Comparison of Redermic, Rejuva-A and Combination of Both Redermic and Rejuva-A in Subjects With Signs of Aging

Facial skin aging is a complex and multifactorial process combining extrinsic and intrinsic factors. Major extrinsic factors include sun exposure and smoking while intrinsic factors are believed to be genetically programmed.

Changes in the dermis are responsible for many of the important clinical changes associated with skin aging. With age there is a decrease in the number of fibroblasts and a decrease in their ability to synthesize collagen which results in a decrease in collagen I and II. This is coupled with an increase in matrix metalloproteinases activity. Skin biopsies from elderly volunteers show changes in collagen bundles which become fragmented and disorganized as well as in elastin fibers which are decreased. Changes also occur in the epidermis including a decrease in epidermal thickness and a change in the morphology of keratinocytes of the basal layer. Clinically these changes result in skin atrophy, increased skin laxity, wrinkling, sagging, yellowness and changes in pigmentation.

Redermic is a cosmetic cream containing vitamin C and madecassoside. A preliminary 20 subject split face study has shown that this product was well tolerated and could improve signs of skin aging. To evaluate changes in skin aging this study used a clinical evaluation of the face, skin hydration, the fringe technique, skin biopsies and skin elasticity measurements. The investigators did not perform transepidermal water loss (TEWL), facial skin evaluation using a photonumeric guideline, evaluation of photoaging by panel of blinded dermatologists or skin replica evaluations. There is no data on the combination of Redermic with tretinoin or on the safety and efficacy of Redermic as compared to topical tretinoin.

Rejuva is a cream currently approved by Health Canada for the treatment of photodamaged skin. It contains 0.025% tretinoin one of the most widely studied topical product for skin aging. Studies have shown that topical tretinoin increases collagen synthesis and epidermal thickness thereby improving the appearance of skin aging. The efficacy of Rejuva combined with another topical cosmetic cream such as Redermic in the treatment of skin aging is unknown.

The main objective of this single-blind study was to assess efficacy of the anti aging effect and the tolerance of Redermic alone compared to Rejuva-A™ (0.025% tretinoin) alone or in combination with Rejuva-A™ (0.025% tretinoin).

One hundred and twenty (120) subjects with signs of skin aging participated in this single-blind study to evaluate the efficacy and tolerance of Redermic versus Rejuva-A™ (0.025% tretinoin) and Redermic in combination with Rejuva-A™ (0.025% tretinoin). Subjects were randomized (1:1:1) in three groups of forty (40), and were asked to apply study product to the face (except to eyelids, nostrils and other mucous membranes) for 24 weeks.

Inclusion criteria

• Subjects are female, between 45 and 55 years of age.
• Females of childbearing potential have had a negative urine pregnancy test prior to randomization.
• Subjects are willing to use adequate contraceptive method or are surgically sterile (including tubal ligation), post-menopausal, abstinent or with a same-sex partner. Adequate means of contraception include; intra-uterine device (IUD) in use for 30 days before Day 0, barrier methods and spermicide in use at least 14 days before Day 0 or oral contraceptive in use for at least 30 days before Day 0.
• Subjects are willing to avoid prolonged exposure to UV radiation for the duration of the study.
• Subjects are capable of giving written informed consent.
• Subjects have changes associated with facial skin aging/photodamaged skin.

Exclusion criteria

• Subjects are male.
• Subjects are pregnant or lactating.
• Subjects have a known allergy to Redermic, Rejuva-A™ or to any component of the tested products.
• Subjects have made use of tretinoin, adapalene, tazarotene or other topical medications for the treatment of facial skin aging during the 12 weeks preceding Day 0.
• Subjects have applied topical alpha hydroxyl acids within 28 days of Day 0.
• Subjects have used or plan to use systemic corticosteroids within 28 days of Day 0 or during the study.
• Subjects have made use of a non-medication topical product directed at improving skin aging during the 28 days preceding Day 0.
• Subjects have a hypersensitivity to any retinoids.
• Subjects have a history of alcohol or drug abuse in the past year.
• Subjects are participating in another interventional study.
• Subjects have had a previous intense pulsed light treatment to the face.
• Subjects have had a previous laser treatment to the face directed at improving skin aging.
• Subjects have the presence of skin diseases such as psoriasis or dermatitis on the face that could interfere with study evaluations.
• Planned or unavoidable exposure to intense ultraviolet (UV) radiation during the study (such as sun tanning salons, vacations in a sunny climate or outdoor worker).
• Subjects have had a botulinum toxin A injection treatment on the face within 2 years of Day 0 or plan to receive this treatment during the study.
• Subjects have had a filler injection (collagen, hyaluronic acid, etc..) on the face within 2 years of Day 0 or plan to receive this treatment during the study.