Investigating the Stability of Benzoyl Peroxide in Over-the-Counter Acne Medications

Abstract

One of the most commonly used ingredients in over-the-counter acne treatments in cream, gel, and wash form is benzoyl peroxide. It is an anti-bacterial agent that kills the bacterium (Propionibacterium acne) involved in the formation of acne. The formulation of these products is extremely difficult owing to the instability of benzoyl peroxide. Benzoyl peroxide is soluble in polyethylene glycol (PEG) and isopropyl myristate, but it is not stable in these solvents. Also, it is practically insoluble in water and only slightly soluble in ethanol but is very stable in the presence of these solvents. The stability of benzoyl peroxide in PEG or isopropyl myristate is increased upon addition of water or ethanol. Students take on the role of the process chemist and use peroxide strips to investigate the stability of benzoyl peroxide in an over-the-counter acne medication in solutions of water, ethanol, PEG, 50:50 ethanol:PEG, 50:50 water:PEG, isopropyl myristate, and 50:50 ethanol:isopropyl myristate.

Science and Business of Medicinal Chemistry: A “Bench-to-Bedside” Course for Nonmajors

“…For seven of the 15 weeks of the semester, students convened in the department’s organic teaching laboratory to perform a mix of wet and computational experiments directly linked to the concepts discussed in class . Three laboratory experiments previously published in this Journal − were adapted for nonscience students. In the first, students explored the effects of solvent formulation on the stability of over-the-counter, benzoyl peroxide acne medications .…”

“…Three laboratory experiments previously published in this Journal − were adapted for nonscience students. In the first, students explored the effects of solvent formulation on the stability of over-the-counter, benzoyl peroxide acne medications . In the second, the fatty acids in French fries were extracted and derivatized to determine their composition via gas chromatography .…”

“…27 In a subsequent laboratory session, students performed a protein database exercise to explore the noncovalent interactions governing the coordination of a peptide mimetic drug to HIV protease. 22,28 Chemistry in Context: Guest Speakers, Ethics and Social Justice Discussions, and a Field Trip Guest speakers served as a valuable resource to place medicinal chemistry in the context of industry and the public sphere. These were scheduled by contacting scientific collaborators, school alumnae, local papers, and government outreach offices.…”

“…This lecture was immediately followed by an activity where the students revisited their French fry laboratory data to write a mock science article for their school paper. 22 Toward the end of the semester, a lecture−lab period was used for a field trip to Gilead Science's pharmaceutical process facility. Field trips can be regarded as providing a vital "physical connection between classroom discussions and the real world".…”

“…62 Students then studied QUALYs 63 and pharmacoeconomics, applying what they learned toward a case study on Gardasil 64 vs the use of vinegar for cervical cancer treatment. 22,65 A case study on Merck and Mectizan 66 was used to explore philanthropic drug discovery and the Orphan Drug Act. 67…”