Several treatment modalities have been used to treat AV. Topical therapies include
antibiotics, azelaic acid, benzoyl peroxide, and retinoids. Systemic treatments include
antibiotics, hormonal therapy, and isotretinoin in addition to physical modalities as
chemical peeling .
Chemical peeling is a safe, efficacious, and cost-effective procedure for treating various
skin disorders and for enhancing cosmetic appearance. The principle of peeling involves
controlled chemical injury to the skin in order to promote it to rejuvenate, leading to
smoothening of the skin and improvement of its surface texture .
As patients become more concerned about the risks and side-effects of acne medications such
as antibiotics and isotretinoin, other options are needed .
Metformin is an oral antihyperglycemic agent often used to treat overweight type 2 diabetic
patients. It decreases hepatic glucose output and increases glucose utilization by muscles
and adipocytes by increasing insulin sensitivity .
Notably, metformin has been shown to suppress the mammalian target of rapamycin complex
(mTORC1) activity . mTORC, also known as the mechanistic target of rapamycin, is a central
cell growth regulating kinase that forms large molecular complexes in all eukaryotic cells.
Rapamycin is an mTORC1-specific inhibitor, which complexes with the FK506-binding 12 kDa
protein (FKBP12). Rapamycin analogs have been used clinically to treat a number of human
diseases, including cancer. A wide range of both extra- and intracellular signals, including
growth factors, nutrient status and stress conditions, have been shown to regulate mTORC1 to
control cell growth .
Hence, it is plausible that metformin through inhibition of mTORC1 improves acne as AV is one
of the mechanistic target of rapamycin complex 1 (mTORC1)-driven diseases. Moreover,
metformin has been suggested for the treatment of other insulin resistant-related skin
disorders such as hirsutism, hidradenitis suppurativa, and acanthosis nigricans .
In order to get a benefit from the anti-inflammatory effect of metformin on the skin, the
best option is to enhance its dermal effects, therefore, its side effects will be less
through the topical administration route .
Actually, by applying a topical form of this drug on acne spots, mTORC1 over activation in
skin cells can be inhibited which leads to disappearance of acne spots .
Salicylic acid (SA) is a safe and efficacious peeling agent for a number of dermatological
and cosmetic problems, including acne vulgaris .
SA peels soften the stratum corneum and cause skin shedding by loosening the intracellular
matrix and corneocyte connections which can lead to an improvement in non-inflammatory
comedones . Also, SA inhibits the arachidonic acid cascade leading to a decrease in
inflammatory lesions .
In our study, we chose the emulgel formulation as a topical metformin form to increase the
efficacy and absorption in treatment of AV. Emulgel used will be optimized for
biocompatibility, consistency and chemical compatibility with metformin.