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Gepost op: 6 maart 2013

Deze crème breekt na de bereiding: Hydrochinon 4% Kojinezuur 4% (depigmenterend) Retinoine of tretioinezuur 0.05% Cetomacrogolcreme ad 100g


Van een Antwerpse specialist ontvingen wij een magistraal voorschrift met o.a. tretinoïnezuur, maar ook met kojinezuur. Dit laatste zou werkzaam zijn bij depigmentatie. Zonder kojinezuur lukt deze bereiding perfect maar na een tijdje breekt de crème. Er komt een waterachtige substantie uit de tube. Ik heb zelf al wat opzoekingswerk verricht en vandaag heb ik hem op volgende wijze gemaakt:

R/ Hydrochinon 4%
Retinoinezuur 0.05%
Butylhydroxytolueen 0.01% (als anti-oxidans voor de tretinoine)
Unguentum emulsificans cum aqua ad 100%

Antwoord

Dit is een goede bereidingsmethode. Hydrochinon is onverenigbaar met cetomacrogol. Er moet wel aandacht worden besteed aan de verdeling van retinoinezuur. Over het verwerken van retinoinezuur, een product dat niet zonder gevaar is, verscheen een artikel in het Farm. Tijdschr. van België.
Kojinezuur is weinig bekend in België voor het ogenblik. Als farmaceutische grondstof voor magistrale bereidingen is het niet op de markt. Enkel als chemische substantie. Zie ook "alternatief voor de grondstof".

 

Beschrijving

Kojic acid, 5-Hydroxy-2-hydroxymethyl-4-pyrone, 5-Hydroxy-2-(hydroxymethyl)-4H-pyran-4-one
CAS #: 501-30-4

Kojic acid (C6H6O4; 5-hydroxy-2-(hydroxymethyl)-4-pyrone) is a chelation agent produced by several species of fungi, especially Aspergillus oryzae, which has the Japanese common name koji. "Kojic acid is a by-product in the fermentation process of malting rice, for use in the manufacturing of sake, the Japanese rice wine." [1] It is a mild inhibitor of the formation of pigment in plant and animal tissues, and is used in food and cosmetics to preserve or change colors of substances. It is used on cut fruits to prevent oxidative browning, in seafood to preserve pink and red colors, and in cosmetics to lighten skin. Kojic acid also has antibacterial and antifungal properties.

Kojic acid is a more recent remedy for the treatment of pigment problems and age spots. Discovered in 1989, kojic acid has a similar effect as hydroquinone. Kojic acid is derived from a fungus, and studies have shown that it is effective as a lightening agent, inhibiting production of melanin (brown pigment).

Kojic acid (5-hydroxy-2-(hydroxymethyl)-4-pyrone), a fungal metabolic product, has increasingly been used as a skin-depigmenting agent in skin care products marketed in Japan since 1988. In order to determine its frequency of sensitization, during 1 year from October 1992 to September 1993, we performed patch testing with it in 220 female patients with suspected cosmetic-related contact dermatitis. Of the 220 patients, 8 used at least 1 skin care product containing kojic acid, 5 of whom reacted to kojic acid as well as to 1 or more their own products containing 1% kojic acid, but not to their other products not containing it, and 3 of whom were negative to kojic acid and all their own products. Patch testing with kojic acid in the remaining group of 212 patients, who had not previously used skin care products containing it, was negative without exception. The 5 kojic-acid-sensitive patients, aged 34 to 58 years, developed facial dermatitis 1-12 months after starting application of kojic-acid-containing products. Kojic acid is considered to have high sensitizing potential, as a comparatively high frequency of contact sensitivity was observed in patients using products containing it (5 out of 8).

Derivaat
Kojic Acid Dipalmitate has an excellent property of inhibiting the activity of tyrosinase present in the human skin so as to inhibit the melanin formation.It is more efficacious than straight kojic acid.Kojic Acid Dipalmitate can produce excellent effects in even toning the skin, fighting age spots, pregnancy marks, freckles as well as general skin pigmentation disorders of face and body. Unlike kojic acid, which often causes product stability problems such as color changes, Kojic Acid Dipalmitate offers excellent product stability without any color instability problems.

Features:

 

  1. Skin Lightening. Kojic Acid Dipalmitate offers more efficacious skin lightening effects. Compared with kojic acid, Kojic Acid Dipalmitate markedly enhances the inhibitory effects on tyrosinase activity, which prohibits the formation of melanin.
  2. Light and Heat Stability. Kojic Acid Dipalmitate is light and heat stable, while kojic acid tends to oxidize over time.
  3. pH Stability: Kojic Acid Dipalmitate is stable within a wide pH range of 4-9, which provides flexibility to formulators.
  4. Color Stability. Unlike kojic acid, Kojic Acid Dipalmitate does not turn brown or yellow over time for two reasons.First, kojic acid is not stable to light and heat, and tends to oxidize, which results in color change (often yellow or brown). Second, kojic acid tends to chelate with metal ions (e.g. iron), which often results in color change.On the contrary, Kojic Acid Dipalmitate is stable to pH, light, heat and oxidation, and does not complex with metal ions, which lead to color stability.
Applications: Skin care, sun care, skin whitening/lightening, treatment for pigmentary disorders such as age spots etc.

Solubility soluble in ware alcohol, mineral oil and esters.

Use level Skin care products: 1-7%

Alternatief voor de grondstof
Ik ontving een voorschrift waarop het volgende vermeld staat:
R/ Hydrochinon 4% in Neostrata Pigment Lightning Gel.
De gel bevat kojinezuur (2%), citroenzuur (1%), glycolzuur (3.2%), melkzuur (0.8%), gluconolactone (5%) en vitamine C (0,5%) De concentratie van vitamine C staat niet vermeld, ik weet dus niet of er voldoende Vit C aanwezig is, dat als antioxidans voor de hydrochinon kan dienen. Moet ik nog andere antioxidantia toevoegen?

Indien tretioinezuur niet voorkomt in de samenstelling denk ik dat de concentratie aan vitamine C volstaat en geen andere antioxydans moet worden toegevoegd. De volledige samernstelling van de gel is niet gekend en bijgevolg moet gelet worden op de verenigbaarheid met hydrochinon.

Aan deze crème wordt een houdbaarheid gegeven van 8 weken, bewaard bij KT.