Cationic antiseptics are compounds characterized by the presence of positive charges in their chemical structure. This characteristic allows to these compounds to interact with the surface of some microorganism such us bacteria (Gram positive bacteria and Gram negative bacteria), fungi, protozoa and viruses, giving them an antibacterial property with a broad spectrum of action. This family includes many compounds such as quaternary ammonium salts (QACs) characterized by a single positive charge having therefore a slight antibacterial activity, and biguanides characterized by more positive charges. Scientific studies performed on this last compound better explained this mechanism of action, concluding that the higher the quantity of positive charges, the higher the antibacterial effect. Among the biguanides, PHMB (polyhexamethylene biguanide) has a chemical structure composed by a polymer made up of 10-12 monomers and has a higher number of positive charges with respect to other compounds of the same family; this characteristic gives it the ability to inhibit bacterial grow even in low concentration. Action mechanisms that allow biguanides to carry out their antiseptic activity involve plasma membrane bounds especially with anionic sites leading to destabilization of them and consequent pathogen multiplication inhibition, in low concentration. On the contrary in higher concentration there is a higher membrane fluidity and permeability with consequent rupture of structures that constitute pathogen microorganisms; spill of internal material and cell death. For its antibacterial characteristic PHMB is well known in clinical setting for various uses: it is used as disinfectant of oral cavity in mouthwashes, in contact lens or eye drops, in medicated gauze pads to clean skin lesions. In addition to these uses, clinical studies demonstrated that PHMB can be effective and safe also if used for infection of genital apparatus.
The female reproductive tract is provided with defense mechanisms that can protect it from attack by pathogenic microorganisms. These mechanisms are formed by the vaginal bacteria flora known as Doderlein Lactobacilli whose fundamental role is the maintenance of the physiological vaginal environment. Unfortunately, however, in certain stages of life or in the presence of certain special conditions the woman is more predisposed to attack by external microorganisms, preventing the vaginal defenses to carry out their task and maintain the natural physiological environment. In fact, the excessive use of douches or aggressive cleaning agents, the use of invasive contraceptives such as spirals, physical treatments such as laser therapy, cryotherapy or DTC, as well as bad habits such as smoking or even pregnancy or menopause, are factors that make the vaginal tract particularly subject to the onset of vaginal infections that if neglected can give rise to chronic forms, recurrent or more serious complications. Vaginal infections are inflammations which include: the nature of bacterial vaginosis, among which we find the Gardnerella, Gonorrhea and Chlamydia which represent the most frequent forms; fungal infections, including candidiasis; protozoa, such as Trichomoniasis; and viruses, wherein the Papilloma virus and Herpes viruses are the most widespread forms. Such vaginitis are a very common problem among women and are often characterized by unpleasant events such as itching, burning, increased vaginal secretions with bad smell. Biguanides can be used for the treatment of these problems in a safe and effective way. In fact, clinical studies conducted on women affected by vaginal infections, have shown that PHMB, substance pertaining to this class of compounds, allows on one hand to act on the membranes of these pathogens, preventing their growth and multiplication, and on the other hand does not interact with the natural vaginal bacterial flora, thus enabling its operation, helping to more quickly restore the vaginal physiological environment. Furthermore, in contrast to the therapeutic approaches employed in this type of infections, scientific studies have shown that the PHMB containing 10-12 monomers does not generate therapeutic resistance, phenomena of toxic effects and skin irritation. An application of this class of antibiotics in the form of vaginal solution or suppositories may be therefore useful for the treatment of vaginal tract infections of any origin and nature, allowing an effective resolution and avoiding the onset of secondary opportunistic infections or recurrent forms of these long-term micro-organisms. These types of infection may include not only the vaginal canal or cervicovaginal, but they often also involve the external genitalia of women and men. In fact very often these infections are also transmitted through sexual intercourse and a non treatment of both partners involves the uninterrupted passage of pathogens from one to another, that is why they are called pingpong infections. The woman thus also presents an inflammation on the external genitals and in this case we speak of vulvitis, while man can show infections in the area of the glans and/or foreskin characterized by redness, small warts, known as balanitis or balanoposthitis. Also in this case clinical studies have demonstrated the effectiveness of the use of biguanides in the treatment of disorders related to infections that affect the external genital tract with a view also to couple treatment.
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