Triacetin

METHOD OF PREPARATION

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 tablets for the prescription. (A high-speed mill/coffee grinder works well.)

Cream

4. Add the propylene glycol and purified water to the sildenafil citrate powder, and form a smooth paste.

5. Incorporate into sufficient hydrophilic ointment (Dermabase, Vanicream) to final weight and mix well.

6. Package and label.

Gel

7. Mix the sildenafil and methylcellulose powders with the propylene glycol until uniform.

8. Warm the purified water to about 70°C and add to the powder-propylene glycol mixture.

9. Mix well and allow to congeal.

10.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 of 14 days can be used for this preparation when stored in a refrigerator.1

USE

Sildenafil cream and sildenafil gel have been used to improve uterine artery flow and endometrial development in patients undergoing in vitro fertilization.

QUALITY CONTROL

Quality-control assessment can include theoretical weight compared to actual weight, specific gravity, active-drug assay, color, clarity', texture-surface, texture-spatula spread, appearance, feel, rheological properties and physical observations.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.3

Propylene glycol (C^sub 3^H^sub 8^O^sub 7^, MW 76.09) occurs as a clear, colorless, viscous, practically odorless liquid with a sweet taste. It is miscible with acetone, chloroform, 95% ethanol, glycerin and water. It is not miscible with fixed oils or light mineral oil; it will, however, dissolve some essential oils.4

Methylcellulose (Methocel) is a practically odorless and tasteless, white to yellowish-white colored granule or powder that is widely used in both oral and topical formulations. It is hygroscopic and practically insoluble in acetone, ethanol, saturated salt solutions and hot water, but is soluble in glacial acetic acid.5

Purified water is water that is obtained by distillation, ion exchange, reverse osmosis or some other suitable process.6

Hydrophilic ointment is a water-washable oil-in-water emulsion base containing methylparaben, propylparaben, sodium lauryl sulfate, propylene glycol, stearyl alcohol, white petrolatum and purified water. It is miscible with water and aqueous.7-8

Dermabase is an unscented, washable, oil-in-water emulsion cream base. It contains purified water (about 45%), mineral oil, petrolatum, cetostearyl alcohol, propylene glycol, sodium lauryl sulfate, isopropyl palniitate, imidazolidinyl urea, methylparaben and propylparaben. It is a smooth, white, water-washable cream with a slight, pleasant odor.9

Vanicream is an oil-in-water emulsion base containing white petrolatum, cetearyl alcohol, ceteareth-20, sorbitol, propylene glycol, simethicone, glyceryl monostearate, polyethylene glycol monostearate and sorbic acid. It is free of dyes, perfume, lanolin, parabens and formaldehyde and is a stable and widely compatible cream.10

REFERENCES

1. US Pharmacopeial Convention, Inc. United States Pharmacopeia 27-National Formulary 22. Rockville, MD: US Pharmacopeial Convention, Inc.; 2004: 2345-2349.

2. Allen LV Jr. Standard operating procedure for performing physical quality assessment of ointments/creams/gels. IJPC1998; 2(4): 308-309.

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

4. Weller PJ. Propylene glycol. In: Rowe RC, Sheskey PJ, Weller PJ, eds. Handbook of Pharmaceutical Excipients. 4th ed. Washington, DC: American Pharmaceutical Association; 2003: 521-523.

5. Allen LV Jr, Luner PE. Methylcellulose. In: Rowe RC, Sheskey PJ, Weller PJ, eds. Handbook of Pharmaceutical Excipients. 4th ed. Washington, DC: American Pharmaceutical Association; 2003: 386-389.

6. Ellison A, Nash RA, Wilkin MJ. Water. In: Rowe RC, Sheskey PJ, Weller PJ, eds. Handbook of Pharmaceutical Excipients. 4th ed. Washington, DC: American Pharmaceutical Association; 2003:672-676.

7. Reilly WJ Jr. Pharmaceutical necessities. In: Gennaro AR, ed. Remington: The Science and Practice of Pharmacy. 19th ed. Easton, PA: Mack Publishing Company; 1995:1402.

8. Block LH. Medicated applications. In: Gennaro AR, ed. Remington: The Science and Practice of Pharmacy. 19th ed. Easton, PA: Mack Publishing Company; 1995:1586.

9. Dermabase [product information], Minneapolis, MN: Paddock Laboratories, Inc.

10.Vanicream [product information]. Rochester, MN: Pharmaceutical Specialties, Inc.

Copyright International Journal of Pharmaceutical Compounding Mar/Apr 2005
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