Polyhexamethylene biguanide hydrochloride (PHMB)-properties and application of an antiseptic agent. A narrative review

Dual function surfactants for pharmaceutical formulations: The case of surface active and antibacterial 1-tolyl alkyl biguanide derivatives

One interesting field of research in the view of developing novel surfactants for pharmaceutical and cosmetic applications is the design of amphiphiles showing further bioactive properties in addition to those commonly displayed by surface-active compounds. We propose here the chemical synthesis, and characterization of 1-o-tolyl alkyl biguanide derivatives, having different lengths of the hydrocarbon chain (C3, C6, and C10), and showing surface active and antibacterial/disinfectant activities toward both Gram-positive and Gram-negative bacteria. Both surface active properties in terms of critical micelle concentration (CMC) and surface tension at CMC (γCMC), as well as the antimicrobial activity in terms of minimum inhibitory concentrations (MICs), were strongly dependent on the length of the hydrocarbon chain. Particularly, the C6 and C10 derivatives have a good ability to decrease surface tension (γCMC <40 mN/m) at low concentrations (CMC < 12 mM) and a satisfactory antibacterial effect (MIC values between 0.230 and 0.012 mM against S. aureus strains and between 0.910 and 0.190 against P.aeruginosa strains). Interestingly, these compounds showed a disinfectant activity at the tested concentrations that was comparable to that of the reference compound chlorhexidine digluconate. All these results support the possible use of these amphiphilic compounds as antibacterial agents and disinfectants in pharmaceutical or cosmetic formulations.

Polyhexamethylene Biguanide Reduces High-Risk Human Papilloma Virus Viral Load in Cervical Cell Samples Derived from ThinPrep Pap Test

Human papilloma virus (HPV) infection and its progression still represent a great medical challenge worldwide. Clinical evidence has demonstrated the beneficial effects of polyhexamethylene biguanide (PHMB) on HPV clinical manifestations; however, evidence of the effect of this molecule on HPV viral load is still lacking. In this in vitro study, 13 ThinPrep Papanicolaou (Pap) tests were treated with a PHMB solution (0.10 g/100 mL) for 2 h. We observed no cytological changes but a significant reduction in the viral load of high-risk (HR) HPV after PHMB treatment, also revealing a dose-dependent antiviral effect. In addition, by stratifying the obtained results according to HR-HPV genotype, we observed a significant reduction in the viral load of HPV 16, P2 (56, 59, 66), 31, and P3 (35, 39, 68) and a strong decrease in the viral load of HPV 45, 52, and P1 (33, 58). Overall, 85% of the analyzed cervical cell samples exhibited an improvement in HPV viral load after PHMB exposure, while only 15% remain unchanged. For the first time, the data from this pilot study support the activity of PHMB on a specific phase of the HPV viral lifecycle, the one regarding the newly generated virions, reducing viral load and thus blocking the infection of other cervical cells.

A polyhexamethylene biguanide-assembly assisted strategy of dentin bonding greatly promotes bonding effects and caries treatment

Structural degeneration of a hybrid layer composed of a demineralized dentin matrix (DDM) and adhesive causes unsatisfactory functional outcomes in terms of bonding repair and caries treatment and is accompanied by high prevalence of secondary caries. Clinically, defects in the hybrid layer from insufficient adhesive infiltration, bacterial load from retained infected-dentin, and bacterial attack from the oral cavity are the main threats to degeneration. Currently, there is no strategy to simultaneously address adhesive penetration and bacterial infection. Herein, based on the core role of the strongly-polar hydrated DDM interface in dentin bonding, an interface-reconstructed bonding strategy assisted by electrostatic assembly of broad-spectrum germicidal polyhexamethylene biguanide (PHMB) is proposed that kills two birds with one stone. PHMB is absorbed onto the anionic 3D DDM forming a PHMB/DDM complex. The surface potential of the DDM increases by about 100 mV, the anion content decreases by 20%, and the interface water content decreases by nearly 40%. All of these changes contribute to the penetration of the adhesive, thereby improving the bonding strength and durability. After thermal cycling aging, the bonding strength of the PHMB group was 1.45-1.65 times that of the control group. In terms of antibacterial properties, PHMB treatment not only has a bacterial-killing ability due to the already formed biofilm but also significantly reduces the adhesion of bacteria, thereby delaying the occurrence of secondary caries. In summary, PHMB treatment reconstructed the DDM interface, resulting in a defect-low and inherent antibacterial hybrid layer that improves the bonding effect, treatment of caries and even prevention of secondary caries.

Comparing cytotoxicity and efficacy of miltefosine and standard antimicrobial agents against Acanthamoeba trophozoites and cyst forms: An in vitro study

Acanthamoeba keratitis (AK) is an eye disease often occurring in contact lens wearers. AK treatment is prolonged and requires multiple drugs, which can lead to adverse effects. Our study aimed to compare the in vitro activities and safety of Miltefosine with that of conventional antimicrobial agents used to treat AK. Acanthamoeba castellanii genotype T4 was obtained from a patient with keratitis and subjected to in vitro susceptibility testing with various antimicrobial agents, including Chlorhexidine (CHX), Pentamidine isethionate (PI)Polyhexamethylene biguanide (PHMB), and Miltefosine to assess their efficacy against Acanthamoeba trophozoites and cyst. The cytotoxicity of the agents was evaluated in Vero cells, and their selectivity indexes (SI) were calculated. Chlorhexidine exhibited the highest amoebicidal activity with the highest selectivity index against the trophozoite and cyst, ranging from 1.17 to 8.35. The selectivity index of PHMB is slightly comparable to Chlorhexidine, exhibiting significant anti-Acanthamoeba activity. On the other hand, Pentamidine isethionate and Miltefosine displayed low SI among the compounds. Pentamidine isethionate was effective at high concentrations, which was toxic. Miltefosine exhibited the lowest cytotoxicity; nevertheless, due to the lowest anti-Acanthamoeba activity presented a low selectivity against the parasite. Further studies on more clinical samples and prolonged incubation time should be done to investigate the effectiveness and toxicity of drugs in both in vitro and in vivo conditions.

Irrigation in Endodontics: Polyhexanide Is a Promising Antibacterial Polymer in Root Canal Treatment

Background:chronic apical periodontitis is a common pathology in dentistry, especially in endodontics. It is necessary to systematize data concerning commonly used irrigation solutions. The development of new protocols for endodontic treatment is a very promising direction. The use of a polyhexanide-based antiseptic can positively affect the results of endodontic treatment. Methods: the review was carried out involving the search for English language research and meta-analyses in the Google Scholar and PubMed databases. Results: the number of literary sources that were identified during the literature review is 180. After excluding publications that did not match the search criteria, the total number of articles included in the systematic review was determined to be 68. Conclusions: polyhexanide is a promising solution for infected root canal irrigation. The antibacterial activity of this substance is suitable for the elimination of pathogens responsible for the appearance of apical periodontitis.