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42 Cards in this Set
- Front
- Back
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how are suppositories administered
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rectally (local or systemic)
vaginally (local or systemic) urethral (local) |
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requirements for suppository bases:
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solid at room temperature but melting at body temperature or dissolving in body fluids
non-irritating, chemically and physiologically inert compatible with drug stable during storage |
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types of bases:
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fatty or oleaginous bases
water-soluble bases miscellaneous bases |
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composition of fatty or oleaginous bases
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Composed of hydrophobic materials
cocoa butter semisynthetic triglycerides Mostly used base type for rectal suppositories |
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another name for cocoa butter
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Theobroma oil
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cocoa butter exists in several crystal forms
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true
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cocoa butter is immiscible with rectal fluids:
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represents additional lipophilic phase
the rate of release depends on the rate of melting and drug solubility |
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which form is used in cocoa butter supp?
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(beta) used because it softens at 30 °C & melts at 34-36 °C
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why can't cocoa butter supp be heated above 35oC
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because it converts to other crystal forms: (alpha) (Tm = 22 °C), (beta prime)’ (28 °C), (gamma) (18 °C)
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what compounds can decrease the melting point of cocoa butter
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phenol and chloral hydrate
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If needed, solidifying agents can be added to cocoa butter suppositories. what are they?
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cetyl ester wax (20%)
beeswax (4%) |
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Semisynthetic Triglycerides
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Typically, hydrogenated fats of vegetable oils
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how do semisynthetic triglycerides compare to cocoa butter?
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more expensive
do not exhibit polymorphism |
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some bases in semisynthetic triglycerides:
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Fattibase®: mixtures of triglycerides from palm, palm kernel, and coconut oils
Wecobee®: series of bases (marked as FS, M, R, and S) are made from triglycerides of coconut oil Witepsol®: mixtures of synthetic mono-, di-, and triglycerides of long chain fatty acids C12-C18 from vegetable oils |
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Water-soluble Bases
Dissolve in body fluids: |
do not need to melt at body temperature
simpler storage, especially in warmer climates (no refrigeration) |
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water-soluble Bases made of:
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Glycerinated gelatin and polyethylene glycols
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water-soluble Bases are less messy than fatty bases
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true
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water-soluble Bases dissolve and mix with body fluids
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true
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Drug release depends on the rate of dissolution of the suppository -->
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slower softening, dissolution and mixing with rectal fluids means slower drug release
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Glycerinated Gelatin
composed of: |
Granular gelatin (20%) + glycerin (70%) + drug solution (10%)
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glycerinated gelatin is:
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Translucent, resilient, gelatinous solids
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glycerinated gelatin
Hygroscopic material: |
stored protected from atmospheric moisture
may cause tissue irritation moisten with water before insertion |
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For extended shelf-life, preservatives are added to glycerinated gelatin. what are they?
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methylparaben
propylparaben |
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what are the common uses for glycerinated gelatin?
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Vaginal and urethral suppositories
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Polyethylene Glycols (PEGs)
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Polymers of ethylene oxide
Wide range of molecular weights ↑ MW, ↑viscosity and melting point Low:high molecular weight PEG ratio can be altered to prepare a base with a specific melting point and hardness Chemically stable, nonirritating, miscible with water and mucous secretions Incompatible with silver salts, quinine, aspirin, benzocaine, salicylic acid, camphor Suppositories should be moisten prior to use |
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PEGs mw and melting point
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300 = 15oC
600 = 20 to 25oC 1000 = 37 to 40oC 8000 = 60 to 63oC |
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Miscellaneous Bases
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Mixtures of fatty and water-soluble components
Self-emulsifying bases or preformed w/o emulsions Can absorb water Example: Polyoxyl 40 Stearate a mixture of the mono- and diesters of stearic acid and mixed polyethylene glycols (PEGs) PEGs have an average polymer length of about 40 oxyethylene units free diols are also present |
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Vaginal Delivery
uses: |
treatment of infections of the genitourinary tract
restore normal state of vaginal mucosa premenstrual syndrome |
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vaginal delivery
Treatment of Candida albicans infection: |
sulfanilamide
AVC suppositories (Novavax) |
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rectal delivery
local effects: |
pain, irritation, inflammation associated with hemorrhoids
laxatives |
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rectal delivery
systemic effects: |
antiemetic
analgesic sedative tranquilizer |
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Rectal Absorption I
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10-15 cm long
1-3 mL of fluid with low buffer capacity Rich in blood vessels Absorption area: 200-400 cm2 – 10,000 x smaller than small intestine No villi, only crypts |
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Rectal Absorption II
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see slide #15
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Rectal Absorption III
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see slide 16 and 17
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Factors Affecting Rectal Absorption
physiologic factors |
Position of the suppository in the rectum: part of drug may bypass hepatic pre-systemic metabolism
Presence of fecal matter Intestinal fluids: neutral pH and no effective buffering capacity |
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Factors Affecting Rectal Absorption
Physicochemical characteristics of drug and base |
Lipophilicity, amphiphilicity, cephalophilicity, and solubility
Nature of the base Size of drug particles |
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Advantages of Rectal Delivery
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Avoidance of enzymatic and pH effects in the stomach
Avoidance of stomach irritation by some drugs Appropriate route for patients with difficulty in swallowing (dysphagia) Appropriate route for vomiting patients Avoidance of the first-pass hepatic metabolism if the dose is positioned in the lower half of the rectum |
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Methods of Preparation I
Hand rolling: |
The oldest and simplest method
Suppository mass is formed into a ball in the palm of the hands, then rolled into a uniform cylinder. The cylinder is then cut into the appropriate number of pieces which are rolled on one end to produce a conical shape. |
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Methods of Preparation I
Compression method: |
Mass of suppository base and medicaments is forced into a special compression mold
Heat-labile drugs Special machines required |
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Methods of Preparation II
molding method |
Melting the suppository base
Dispersing or dissolving the drug Mixture poured into suppository mold Can be used to prepare suppositories prepared with all types of bases |
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Disposable plastic molds do not need any lubrication
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true
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Inserts
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Vaginal tablets
oviform usually administered using an applicator Capsules of gelatin: easier to produce less messy more stable |
