Triacetin

METHOD OF PREPARATION

Note: It is necessary to determine the quantity of fatty acid base to use in this prescription prior to beginning the preparation of this formula (see IJPC 2000; 4(5): 371-373).

1. (Calculate the required quantity of each ingredient for the total amount to be prepared.

2. Accurately weigh and/or measure each ingredient.

3. Thoroughly pulverize the required number of sildenafil citrate tablets to obtain a fine powder. (A high-speed mill/coffee grinder works well.)

4. Mix the sildenafil citrate powder and the silica gel until uniform.

5. Heat the fatty acid base to about 40°C and remove from heat.

6. Add the powders and mix until uniform.

7. Pour into the required number of molds and allow to cool.

8. Trim, package and label.

PACKAGING

Package in tight, light-resistant containers.1

LABELING

Keep out of reach of children. Use only as directed.

STABILITY

A beyond-use date ot up to 6 months can be used for this preparation.1

USE

Sildenafil Vaginal Suppositories have been used to improve uterine artery flow and endometrial development in patients undergoing in vitro fertilization.

QUALITY CONTROL

Quality-control assessment can include weight, specific gravity, active-drug assay, color, texture of surface, appearance, feel, melting test, dissolution test, physical observation and physical stability.2

DISCUSSION

Sildenafil citrate (C^sub 22^H^sub 30^N^sub 6^O^sub 4^S.C^sub 6^H^sub 8^O^sub 7^, MW 666.70) occurs as a white to off-white crystalline powder that is soluble 3.5 mg/mL in water. It is formulated as blue, film-coated rounded-diamond-shaped tablets equivalent to 25 mg, 50 mg and 100 mg of sildenafil for oral administration. The tablets also contain microcrystalline cellulose, anhydrous dibasic calcium phosphate, croscarmellose sodium, magnesium stearate, hydroxypropyl methylcellulose, titanium dioxide, lactose, triacetin and FD&C Blue No. 2 aluminum lake. It is used as oral therapy for erectile dysfunction. Its mechanism involves the release of nitric oxide in the corpus cavernosum during sexual stimulation. It then activates the enzyme guanylate cyclase, which results in increased levels of cyclic guanosine monophosphate, producing smooth muscle relaxation of the corpus cavernosum and allowing inflow of blood.3

Silica gel, a form of silicon dioxide, is obtained by insolubilizing the dissolved silica in sodium silicate solution. If obtained by adding sodium silicate to a mineral acid, it is called silica gel; but if obtained by the destabilization of a solution of sodium silicate to yield very fine particles, it is called precipitated silica. Silica gel occurs as fine, white hygroscopic, odorless, amorphous powder with a usual particle size range between 2 and 10 µm. It is insoluble in water and alcohol and other organic solvents but is soluble in hot solutions of alkalai hydroxides. It is used as a desiccant, suspending agent and viscosity-increasing agent.4-5

Fattibase is a preblended suppository base that is used when a fatty-acid base is preferred, occurring as an opaque white solid. It contains triglycerides derived from palm, palm kernel and coconut oils, with self-emulsifying glyceryl monostearate and polyoxyl stearate as emulsifying and suspending agents. It is stable, has a bland taste and odor and a controlled melting range. It is widely used as a cocoa butter replacement for suppositories, lipsticks and lip balms. It has a melting point between 35° and 37°C and a specific gravity of 0.890.6

Cocoa butter and other fatty-acid type bases can be used for these suppositories. Different bases have different characteristics that must be considered.

REFERENCES

1. US Pharmacopeial Convention, Inc. United States Pharmacopeia 27-National Formulary22. Rockville, MD: US Pharmacopeial Convention, Inc.; 2004: 2345-2349.

2. Allen LV Jr. Standard operating procedure for performing physical quality assessment of suppositories, troches, lollipops and sticks. IJPC1999; 3(1): 56-57.

3. [No author listed.] Physicians' Desk Reference. 58th ed. Oradel, NJ: Medical Economics Inc.; 2004: 2662-2665.

4. Morefield E. Colloidal silicon dioxide. In: Kibbe AH, ed. Handbook of Pharmaceutical Excipients. 3rd ed. Washington, DC: American Pharmaceutical Association; 2000:143-145.

5. US Pharmacopeial Convention, Inc. United States Pharmacopeia 24-National Formulary 19. Rockville, MD; US Pharmacopeial Convention, Inc.; 1999:2214.

6. Fattibase [product information]. Minneapolis, MN: Paddock Laboratories, Inc.

Copyright International Journal of Pharmaceutical Compounding Mar/Apr 2005
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