Podcast
Questions and Answers
What is the main component of lubricant?
What is the main component of lubricant?
- Beeswax
- Surfactants
- Cocoa butter
- Aqueous solution of SLS (correct)
How many polymorphic forms does cocoa butter exist in?
How many polymorphic forms does cocoa butter exist in?
- 2
- 4 (correct)
- 3
- 5
What is the melting point of the stable beta polymorph of cocoa butter?
What is the melting point of the stable beta polymorph of cocoa butter?
- 28oC
- 17.3oC
- 34-35oC (correct)
- 20oC
What happens when cocoa butter is melted at about 36oC and allowed to solidify slowly?
What happens when cocoa butter is melted at about 36oC and allowed to solidify slowly?
What is the effect of adding certain drugs, such as volatile oils, to cocoa butter?
What is the effect of adding certain drugs, such as volatile oils, to cocoa butter?
What is added to cocoa butter to increase its absorptive capacity for water?
What is added to cocoa butter to increase its absorptive capacity for water?
What is the purpose of adding 3% to 5% of beeswax or spermaceti to cocoa butter?
What is the purpose of adding 3% to 5% of beeswax or spermaceti to cocoa butter?
What is a characteristic of cocoa butter depending on its source?
What is a characteristic of cocoa butter depending on its source?
What happens to a dissolved drug in a suppository?
What happens to a dissolved drug in a suppository?
What happens to a suspended drug in a suppository?
What happens to a suspended drug in a suppository?
What is a factor that affects the bioavailability of a drug in the rectum?
What is a factor that affects the bioavailability of a drug in the rectum?
What is typically the volume of available fluid in the rectum under physiological conditions?
What is typically the volume of available fluid in the rectum under physiological conditions?
What happens to the volume of available fluid in the rectum under non-physiological conditions?
What happens to the volume of available fluid in the rectum under non-physiological conditions?
What is the effect of increased fluid volume in the rectum on the absorption of slightly soluble drugs?
What is the effect of increased fluid volume in the rectum on the absorption of slightly soluble drugs?
What is the main composition of semi or fully synthetic triglycerides?
What is the main composition of semi or fully synthetic triglycerides?
What is the typical iodine number of synthetic fats?
What is the typical iodine number of synthetic fats?
What is the advantage of synthetic fats over cocoa butter in terms of melting range?
What is the advantage of synthetic fats over cocoa butter in terms of melting range?
What is the typical acid content of synthetic fats?
What is the typical acid content of synthetic fats?
What does a higher hydroxyl number indicate about a fatty base?
What does a higher hydroxyl number indicate about a fatty base?
What is the typical melting range of cocoa butter?
What is the typical melting range of cocoa butter?
What is the source of fatty bases?
What is the source of fatty bases?
What is an example of physical and chemical incompatibilities with additives in fatty bases?
What is an example of physical and chemical incompatibilities with additives in fatty bases?
What is the term for the amount of esters that can be hydrolyzed and turned into soap in fatty bases?
What is the term for the amount of esters that can be hydrolyzed and turned into soap in fatty bases?
What is the range of saponification values in fatty bases?
What is the range of saponification values in fatty bases?
What does the iodine value of fatty bases indicate?
What does the iodine value of fatty bases indicate?
What is the preferred iodine value in fatty bases?
What is the preferred iodine value in fatty bases?
What are the wetting and emulsifying properties of fatty bases used for?
What are the wetting and emulsifying properties of fatty bases used for?
What is the term for the temperature at which a fatty base is completely melted?
What is the term for the temperature at which a fatty base is completely melted?
What is the primary mechanism by which the abdominal organs exert pressure on a suppository in the rectum?
What is the primary mechanism by which the abdominal organs exert pressure on a suppository in the rectum?
What is the primary intention of a suppository?
What is the primary intention of a suppository?
What is the typical melting temperature of cocoa butter, a base used in suppository preparation?
What is the typical melting temperature of cocoa butter, a base used in suppository preparation?
What is the primary consideration for the pharmacist when formulating suppositories?
What is the primary consideration for the pharmacist when formulating suppositories?
What is the typical range of the weight of a suppository?
What is the typical range of the weight of a suppository?
What is the desirable property of a vehicle used in suppository preparation?
What is the desirable property of a vehicle used in suppository preparation?
What is the primary mechanism by which motility of the rectal muscle affects suppository absorption?
What is the primary mechanism by which motility of the rectal muscle affects suppository absorption?
What is the primary function of glycerinated gelatin as a base in suppository preparation?
What is the primary function of glycerinated gelatin as a base in suppository preparation?
Study Notes
Rectal Drug Absorption
- Drug dissolved in suppository diffuses out towards rectal membrane, followed by absorption
- Suspended drug leaves vehicle, precipitates or separates due to gravity and motility, then dissolves and diffuses before being absorbed
Physiological Factors Affecting Rectal Drug Absorption
- Properties of rectal fluid:
- Composition, viscosity, pH, and surface tension affect drug bioavailability
- Content of the rectum:
- Rectum is usually empty, but fecal contents from higher parts of the colon can affect absorption
- Enzymes:
- Rectum has no active esterases or peptidases, unlike the GIT
- Volume of available fluids:
- Typical volume of available fluid in the rectum is ~3 ml spread on a layer of ~100 µm thick
- Volume increases under non-physiological conditions, affecting absorption of slightly soluble drugs
- Motility of the rectal wall:
- Rectal wall exerts pressure on suppository, promoting spreading and absorption
Suppositories
- Intended to produce local action, systemic effect, or mechanical effect to facilitate emptying the lower bowel
- Prepared in various weights, sizes, and shapes according to intended use
- Drug is incorporated into a base, such as cocoa butter, glycerinated gelatin, or PEG
Formulation of Suppositories
- Pharmacist must consider shape, content, weight, and vehicle requirements
- Shape: cylindrical, conical, or torpedo
- Content: ranges from 0.1 to 40% w/w
- Weight: ranges from 1 to 4 grams
- Vehicle requirements:
- Melts or dissolves in the rectum and mixes with rectal fluid at ~34-36°C
- Melting range should be low enough to give rapid solidification and avoid drug precipitation
Fatty Bases
- Specifications:
- Origin and chemical composition (entirely natural, synthetic, or modified natural)
- Physical and chemical incompatibilities with additives (preservatives, antioxidants, emulsifiers)
- Melting range
- Solidification point
- Saponification value
- Iodine value
- Wetting and emulsifying properties
- Water number
- Acid value
Polymorphism of Cocoa Butter
- Exists in four polymorphic forms: α, β, β', and γ
- β polymorph is stable, while α, γ, and β' are unstable and revert to β
- To minimize formation of unstable forms, heat only briefly and below 36°C
Lowering of Melting Point
- Caused by addition of certain drugs (volatile oils, phenol, chloral hydrate)
- Can be raised back to desired range by adding beeswax or spermaceti (3-5% w/w)
Synthetic Fats vs Cocoa Butter
- Advantages of synthetic fats:
- No polymorphism
- Contain mainly saturated acids (iodine number < 3)
- Melting range is usually about 3°C higher
- Acid content is lower (mostly < 0.5)
- Hydroxyl number (5-30)
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Description
This quiz covers the process of drug absorption through suppositories, including the role of diffusion and physiological factors affecting rectal drug absorption.
