Effect Of Topical Drug Matrix On Growth Of Common Pathogenic Fungi Of Tinea Capitis

Objective: Tinea capitis is a superficial fungal infection caused by dermatophytes infecting hair and hair skin.dermatophytes are highly horny filamentous fungi.In the guidelines for the diagnosis and treatment of tinea capitis,it is clearly pointed out that dermatophytes are inhibited by long chain unsaturated fatty acids in sebum secretion.Water lipid membranes,composed of sebum and sweat and other substances,are a barrier against dermatophytes infection.The inhibitory ability of fatty acids to dermatophytes is related to its carbon chain length,unsaturation and double bond position.In the past experiments,the antifungal activity of fatty acid derivatives has been found one after another,but the experimental objects are yeast and Aspergillus as well as endophytic bacteria,and the inhibition of dermatophytes is very few.External medicine is the most important treatment for dermatology,and ointment cream is the most common external medicine.According to the general rules of Chinese Pharmacopoeia for ointment cream reagents and the statistics of OTC kinds of dermatology ointment matrix formula,these two kinds of external drugs contain a variety of fatty acid derivatives.Some of them have been proved to inhibit yeast and Aspergillus.Its effect on dermatophytes needs to be studied.The use of external drugs is not accurate compared with oral agents,and usually only the appropriate amount,small amount,less and other words vaguely describe the recommended dosage.In clinical practice,patients themselves explore the amount of medication,interdigital units and other recommended usage is less used.Too much or too little medication has a great impact on the therapeutic effect.The use of drugs per unit area is of great significance to the evaluation of drug effect.Methods: For the matrix composition that can be dissolved in water and or ethanol,the enzymatic turbidimetric method was used to determine the approximate minimum inhibitory concentration and to observe the effect of promoting or inhibiting the growth of dermatophytes.For the matrix of hydrophobic oil,the nutrient was added into the medium by ointment cream preparation process to form the medium,and the dermatophytes were cultured to observe whether it could inhibit the adhesion and colonization of dermatophytes.The average dosage per unit area was counted.The subjects were the adult patients who had confirmed the infection of dermatophytes with external antifungal agents..Results: Most of the antifungal ability of each component in the solution failed to reach the minimum inhibitory concentration,that is,completely inhibited the activity of dermatophytes,but some of them showed weak inhibitory effect at high concentration.Neutralizer triethanolamine with the solution of alkaline to low concentration of inhibition.The common preservative Nipagin ethyl ester has strong inhibitory activity against dermatophytes at low concentration.Monostearate glycolipid can promote the growth of dermatophytes at low concentration and inhibit at high concentration.The water-insoluble solid matrix may inhibit the growth of dermatophytes through its hydrophobicity and lipophilicity.The statistics of the amount of external medicine per unit area showed that most of the patients had the guidance of external medicine,which was lower than the recommended dosage on average,and had no statistical significance with age,sex,drug location and drug type.Conclusion: The matrix and some components of external drugs have the ability to inhibit fungi.When using these drugs,they may lead to misdiagnosis and misjudgment of the diagnosis of dermatophytes infection.Low-dose topical drugs may lead to infection of dermatophytes.The use of external drugs requires too much guidance from dermatologists.