Tretinoin produced in the form of 2 drugs and cream – retinol palmitate (RP) and retinol acetate has long been used in the treatment of various skin diseases. Many remember how the oil droplets of the solution were placed on a piece of black bread, which was not so unpleasant in the mouth after ingestion. In recent years there have been changes (although they relate primarily to retinol palmitate solution in the oil 100,000 IU / ml) – solution manufactured on high-quality refined oil and has no unpleasant aftertaste, expanded indications for use of the drug and investigate its pharmacokinetics, dose adjusted
Interest dermatologists to vitamin A (contained in Tretinoin cream .05) increased because in large doses (at least 100,000 IU per day for adults) it shows previously unknown medicinal properties. In other words, at low doses Vitamin A acts differently than larger ones. Currently low doses of vitamin used in hypo -and vitamin A, while large – for the treatment of skin diseases as primary therapy.
Action retinol can be divided into local and general. Local effects on the skin includes the inhibition of keratinization and stimulate the synthesis of glycosaminoglycans, reducing sebum and increased proliferation of epithelial cells. Based on the local effects on the skin, it can be said that the use of retinol shown for any skin diseases associated with impaired keratinization, sebum and healing. The total effect is the stimulation of humoral and cellular immunity and macrophage function, and strengthening erythro myelopoietic activation epithelialization in the internal organs, improve dark adaptation, curbing the growth of small epithelial tumors.
In the last 2 decades after a series of research greatly expanded range of skin diseases in which vitamin A proved effective, and in many cases irreplaceable. These are:
Hereditary disorders of keratinization – normal and X – linked ichthyosis, ichthyosiform erythroderma, eythrokeratodermia palmar- plantar keratoderma, follicular keratosis and dyskeratosis, porokeratosis, congenital pachyonychia, brow ulerythema ;
multifactorial diseases – psoriasis, red hair lichen Deverzhi, atopic dermatitis ;
disease in violation of sebum – seborrhea, acne;
precancerous – Solar (solar ) keratoses, actinic lesions, xeroderma pigmentosum ;
erosive and ulcerative processes – bullous drug reaction, epidermolysis bullosa, skin ulcers of different origin, burns, uninfected wounds, family benign pemphigus Hailey – Hailey ;
Allergic – horn eczema, atopic eczema and in subacute and chronic stages.
Ingested Tretinoin cream .05 does not change and digested without additional preparation, which defines its high bioavailability. After sucking it to the liver where is stored in combination with a lipoprotein. In blood retinol is in a complex with retinol binding protein and prealbumin, recognized target cells ( epithelial cells of the skin, eyes, gastrointestinal tract ) by the receptors. Cell surface receptor proteins, vitamin A is released from the complexes with transport proteins and was transferred into the cell, where it binds to intracellular proteins. Its activity at the cellular level is modulated by two kinds of nuclear receptors that are capable of changing the expression of genes. Vitamin A has a dose-dependent effect on the proliferation of epithelial tissues quickly update activates the synthesis of glycoproteins in cells and stimulates their differentiation. Vitamin A has an effect on the cells of mesenchymal nature – fibroblasts, macrophages. It activates chemotaxis and phagocytic activity of neutrophilic leukocytes, release of lysosomal enzymes, stimulates the humoral immune response, the proliferation of T – lymphocyte subpopulations by changing the ratio of these cells in the predominance of the T -helper. The half-life of tretinoin – about a day. Vitamin excreted by the kidneys, where it is partially reabsorbed. Full excretion occurs in about a month.