Podcast Beta
Questions and Answers
What is a key advantage of the rectal administration of drugs?
What factors make rectal administration preferable over oral administration?
What is the typical length of a rectal suppository?
What is a primary characteristic of suppositories?
Signup and view all the answers
What historical materials were used to create suppositories?
Signup and view all the answers
What shapes are prevalent in vaginal suppositories?
Signup and view all the answers
Which of the following is a disadvantage of using suppositories?
Signup and view all the answers
What is the weight range typically for adult rectal suppositories?
Signup and view all the answers
What is the diameter of urethral suppositories?
Signup and view all the answers
Why might suppositories be preferred over oral medication?
Signup and view all the answers
Which of the following routes is generally preferred for drug administration?
Signup and view all the answers
Which patient group is particularly suitable for suppository administration?
Signup and view all the answers
In infants and children, how does the size of rectal suppositories compare to those for adults?
Signup and view all the answers
What are retention enemas primarily used for?
Signup and view all the answers
How do suppositories impact first-pass metabolism?
Signup and view all the answers
What percentage of the large intestine is comprised by the rectum?
Signup and view all the answers
What is often a reason for poor patient acceptance of suppositories?
Signup and view all the answers
How are urethral suppositories commonly referred to?
Signup and view all the answers
Which of the following dosage forms is NOT typically classified under rectal or vaginal preparations?
Signup and view all the answers
What is a significant advantage of vaginal administration compared to oral administration?
Signup and view all the answers
What disadvantage might occur with vaginal administration related to patient experience?
Signup and view all the answers
Which dosage form is specifically intended to dissolve or melt within the vagina?
Signup and view all the answers
What characteristic is NOT true about vaginal tablets?
Signup and view all the answers
Which attribute should be optimized for vaginal products to ensure effective drug delivery?
Signup and view all the answers
What is a main purpose of mucoadhesives in vaginal films?
Signup and view all the answers
What is a key feature of vaginal rings that differentiates them from other dosage forms?
Signup and view all the answers
Which of the following statements about vaginal semisolids is correct?
Signup and view all the answers
What is a possible benefit of using vaginal films in medication delivery?
Signup and view all the answers
What common component is found in the formulation of vaginal tablets?
Signup and view all the answers
What is the primary reason fatty bases are preferred for rectal suppositories?
Signup and view all the answers
Which of the following statements about cocoa butter is accurate?
Signup and view all the answers
What characteristic contributes to cocoa butter's unique properties when compared to semi-synthetic fatty bases?
Signup and view all the answers
What is a limitation of using cocoa butter in suppository formulations?
Signup and view all the answers
Why is it important for drugs to partition out of the suppository base and dissolve in the body?
Signup and view all the answers
What factor significantly affects the release rate of oil-soluble drugs in suppositories using fatty bases?
Signup and view all the answers
Which veins drain the inferior and middle rectum directly into systemic circulation?
Signup and view all the answers
What is the primary mechanism of drug absorption from the rectum?
Signup and view all the answers
If a drug is placed too high in the rectum, what metabolic process may it undergo?
Signup and view all the answers
What factor can influence drug absorption from rectal fluids?
Signup and view all the answers
How does osmotic effect impact the process of drug dissolution in the rectum?
Signup and view all the answers
What is the rectal pH in adults roughly around?
Signup and view all the answers
What happens to drugs after a suppository dissolves in the rectum?
Signup and view all the answers
Which factor does NOT affect drug absorption variability in the rectum?
Signup and view all the answers
What is a significant characteristic of the rectal epithelium compared to the upper gastrointestinal tract epithelium?
Signup and view all the answers
What might result from placing a suppository delivery system too high in the rectum?
Signup and view all the answers
The pre-blended suppository base, MBK is similar to what other base?
Signup and view all the answers
True or false. MBK exhibits polymorphism.
Signup and view all the answers
What are the MWs of PEG (a water soluble base) as a liquid?
Signup and view all the answers
Glycinerated gelatin suppositories contain what components?
Signup and view all the answers
Glycinerated gelatin suppositories are used to make what types of suppositories?
Signup and view all the answers
A low fat/oil solubility means what water solubility and choice of base?
Signup and view all the answers
A high fat/oil solubility means what water solubility and choice of base?
Signup and view all the answers
A low fat/oil solubility means was water solubility and choice of base?
Signup and view all the answers
Study Notes
Suppositories
- Solid dosage form for rectal, vaginal, or urethral use
- Contains active ingredient and a base that melts, softens, or dissolves in the body
- Provides local or regional action by distributing medication to tissues
- Can offer systemic action through absorption via rectal or vaginal mucous membranes
History of Suppositories
- Historically, suppositories were made using cloth, plants, wood, or other materials
- These materials were used plain or soaked in medication solutions
Drawbacks of Suppositories
- Strong feelings of aversion towards their use in some countries, notably the US and UK
- Significant inter- and intra-subject variation in absorption
- Challenges with large-scale manufacturing, including creating products with a long shelf life
- Not typically the first choice for drug administration
Advantages of Suppositories
- Safe and effective alternative for oral routes
- Enables sustained systemic and local drug delivery
- Allows for interruption of therapy by removal
- Novel polymers enable controlled drug release
- Convenient, non-messy, and non-staining
Enemas
- Liquid preparations administered rectally
- Retention enemas: retain medication
- Evacuation enemas: remove feces, used for constipation, impaction, and preparation for lower GI exams
Other Related Dosage Forms
- Inserted into the rectum or vagina for local or systemic action
- Examples: ointments, creams, aerosol foams, vaginal films
Uses of Suppositories
- Administration of drugs to infants, small children, debilitated patients, nauseated or vomiting patients, those unable or unwilling to take oral medication, and those unsuitable for parenteral routes.
Suppository Advantages and Disadvantages
Advantages
- Effective for drugs that degrade in the gastrointestinal tract (GIT)
- Minimizes first-pass metabolism
- Allows administration of large drug doses
- Offers some control over the duration of action
Disadvantages
- Poor patient acceptance and compliance
- Potential for messiness and leakage
- Slower absorption compared to intravenous or oral administration
- Upward migration from the site of administration can increase first-pass metabolism
Various Sizes and Shapes
Rectal Suppositories
- Conical or cylindrical
- Tapered or pointed on one end (bullet or torpedo shaped)
- Length: 1 to 5 inches
- Weight: 1 to 4 g, typically 2 g
- Smaller sizes and weights are used for infants and children
Vaginal Suppositories
- Also known as pessaries
- Globular, ovi-form, or cone-shaped
- Often use the same molds as rectal suppositories
Urethral Suppositories
- Also known as bougies
- Less common
- Slender, pencil-shaped, typically 3-6 mm in diameter
- Vary in length by gender: females 25-70 mm, males 50-125 mm
- Compounded using thin, long molds or oral dosing syringes
Rectal Route
- Preferred route is oral, but rectal administration is used when oral administration is impractical or infeasible.
- This might occur when a patient has nausea or vomiting, altered consciousness, is uncooperative, has restricted oral intake, or oral administration is not feasible.
Rectal Route Physiology
- The rectum is 15-20 cm long
- Contains the anal canal (4-5 cm).
- Highly vascularized rectal epithelium resembles upper GIT epithelium but lacks villi.
- Lower Rectum: Inferior and middle hemorrhoidal veins drain directly into systemic circulation.
- Upper Rectum: Superior hemorrhoidal vein drains directly into portal circulation.
Drug Absorption from Rectum
- Drugs absorbed from the lower rectum avoid first-pass hepatic metabolism due to lower and middle rectal vein drainage into systemic circulation.
- Drugs absorbed from the upper rectum are carried directly to the liver, undergoing first-pass metabolism, if placed too high.
- Patients should be instructed not to place the delivery system too high in the rectum unless directed by their physician.
Main Mechanism of Drug Absorption
- Passive diffusion
- Absorption is influenced by:
- Molecular weight of the drug
- Lipid solubility
- Degree of ionization
- Rectal fluid pH influences drug absorption
Rectal Fluid pH
- Adult rectal pH is roughly 7.2, but varies based on rectal contents.
- Independent of sex and age after puberty.
- Limited buffer capacity.
- Significantly lower than in children (9.6±0.9).
Factors Affecting Drug Absorption
- Diarrhea
- Disease States
- Large inter- and intra-subject variability in absorption
Drug Release from a Suppository
- Suppository dissolves or melts onto the mucous layer.
- Drug diffuses outward towards the rectal membranes.
- Drug absorption occurs through passive diffusion.
How Drugs Dissolve
- Small volume of rectal fluid (~3 mL) results in incomplete dissolution and requires additional water.
- Osmotic effect draws water out of rectal tissues, which can be uncomfortable for patients.
- Suspended drugs may lead to undesirable systemic side effects.
Vaginal Administration
Advantages
- Local or systemic drug administration
- Absorption is not affected by gastrointestinal, or GI disturbances.
- Venous drainage bypasses the hepatic portal vein, avoiding the first-pass effect.
- Convenience of self-administration, potentially releasing drug for weeks.
- Ease of self-administration.
- Painless application.
- Discreet use.
- Can effectively deliver lower doses of hormones.
Disadvantages
- Erratic and unpredictable systemic drug absorption, due to variations in vaginal epithelium thickness and pH.
- Leakage or slipping out may occur, soiling undergarments or clothing.
- Some patients are hesitant to use vaginal delivery systems.
Dosage Forms for Vaginal Administration
- Solids: tablets, suppositories (also known as pessaries, ovules, and inserts), films, inserts (rings).
- Semisolids: foams, ointments, creams, gels.
- solutions.
Vaginal Tablets
- Stable and less messy than ointments or creams.
- Intended to disintegrate in the vagina, releasing their contents.
- Commonly contain:
- Lactose as a filler
- Disintegrating agent (e.g., starch)
- Dispersing agent (e.g., polyvinylpyrrolidone)
- Tablet lubricant (e.g., magnesium stearate).
- Easy to manufacture and insert.
Vaginal Suppositories
- Stable and less messy than ointments or creams.
- Intended to dissolve or melt in the vagina, releasing their contents.
- Not as easy to manufacture as tablets, but easy to compound and insert.
Vaginal Films
- Paper-thin translucent films that dissolve quickly.
- Primarily provide local action.
- Most contain spermicides or other drugs like antibacterial agents.
- Mucoadhesives may improve retention time.
Vaginal Rings
- Flexible, circular polymeric delivery systems.
- Approximately 5.5 cm in diameter.
- Made of non-irritating materials like ethylene acetate copolymers, silicone, or poly(dimethylsiloxane).
- Non-messy to use.
- Release pre-determined amounts of drug per day over extended periods.
- Polymer is non-biodegradable.
- Reservoir system: drug is located in the center core, released via diffusion through the polymeric membrane coat.
- Release rate can be modified by modifying the thickness of the membrane coat or the diameter of the core.
Vaginal Semisolids
- Used for local vaginal action.
- Deliver spermicides, antibacterial drugs, hormones, and drugs for cervical ripening.
- Usually delivered with a plastic applicator.
- Result in high local drug concentrations for short durations.
- More viscous products remain in place longer.
- Bioadhesive or mucoadhesive gel formulations can extend contact time with epithelial surfaces.
Vaginal Semisolids - Disadvantages
- Messy to use.
- Can be uncomfortable for patients.
- Prone to leakage rather than remaining in place.
Vaginal Foams
- Similar advantages and disadvantages to other semisolids.
- Contain propellants to aid drug delivery.
- Pressure exerted by the propellant ensures the formulation fills the applicator space.
Dosage Form Design Considerations for Vaginal Products
- Product pH: Some products are formulated to match vaginal pH, which is crucial for drug solubility and stability.
- Microbial presence: Products should be free from microorganisms, yeast, and molds.
-
Product attributes after administration:
- Retention: Products should be retained long enough for drug distribution.
- Liquefaction: Products should disintegrate, dissolve, or melt within a reasonable timeframe.
- Distribution: Products should spread well throughout the vaginal cavity (e.g., high-density particles).
- The base should not bind to or interfere with drug release and absorption.
Suppository Bases
-
Classes of base:
- Fatty bases
- Water-soluble bases
- Choosing a base: Requires practical experience and cannot be solely guided by scientific data.
-
General guidelines:
- Fatty bases are preferred for rectal suppositories, providing soothing and emollient action, and are less irritating to rectal tissues.
- Water-soluble bases are used for vaginal and urethral suppositories, as oily material is less desirable in these scenarios due to the lack of sphincter muscles to prevent leakage.
-
Desired release rate:
- Oil-soluble drugs: slow release with fatty bases, moderate release with water-soluble bases.
- Water-soluble drugs: rapid release with fatty bases, moderate release with water-soluble bases.
Fatty or Oleaginous Bases
- Soothing and emollient action.
- Most used bases today are semi- or fully synthetic.
- Preferred for rectal suppositories due to less rectal tissue irritation.
- Less commonly used for vaginal and urethral suppositories, as oily material is less desirable.
-
Release drugs after melting in the rectum.
- The drug must partition out of the base and dissolve in sufficient aqueous media at the site of action.
- Absorption occurs after the drug is in solution.
Cocoa Butter (Theobroma Oil)
- Mixture of liquid triglycerides entrapped in a network of crystalline, solid triglycerides.
- Soothing and emollient action.
- Melts quickly at body temperature.
- Softens at 30°C and melts at 34°C.
- Must be stored in a refrigerator to avoid melting.
- Exhibits polymorphism, with the β form being the most stable.
- Should not be heated above 34°C.
Cocoa Butter - Disadvantages
- Fat-soluble drugs are trapped in the base and do not mix with body fluids, leading to potential trapping.
- Water-soluble drugs are quickly released, often leading to rapid absorption.
- Leakage from the body orifice, as it is immiscible with body fluids.
- Some drugs lower the melting point (e.g., chloral hydrate, phenol).
- Potential for polymorphism.
- Poor contraction on cooling, making removal from molds challenging, particularly in industrial settings.
- Low softening point.
- Chemical instability.
- Poor water-absorption power.
- Higher cost.
Semi-Synthetic Fatty Bases
- Also known as adeps solidus.
- Hard fats consisting of a mixture of triglycerides, diglycerides, and monoglycerides.
- Obtained from natural fatty acid esterification with glycerol or by natural fats transesterification.
- Characteristics:
- Melting point
- Hydroxyl value
- Saponification value
- Contain no additives.
Semi-Synthetic Fatty Bases - Comparison to Cocoa Butter
- Semi-synthetic: Most acids are saturated.
- Cocoa Butter: Contains considerable unsaturated oleic acid (primarily responsible for unique properties).
| Base | Melting Range | Acid Number (AN) | Hydroxyl Number (HN) | Iodine Number (IN) |
|---|---|---|---|---|
| Cocoa Butter | 31-34 °C | |||
| Semi-Synthetic |
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
Explore the world of suppositories, a unique dosage form for rectal, vaginal, or urethral use. This quiz delves into their history, advantages, drawbacks, and the challenges faced in manufacturing. Test your knowledge on how suppositories provide both local and systemic action.
