Suppositories Lecture Flashcards
Define suppositories
Solid or semisolid dosage form intended for insertion into the body orifices where it melts, softens, or dissolves and exerts localized or systemic effects
What are the three types of suppositories?
Rectal, vaginal, urethral
What are the local action uses of suppositories?
Enables high local concentration
Faster onset of action
Relieve constipation, irritation, itching, inflammation, contraception, local anesthetics
What are the systemic action uses of suppositories?
Absorbed from mucous membranes of rectum and vagina
Avoids the first pass effect
Absorption is erratic and unpredictable
What are common suppositories for anti-hemorrhoidal suppositories?
Local anesthetics (benzocaine, lidocaine, pramoxine HCl)
Vasoconstrictors (epinephrine HCl, ephedrine sulfate, phenylephrine Hcl)
Astrigents (calamine, zinc oxide)
Soothing and protecting agent (lanolin–> physical barrier)
What are common suppositories for laxatives suppositories?
Glycerin suppositories (causes laxative action local irritation of the mucous membrane) Hyperosmotic laxative (draws water from surrounding tissue to the bowel)
Suppository for asthma?
Aminophylline
Suppository for NSAID?
Indomethacin
Suppository for nausea, tranqulizer?
Prochlorperazine
Suppository for nausea and vomiting?
ondansetron
Suppository for hypnotic?
chloral hydrate
Suppository for narcotic analgestic?
Oxymorphone HCl
Suppository for analgestic, antipyretic?
Asprin
Suppository for analgesic
Acetaminophen
What are advantages of suppositories?
Avoidance of oral and parenteral routes (protect drugs destroyed by the pH or enzymes of the stomach)
Patient who cant swallow
Unconscious patients
Heavy vomiting patients
Target delivery (minimized systemic toxicity, concentrated drug at the site of action)
What are the disadvantages of suppositories?
Messy to apply
Variation of absorption (colonic content, pH, placement to high, GI probs)
Irritation for mucous caused by drugs or bases
Leak or expelled after insertion
Cultural and religious factor
What are suppository characteristics?
Shape and size: vary to promote insertion and facilitate retention
Must release medicament: melt at body temp, dissolve (must absorb moisture and dissolve)
How do rectum suppositories absorb?
Melting or liquifaction
Must diffuse across the water and mucous layers adjacent to the epithelium
Drug delivered to the upper part of the rectum to be transported into the portal system
Avoid first pass: lower part of the rectum delivery
Rectum supp absorption depends on?
Physiological factors
Physiochemical nature of drug and its ability to traverse the physiologic barriers to absorption
Nature of the suppository base and its ability to release drugs
What physiological factors that affect drug absorption from the rectum?
Colonic content
Blood circulation
pH and lack of buffering capacity of the rectal fluids
What is colonic content?
When the rectum is void»_space;> full of fecal matter
Conditions such as diarrhea, colonic obstruction due to tumor or tissue dehydration
What does blood circulation mean?
Lower hemorhoidal vein of the colon receives teh absorbed drug and initiates its circulation throughout the body and thus bypasses the liver
Lymphatic circulation also assists
Any obstruction to blood supply to the rectum will affect the drug absorption from the rectum
What does rectal fluid have to do with absorption?
Do not generally undergo ionization because rectal fluid is essentially neutral in nature and have no buffer cpacity
Rectal pH may vary
Cocoa butter is immiscible with rectal fluid (retards the release of fat soluble)
Max bioavailability, use ionized form (salt), rather than unionized form.
What are the effects of solubility?
Lipophilic drugs
- slow release in oily base
- moderate release in water soluble/miscible base (drug dissolves slowly in aqueous compartment)
Water soluble drugs
- rapid release in oily base
- rapid to slow release in water soluble/miscible base
What are the effects of viscosity?
If viscous mass, drug released slowly
What are the effects of drug particle size?
Decrease PS, the greater chance for quick absorption
What are the shape and size of rectal suppositories?
Bullet, torpedo, little finger
Cylindrical, 32 mm long
- Weight: 2 grams (children: 1 g)
What is a example of suppositories?
Hydrocortisone (rectal suppository; treatment of inflammation; local)
Acetaminophen (rectal supp; treats analgestic, antipyretics; systemic)
What are the dispensing instructions for suppositories?
Remove paper foil before insertion
Advised to rub cocoa butter suppositories gently with fingers to provide lube
Glycerinated and PEG suppositories should be moistened with water
Bullet shape: point first
Shape, size, and uses of vaginal suppositories?
"Pessaries" Globular, oval or cone shaped Weigh 5 grams when cocoa butter is used Comes with an applicator Uses: infection in the urinary tract and as contraceptions
Example of vaginal suppository?
Clindamycin (treats bacterial vaginosis)
Dispensing instructions for vaginal suppositories?
Unwrap and place in applicator
Insert high into the vagina and press the plunger to release the meds
Use at bed time
Clean the applicator after use
Size of male urethral suppositories?
3-6 mm in diameter and about 140 mm long
About 4 grams weight when made of cocoa butter
Size of female urethral suppositories?
70mm long
About 2 grams when made of cocoa butter
What are urethral suppositories?
Pencil shaped suppositories to inserted into urethra
Whats an example of urethral suppositories?
MUSE (alprostadil)
Treats erectile dysfunctions
What is in the composition of suppositories?
Active ingredient
Suppository base
Additives (suspending, emulsifying, lubricating agents, and absorbance enhancers
What exactly is a suppository base?
Act as wehicle
Desirable properties: remain solid at room temperature by dissolve readily at body temp
- When melted, soft enough to pour and mix with drugs
- Stable
- Compatible
- Nontoxic, nonirritating
What are examples of a fatty base?
Cocoa butter Wecobee Witepsol Fattibase Synthetic fatty bases containing surfactants
What are examples of water-soluble and water miscible bases?
Glycerinated gelatin bases
Polyethylene glycol bases
What are some details about cocoa butter?
Yellowish solid that melts at 30-36 C
A mxiture of TGs of saturated and unsaturated FA
Polymorphs have lower melting points
- In case of overheating, cocoa butter may solidify as a lower melting polymorph
What is fattibase bases?
TGs from palm, palm kernel and coconut ouls with self emulsifying glyceryl monostearate and polyoxystearate
What is witepsol bases?
TGs of saturated FA C12-C18 with varied proportion of partial glycerides
What are Wecobee bases?
TGs derived from coconut oil
What bases do not exist in polymorphic form?
Fattibase, Vitepsol, Vecobee bases
They are cocoa butter substitutes
What are glycerinated gelatin bases?
Dissolving gelatin (20%) in glycerin (70%) and adding water (10%)
They do not melt but dissolve slowly
Hygroscopic, must be dispensed in tight containers
Water miscible base
What are polyethylene glycol bases?
Blends of various molecular weight PEG
Do not melt but dissolve in the body fluids
What are methods of preparation for suppositories?
Molding
Compression
Hand rolling and shaping
What is fusion molding?
"Pour molding" Melting the base Add drug Pour melt into molds Allow to cool and congeal Remove the hardened supp
What are suppository molds?
Small: produce 6-12 supps in a single operation
Industrial molds can produce hundreds of supp
What is compression?
Uses special suppository machine to compress paste-like mass into suppository
Suitable for heat-labile drugs
How does hand rolling work?
A finely powdered drug is mixed with the base in a mortar and pestle
Uniformly mixed paste is rolled into cylinders
Each small cylinder then rolled by hand until a supp shape is achieve
How to package a suppository?
Best to keep refridgerated
Cocoa butter : <35
PEG: high melting point
Container: tightly closed glass, individual wrapped foil
Environment:
- High humidity absorb water from atmosphere
- Low humidity: loose water to atmosphere (brittle)
