Minoxidil 10%, Finasteride 0.1%, Biotin 0.2%, and Caffeine Citrate 0.05% Hydroalcoholic Solution

US Pharm. 2020;45(6):48-CV3.

Method of Preparation: Calculate the required quantity of each ingredient for the total amount to be prepared. Accurately weigh or measure each ingredient. Mix the propylene glycol, ethyl alcohol (40 mL), and purified water. Add the minoxidil while stirring. Slowly and dropwise, add the sulfuric acid 20% solution to a pH between 4.5 and 5.0. Add the biotin, finasteride, and caffeine citrate; mix well. Add sufficient ethyl alcohol to final volume and mix well. Package and label.

Use: This preparation has been studied and used in the treatment of male androgenetic alopecia.¹

Packaging: Package in tight, light-resistant containers.

Labeling: Keep out of reach of children. For external use only. Discard after ____ [time period].

Stability: A beyond-use date of up to 30 days may be used for this preparation.²

Quality Control: Quality-control assessment can include weight/volume, pH, specific gravity, active drug assay, color, rheologic properties/pourability, physical observation, and physical stability (discoloration, foreign materials, gas formation, mold growth).³

Discussion: Minoxidil (Loniten, Rogaine, C₉H₁₅N₅O, MW 209.25) is used as an antihypertensive and as a topical hair growth stimulant. Minoxidil occurs as a white or off-white, odorless, crystalline solid that is slightly soluble in water to the extent of approximately 2 mg/mL; is readily soluble in propylene glycol or ethanol; and is almost insoluble in acetone or ethyl acetate. It melts at 248°C to 268°C with decomposition. Minoxidil is commercially available as a 2% topical solution and a 5% foam, with different presentations.

The 2% minoxidil topical solution contains minoxidil in a solution composed of alcohol (63%), propylene glycol (20%), and water. It is a clear, colorless to slightly yellow-colored solution. The yellow color will not alter its effectiveness. The 5% foam contains minoxidil along with SD alcohol 40B, purified water, butylated hydroxytoluene, lactic acid, citric acid anhydrous, glycerol anhydrous, cetyl alcohol, stearyl alcohol, polysorbate 60, and propellant. The foam is creamy in appearance. The commercial foam is available in a container with 60 g of product.⁴

Finasteride (Propecia, Proscar, C₂₃H₃₆N₂O₂, MW 372.54) occurs as a white to off-white, crystalline solid that melts at about 257°C and is freely soluble in alcohol and very slightly soluble in water. It is a 5-alpha reductase inhibitor indicated for the treatment of male pattern hair loss (androgenetic alopecia) in men only and is a medication mainly used to treat an enlarged prostate or hair loss in men. Women and children should not use this medication.⁵

Biotin (Bioepiderm, coenzyme R, vitamin B₇, vitamin H, W factor, C₁₀H₁₆N₂O₃S, MW 244.31) occurs as a practically white, crystalline powder that is very slightly soluble in water and alcohol. Biotin, a vitamin, is also commonly used to treat for hair loss, brittle nails, and other conditions.⁶

Caffeine citrate (Cafcit, C₁₄H₁₈N₄O₉, MW 386.31) occurs as a white, odorless powder with a slightly bitter, acid taste. It is soluble 1 g in approximately 4 mL warm water.⁷

Propylene glycol (C₃H₈O₂) occurs as a clear, colorless, viscous, practically odorless liquid with a sweet taste and somewhat resembles glycerin. It has a specific gravity of 1.038 g/mL and is miscible with acetone, chloroform, 95% ethanol, glycerin, and water.⁸

Ethyl alcohol (alcohol, ethanol, grain alcohol, C₂H₅OH, MW 46.07) is a clear, colorless, mobile, and volatile liquid with a slight, characteristic odor and a burning taste. It is miscible with chloroform, glycerin, and water.⁹

REFERENCES

1. Marotta JC, Patel G, Carvalho M, Blakeney S. Clinical efficacy of a topical compounded formulation in male androgenetic alopecia: minoxidil 10%, finasteride 0.1%, biotin 0.2%, and caffeine citrate 0.05% hydroalcoholic solution. IJPC. 2020;24(1):69-76.
2. U.S. Pharmacopeia/National Formulary [current revision]. Rockville, MD: U.S. Pharmacopeial Convention, Inc; May 2020.
3. Allen LV Jr. Summary of quality-control testing for sterile and nonsterile compounded preparations, part 1: physical and chemical testing. IJPC. 2019;23(3):211-216.
4. Drugs.com. Minoxidil (topical). www.drugs.com/ppa/minoxidil-topical.html. Accessed May 6, 2020.
5. WebMD. Finasteride. www.webmd.com/drugs/2/drug-1548-167/finasteride-oral/finasteride-oral/details. Accessed May 6, 2020.
6. WebMD. Biotin. www.webmd.com/vitamins/ai/ingredientmono-313/biotin. Accessed May 6, 2020.
7. Caffeine, citrated. In: Allen LV Jr. Remington: The Science and Practice of Pharmacy. 22nd ed. London, England: Pharmaceutical Press; 2013:1281-1283.
8. Driver S. Propylene glycol. In: Sheskey PJ, Cook WG, Cable CG, eds. Handbook of Pharmaceutical Excipients. 8th ed. London, England: Pharmaceutical Press; 2017:795-798.
9. Fenton ME. Ethanol. In: Sheskey PJ, Cook WG, Cable CG, eds. Handbook of Pharmaceutical Excipients. 8th ed. London, England: Pharmaceutical Press; 2017:356-359.

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