Marketing consultant Dermatologist, Joshi Hospital Maharashtra Medical Basis, Jehangir Hospital, Apollo Group, Pune, Maharashtra, India
Summary
INTRODUCTION
Vitamin C (Vit. C) is without doubt one of the naturally occurring antioxidants in nature.[1,2] Most crops and animals are in a position to synthesise Vit. C in vivo from glucose. People and sure different vertebrates lack the enzyme L-glucono-gamma lactone oxidase required for in vivo synthesis of Vit. C;[3] therefore, they need to purchase it from pure sources similar to citrus fruits, inexperienced leafy greens, strawberries, papaya and broccoli.[3,4] The phrase “Ascorbus” means no Scurvy. Historically, Vit. C-rich meals like lemons have been carried by sailors on lengthy journeys to keep away from Scurvy, a illness of bleeding gums. In 1937, Dr. Albert Szent Goyrgi was awarded the Nobel Prize for his work in isolating the Vit. C molecule from pink peppers and figuring out its position in Scurvy.[4]
L-ascorbic acid (LAA) is the chemically energetic type of Vit. C. In nature, Vit. C is present in equal components as LAA and D-ascorbic acid. These are basically isomeric molecules and are mutually interchangeable.[4] Nevertheless, solely LAA is biologically energetic and thus helpful in medical observe.[2] The absorption of Vit. C within the intestine is proscribed by an energetic transport mechanism and therefore a finite quantity of the drug is absorbed regardless of excessive oral dosage.[3] Moreover, bioavailability of Vit. C within the pores and skin is insufficient when it’s administered orally.[1,2] Using topical ascorbic acid is subsequently favored within the observe of dermatology.[5]
BIOCHEMISTRY OF VITAMIN C
Vit. C has a 5-hydrocarbon ring just like that of glucose. With an connected hydrogen ion, LAA turns into a weak sugar acid, just like different alfa hydroxy acids utilized in dermatology. With a metallic ion, it varieties a mineral ascorbate. There’s a marked curiosity in synthesis of physiologically energetic and chemically secure ascorbate molecules as LAA is unstable in nature, particularly when uncovered to mild.
MECHANISM OF ACTION OF VITAMIN C WITH REFERENCE TO DERMATOLOGY
TOPICAL FORMULATIONS OF VITAMIN C – “vitamin c cosmetics”
Vit. C is on the market out there as a wide range of lotions, serum and transdermal patches. Of those, solely the serum comprises energetic Vit. C in an nearly colorless type. It’s unstable and, on publicity to mild, will get oxidized to Dehydro Ascorbic Acid (DHAA), which imparts a yellow coloration. The steadiness of Vit. C is managed by sustaining a pH of lower than 3.5. At this pH, the ionic cost on the molecule is eliminated and it’s transported nicely throughout the stratum corneum.[3,5,9]
From a medical viewpoint, it is very important observe that the efficacy of the Vit. C serum is proportional to the focus, however solely as much as 20%.[3] The half-life within the pores and skin after attaining most focus is 4 days. A persistent reservoir of Vit. C is essential for ample photoprotection, and could be achieved by common 8-hourly purposes.[1,5] As UV mild lowers tissue Vit. C ranges, topical Vit. C is finest used after publicity to UV mild and never prior.[1–3] A mixture of tyrosine, zinc and Vit. C has been proven to extend the bioavailability of Vit. C 20-times vis-à-vis utilizing simply Vit. C.[2]
Quite a lot of lotions with Vit. C derivatives can be found out there. As a dermatologist, it is very important know that not all preparations are physiologically efficient. Some should not delivered into the dermis in an ample amount, whereas others don’t chemically convert to the biologically energetic type of Vit. C within the pores and skin.[1,2,4]
Magnesium ascorbyl phosphate (MAP) is essentially the most secure and most popular ascorbyl ester. This lipophilic molecule is well absorbed into the pores and skin, and the rate-limiting step for absorption is its launch from the automobile, and never the speed of diffusion throughout the stratum corneum as one would possibly suppose. MAP has a hydrating impact on the pores and skin and reduces transepidermal water loss. It is usually a free radical scavenger that’s photoprotective and will increase collagen manufacturing beneath laboratory check situations.[1,3] Different helpful secure esterified derivatives are:
ADVERSE REACTIONS OF TOPICAL VITAMIN C
Topical Vit. C is basically protected to make use of each day for lengthy durations. It could actually safely be used at the side of different widespread topical anti-ageing brokers similar to sunscreens, tretinoin, different antioxidants and alfa hydroxy acids similar to glycolic acid. Minor opposed reactions embrace a yellowish discoloration of the pores and skin, hypopigmented hair and marking of garments, which happen resulting from oxidative modifications of Vit. C. As soon as utilized, Vit. C can’t be absolutely washed or wiped off the pores and skin. Hardly ever, stinging, erythema and dryness are noticed after use of topical Vit. C. These can simply be handled utilizing a moisturiser. Care should be taken whereas making use of Vit. C across the eyes.[1,2]
Urticaria and erythema multiforme, following the usage of topical Vit. C, have been documented.[1] The poisonous doses of Vit. C that result in mobile apoptosis beneath laboratory situations are 100-200-times the each day really useful dose, giving Vit. C a really excessive security profile.[1]
FUTURE DEVELOPMENTS
As Vit. C is hydrophilic, there’s a marked curiosity to seek out strategies of environment friendly transepidermal supply of the secure energetic compound. If antioxidants might be delivered in excessive focus by the stratum corneum barrier, then a dermal reservoir of protecting antioxidant might be elevated and thus photoprotection could be enhanced.[5] As acknowledged earlier, the usage of secure lipophilic esterified derivatives of Vit. C is being explored for the aim.[5,8,10–13] In depth analysis is underway to research microspheres, nanoparticles and multilayered microemulsions for graded topical supply. Trials have been carried out with Vit. C and Vit. E in the identical multilayered emulsions collectively.[6] Each electroporation and iontophoresis have been used to reinforce penetration of Vit. C into the dermis.[11,14,15] Utility of Vit. C to the handled pores and skin floor after microdermabrasion and CO2 or Er-Yag resurfacing will increase the transepidermal penetration of Vit. C 20-times.[2,16] It has additionally been noticed that Vit. C is an efficient priming agent and a post-operative agent for the prevention of erythema following laser resurfacing. People who smoke have been discovered to have low Vit. C ranges within the dermis, akin to UV-damaged pores and skin. Smoking-related pores and skin ageing is one other space the place efficacy of Vit. C is being explored. One other very helpful utility of Vit. C could also be striae, the place a research has proven that each day utility of Vit. C mixed with 20% glycolic acid over 3 months can considerably enhance striae.[9]
“vitamin c cosmetics”