Guaifenesin

METHOD OF PREPARATION

Note: This preparation should be prepared in a laminar airflow hood in a deanroom or via isolation barrier technology by a validated aseptic compounding phannacist using strict aseptic technique. This is a high-risk 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. Mix the propylene glycol and dimethylacetamide with about 80 mL of sterile water for injection.

4. Dissolve the guaifenesin, dextrose and edetate disodium in this mixture.

5. Add sufficient sterile water for injection to volume and mix well

6. Filter through a sterile 0.20 -µm filter into sterile, single-use vials.

7. Package and label.

PACKAGING

Package in tight, light-resistant containers.1

LABELING

Keep out of reach of children. Use only as directed. Store in a refrigerator.

STABILITY

If not sterility tested: A beyond-use date of up to 24 hours at room temperature, up to 3 days at refrigerated temperature (2 to 8°C), or up to 45 days if frozen can be used for this preparation.1

Tf sterility tested: A beyond-use date of up to 14 days stored in a refrigerator can be used for this preparation.1

USE

Guaifenesin injection has been used as a skeletal muscle relaxant.

QUALITY CONTROL

Quality-control assessment can include weight/volume, physical observation, pH, specific gravity, osmolality, assay, color, clarity, particulate matter, sterility and pyrogenicity.2'3

DISCUSSION

Guaifenesin (C^sub 10^H^sub 14^O^sub 4^, MW 198.22) occurs as a white to slightly gray, crystalline powder that may have a slight characteristic odor. It is soluble in water (l g in 60 to 70 mL), alcohol and propylene glycol. It is sparingly soluble in glycerin. It has a melting range between 78 and 82°C. Guaifenesin for Injection USP contains not less than 90.0% and not more than 110.0% of the labeled amount of guaifcnesin. It contains not more than 0.0$ Endotoxin Units per milligram of gnaifenesin.1

Dextrose, anhydrous (C^sub 6^H^sub 12^O^sub 6^-H^sub 2^O, MW 180.6, anhydrous; MW 198.17, monohydrate) occurs as odorless, sweet-tasting, colorless crystals or as a white crystalline or granular powder. One gram of anhydrous dextrose is approximately equivalent to LIg of dextrose monohydratc.4

Propylene glycol (C^sub 3^H^sub 8^O^sub 2^, MW 765.09) occurs as a clear, colorless, viscous, practically odorless liquid with a sweet taste, somewhat resembling glycerin. It has a specifie gravity of 1.038 g/mL and is miscible with acetone, chloroform, 9S% ethanol, glycerin and water.5

Dimethylacetamide (C^sub 4^H^sub 9^NO, MW 87.12, N,N-dimethylacetainide, acetic acid dimethylamide, DMAC) occurs as an oily liquid with a weak, fishy odor and a density of 0.9429. It is miscible with water and most organic solvents. It has a melting point of0 -20°C, boiling point of 16$ to I67°C and refractive index of 1.437. It is used as a solvent in pharmaceuticals.6,7

Edetate disodium (C^sub 10^H^sub 14^N^sub 2^N^sub a2^O^sub 8^, MW 336.21, edetate disodium, edetic acid disodium, disodium ethylenediaminetctraacetate) occurs as an odorless white crystalline powder with a slightly acid taste. Tt is soluble l g in 11 mL of water, slightly soluble in 9S% ethanol and practically insoluble in chloroform and ether. The pH of a 1% w/v solution in carbon dioxide-free water is in the range of 4.3 to 4.7. it also occurs as the dihydrate (C^sub 10^H^sub 14^N^sub 2^N^sub a2^O^sub 8^.2H^sub 2^O, MW 372.2). The USP injection has a pH in the range of 6.5 to 7.S. It melts at 2S2°C with some decomposition.8,9

REFERENCES

1. United States Pharmacopeial Convention, Inc. United States Pharmacopeia 27-National Formulary22. Rockville, MD: US Pharmacopeial Convention, Inc.; 2004: 886-887,1950,2345-2349,2764.

2. Alien LV Jr. Standard operating procedure for paniculate testing for sterile products. /JPC1998; 2(1): 78.

3. Alien LV Jr. Standard operating procedure: Quality assessment for injectable solutions./JPC1999; 3(5): 406-407.

4. Day A. Dextrose. In: Rowe RC, Sheskey PJ, Weller PJ, eds. Handbook of Pharmaceutical Excipients. Washington, DC: American Pharmaceutical Association; 2003: 200-202.

5. 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.

6. [No author listed.) The Merck Index. 13th ed. Whitehouse Station, NJ: Merck & Co., Inc.; 2001: 568-569.

7. Ash M, Ash I. Handbook of Pharmaceutical Additives. 2nd ed. Endicott, NY: Synapse Information Resources, Inc.; 2002: 426-427.

8. Owen SC. Edetic acid. In: Rowe RC, Sheskey PJ, Weller PJ, eds. Handbook of Pharmaceutical Excipients. 4th ed. Washington, DC: American Pharmaceutical Association; 2003: 225-228.

9. Reynolds JE, ed. MAHTINDALE: The Extra Pharmacopeia. 30th ed. London: The Pharmaceutical Press; 1993: 681-682.

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