Suppositories (Cut off for Exam 1)

Question 1

Suppositories

Answer 1

• Solid Dosage Forms intended for insertion into body cavities where they soften, dissolve, or melt and exert local or systemic effect
• Commonly used rectally and vaginally, though can also be sometimes used urethrally
• Various shapes and sizes, must insert into orifice without distension then retain its position for proper amount of time

Question 2

Local Action + Rectal

Answer 2

• Constipation - glycerin promotes laxation by local imitations of mucous membrane with dehydrating effects
• Pain, itching, hemorrhoid inflammation - anesthetics, vasoconstrictive astringents, emollients, and protective agents

Question 3

Local Action + Vaginal and Urethal

Answer 3

• Vaginal - contraception, antiseptics, antibacterials, antifungals
• Urethra - Antibacterial or local anesthetics in preparation for urethral exam

Question 4

Systemic Action

Answer 4

-Mucous membrane of rectum and vagina permits absorption of soluble drugs into blood stream.

Question 5

Suppository Advantages (5)

Answer 5

1. Avoid low pH of stomach
2. Avoids first pass metabolism
3. Avoids irritation of stomach
4. Effective route in treatment of patients with nausea
5. Allows for drug administration in patient who can’t or who refuse to swallow

Question 6

Absorption + Physiological Factors

Answer 6

• Colonic content - increased absorption in void colon
• Circulation route - abundant vascularization of submucosa region of rectum wall with blood and lymphatic vessels
• pH and lack of buffering - rectal fluids are neutral with no buffer capacity, drugs need to be unionized when inserted

Question 7

Absorption + Physicochemical Factors

Answer 7

• Lipid/Water Solubility - lipophilic drugs in fatty base has a decreased tendency to escape to surrounding aqueous fluid than hydrophilic drugs
• Particle size - smaller particles have increased rate of dissolution and absorption
• Nature of the bases - fatty and water soluble, must be able to melt to release drug and not inhibit its release, must not irritate membranes else it could initiate a bowel movement that could expel the suppository

Question 8

Suppository Bases

Answer 8

• Analogous to ointment bases
• *Must be solid at room temperature and soften/dissolve/melt at body temperature
• Fatty bases (Cocoa butter) - lipophilic drugs tend to remain in base while hydrophilic drugs release and absorb into the tissue
• Water soluble bases (Glycerated gelatin) - dissolve slowly in body fluids and release lipophilic drugs readily

Question 9

Calibration of Suppository Molds

Answer 9

• Individual molds hold a specific volume
• Differences in density between bases will result in differences in weights of suppositories with the same volume
• Pharmacists should calibrate the mold for the usual base (cocoa butter or PEG)

Question 10

Preparation of Suppositories

Answer 10

– Melting the base
– Incorporating any required medicaments
– Pouring the melt into molds
– Allowing the melt to cool and congeal into suppositories
– Removing the formed suppositories from the mold

Question 11

Fatty or Oleaginous Bases

Answer 11

• Most frequently employed (cocoa butter)
• Hydrogenated fatty acids of vegetable oils, EX: Palm kernel or cottonseed oils
• Glycerin with high weight fatty acids, EX: Palmitic or stearic acids
• Combinations used to obtain desired hardness for storage and transportation and desirable melting characteristics

Question 12

Cocoa Butter Problem

Answer 12

• Exhibits polymorphism: existence in several crystalline forms
• When heated too rapidly to a temp much higher than melting point and then quickly chilled, forms α crystals
• Must melt slowly and evenly (water bath) to avoid
  formation of the unstable crystals

Question 13

Alpha Crystals

Answer 13

• α crystals have a much lower melting point and may not solidify at room temp
• α crystals are a metastable form and slowly will revert back to β crystals, but this may take place over several days

Question 14

Water-soluble Bases

Answer 14

1. Glycerinated Gelatin

2. Polyethylene Glycol

Question 15

Glycerinated Gelatin

Answer 15

• Gelatin (20%), glycerin (70%), and solution or suspension of drug (10%)
• Most frequently used in the preparation of vaginal
  suppositories where prolonged local action is desired
• Protect from atmospheric moisture
• Should be moistened prior to insertion to avoid irritation

Question 16

Polyethylene Glycol

Answer 16

• Polymers of ethylene oxide and water with various chain lengths, molecular weights, and physical characteristics
• Vary from low weight PEGs that are clear, colorless liquids to high weights (> 1000) are wax-like, white solids with increasing hardness
• Mixed by fusion to achieve base with desired consistency and characteristics
• Do not melt at body temp, but slowly dissolve in body fluids

Question 17

Rectal Suppository Counseling

Answer 17

• If stored in refrigerator, allow to come to room temperature before insertion
• Rub cocoa butter suppositories gently with fingers to melt the surface and provide lubrication for insertion
• Glycerinated gelatin or PEG suppositories should be moistened with water to enhance lubrication and decrease irritation
• Remove all wrappings completely before insertion

Question 18

Vaginal Suppository Counseling

Answer 18

• Read all instructions
• Insert suppository high in the vagina with provided applicator
• Notify physician if burning, itching or signs of allergic reaction occur
• Because suppositories are commonly administered at bedtime and can be messy, instruct patient to use a sanitary napkin to protect nightwear and bed linens (if using an oleaginous base)

Question 19

Rectal Suppository Shapes/Sizes

Answer 19

• 32 mm (1.2 in) long, cylindrical and have one or both ends tapered
• Weight will depend on density of base and drug, but adult cocoa butter suppositories weight about 2 grams

Question 20

Vaginal Suppository Shapes/Sizes

Answer 20

• Usually globular, oviform, and cone shaped

- Weigh about 5 grams

Question 21

Urethral Suppositories Shapes/Sizes

Answer 21

• Slender, pencil shaped
• Male: 3 to 6 mm in diameter, 140 mm (5 in) long, and weigh 5g
• Female: half the length and weight