti-oxidant
Buffers
Isotonicity modifiers
Sweeteners
Flavors
Colors
What are the types of solvents?
Water
Ethyl alcohol
Glycerol
What are the advantages of water?
Cheap
Tasteless, odorless and colorless
Inert
Neutral
Physiologically compatible
Lack of toxicity
Available
Compatible with so many liquids
Can dissolve many drugs
What are disadvantages of water?
Support growth of microorganisms when contaminated
Favorable medium for many chemical reaction
A medium for all the degradation processes
May contain minerals
Dissolve sugars, proteins → encourage growth of microorganisms
What are the types of water?
Tap water (potable water)
Purified water
Water for injection
Bacteriostatic water for injection
What is tap water?
It contains minerals and microorganisms
Not permitted to be used for liquid dosage forms for dispensing of pharmaceutical dosage forms
Used in the preparation of purified water
Why tap water is not permitted to be used for liquid dosage forms for dispensing of pharmaceutical dosage forms?
Due to its possible bacterial contamination and the presence of dissolved salts that destroy the active ingredients or enhance their decomposition
What is the microbiological specification of tap water?
Contains not more than 500 cfu/ml
Absence of individual pathogenic microorganisms, escherichia coli, salmonella, staphylococcus aureus and pseudomonas aeruginosa per 100 ml
What is purified water?
Water free from minerals total solids < 10ppm
Prepared by distillation or ion exchange resins
Containers, closures and machine parts may be washed with portable water followed by suitably filtered purified water
Stored in stainless steel tanks or plastic tanks
What is the microbiological specification for purified water?
Contains not more than 100 cfu per ml and indicates absence of pathogenic microorganisms
What is water for injection?
Prepared from portable/purified water
Free from bacteria
Free from pyrogen
Free from minerals < 10ppm
Used for sterile products
WFI is sterile water may be found in containers of one liter
What is microbiological specification for water for injection ?
Contains not more than 10 cfu per 100 ml
Shall have an endotoxin level of not more than 0.25 eu/mi
What is bacteriostatic water for injection?
All characters of water for injection
Contains a bacteriostatic at specific concentration
Used for vials or multiple dose products
Volume must not exceed 30ml
What are advantages of ethyl alcohol
Kills microbes
Used to extract alkaloid and glycosides
More specific for dissolving materials
What are disadvantages of ethyl alcohol?
Volatile
Affects CNS, liver, git
Dissolves resins
Restricted use
What are advantages of glycerol?
Not volatile
Not toxic
Antimicrobial activity
Viscosity is high
Effect is better because duration is more
What are disadvantages of glycerol?
Hygroscopic
Dissolves gums, albumins, and tannins
What is the definition of preservatives?
Agents used to prevent the growth of microbes found into or allowed to inter in the container
What are examples of preservatives?
Benzoic acid 0.1 - 0.2%
Sodium benzoate 0.1 - 0.2%
Methyl parabens and propyl parabens 0.1 - 0.2%
Phenyl mercuric nitrate 0.002 - 0.01%
What are characteristics of preservatives?
Antimicrobial agents
Toxic
Required for multiple dose administration
What are properties of preservatives?
Must be used in the effective concentration
Must be safe, soluble and stable
Doesn’t interact with container or cover
Doesn’t interact with the drug or other ingredients in the formulation
What are the factors enhancing degradation?
Light
Heat
Catalyst
Drugs degradation occurs due to what?
Oxidation
Hydrolysis
Photo-degradation
What are the methods used to control oxidation?
Use dry powder
Avoid direct exposure to air
Use antioxidant (ascorbic acid and chelating agent)
What are the methods used to control hydrolysis?
Use dry powder followed by reconstitution just before use
Use solvents as glycerin, propylene glycol
Formulate at optimal pH at which least degradation occurs
Store at not more than 25°C
What are the methods used to avoid light?
Amber glass bottles
An opaque secondary package may also be used for this purpose
Storage in dark place
What are tonicity adjusting agents?
Substances that are added to adjust the tonicity of the solution dosage forms and make them isotonic solutions
Tonicity adjusting agents are added to what?
Ophthalmic preparations and parental dosage forms
Hypotonic and hypertonic solutions may cause what to the patient?
Harm and pain
What is the equation relating to the osmotic pressure of a solution to its concentration?
What is isotonic solution?
Solutions of the same osmotic pressure as the biological fluids
What is hypotonic solution?
Solutions that are more dilute
What is hypertonic solution?
Solutions that are more concentrated
What does the healthy body do In terms of isotonicity?
Maintains a delicate balance of water and electrolytes that are highly regulated by osmotic pressure and ion concentration
What are the units used for ionic concentration?
mEq/L
What are examples of tonicity adjusting agents?
Dextrose
Glycerin
Mannitol
Potassium chloride
Sodium chloride
The tonicity of parenteral fluids may be adjusted with what?
Sodium chloride or glucose (dextrose)
What is the usual range of sodium chloride and dextrose
Sodium chloride → 0,45 to 0.9%
Dextrose → 5-10 %
What are sweetening agents?
Provide sweetness and viscosity
What is the natural sweetener?
Sugar → sucrose
What concentration of sucrose does the syrup contain?
60 - 80 %
High concentration of sugar does what to microorganisms?
Inhibits the growth
When subjected to heat what happens to sucrose?
Hydrolyzed to glucose and fructose (invert sugar)
What is the difference between sucrose and invert sugar?
Invert sugar is sweeter
What is a disadvantage of natural sweeteners?
Can not be taken for diabetes and obesity
What are examples of other sweeteners?
Sorbitol
Glycerol
Propylene glycol
Methylcellulose (MC) hydroxyl ethyl cellulose (hc)
Synthetic sweeteners such as saccharine, sucralose, aspartame
What are the properties of MC and HC?
Not metabolized
Non-caloric
Viscosity enhancing agent
Provide syrup-like consistency to vehicles for medicine intended for diabetes and those on restricted diets
What are the properties of saccharin?
Synthetic
500 more sweeter than sucrose
What are properties of aspartame?
Artificial sweeting agent
Composed of 2 molecules, of aspartic acid
Decomposes in the presence of water (used in solid form only)
A flavoring agent is an excipient used to overcome what?
What are the properties of flavoring agents?
They are either soluble or insoluble in water
Flavors could be synthetic or naturally occurring agents
What are examples of flavoring agents?
What are aromatic waters?
They are saturated aqueous solutions of volatile oil substances and are used as solvents and flavoring agents
What are examples of aromatic waters?
Rose water
Caraway water
Cinnamon water
What are coloring agents used for?
Psychological, or identification purposes
What colors are used?
The ones approved by FDA
Why is tartrazine not used?
Due to allergy
Natural or synthetic are preferred?
Natural
What is a property that the colors should have?
Stability
