<abstract xmlns="http://www.w3.org/1999/xhtml">Polyhexamethylene biguanide (PHMB) is an antiseptic with antiviral and antibacterial properties used in a variety of products including wound care dressings, contact lens cleaning solutions, perioperative cleansing products, and swimming pool cleaners. There are regulatory concerns with regard to its safety in humans for water treatment. We decided to assess the safety of this chemical in Sprague-Dawley rats. PHMB was administered in a single dose by gavage via a stomach tube as per the manufacturer’s instruction within a dose range of 2 mg/kg to 40 mg/kg. Subchronic toxicity studies were also conducted at doses of 2 mg/kg, 8 mg/kg and 32 mg/kg body weight and hematological, biochemical and histopathological findings of the major organs were assessed. Administration of a dose of 25.6 mg/kg, <italic>i.e.</italic> 1.6 mL of 0.4% PHMB solution (equivalent to 6.4×103 mg/L of 0.1% solution) resulted in 50% mortality. Histopathological analysis in the acute toxicity studies showed that no histopathological lesions were observed in the heart and kidney samples but 30% of the animals had mild hydropic changes in zone 1 of their liver samples, while at a dosage of 32 mg/kg in the subchronic toxicity studies, 50% of the animals showed either mild hepatocyte cytolysis with or without lymphocyte infiltration and feathery degeneration. Lymphocyte infiltration was, for the first time, observed in one heart sample, whereas one kidney sample showed mild tubular damage. The acute studies showed that the median lethal dose (LD50) is 25.6 mg/kg (LC50 of 1.6 mL of 0.4% PHMB. Subchronic toxicological studies also revealed few deleterious effects on the internal organs examined, as seen from the results of the biochemical parameters evaluated. These results have implications for the use of PHMB to make water potable.</abstract>

Polyhexamethylene biguanide (PHMB) is an antiseptic with antiviral and antibacterial properties used in a variety of products including wound care dressings, contact lens cleaning solutions, perioperative cleansing products, and swimming pool cleaners. There are regulatory concerns with regard to its safety in humans for water treatment. We decided to assess the safety of this chemical in Sprague-Dawley rats. PHMB was administered in a single dose by gavage via a stomach tube as per the manufacturer’s instruction within a dose range of 2 mg/kg to 40 mg/kg. Subchronic toxicity studies were also conducted at doses of 2 mg/kg, 8 mg/kg and 32 mg/kg body weight and hematological, biochemical and histopathological findings of the major organs were assessed. Administration of a dose of 25.6 mg/kg, i.e. 1.6 mL of 0.4% PHMB solution (equivalent to 6.4×103 mg/L of 0.1% solution) resulted in 50% mortality. Histopathological analysis in the acute toxicity studies showed that no histopathological lesions were observed in the heart and kidney samples but 30% of the animals had mild hydropic changes in zone 1 of their liver samples, while at a dosage of 32 mg/kg in the subchronic toxicity studies, 50% of the animals showed either mild hepatocyte cytolysis with or without lymphocyte infiltration and feathery degeneration. Lymphocyte infiltration was, for the first time, observed in one heart sample, whereas one kidney sample showed mild tubular damage. The acute studies showed that the median lethal dose (LD50) is 25.6 mg/kg (LC50 of 1.6 mL of 0.4% PHMB. Subchronic toxicological studies also revealed few deleterious effects on the internal organs examined, as seen from the results of the biochemical parameters evaluated. These results have implications for the use of PHMB to make water potable.

Toxicological assessment of polyhexamethylene biguanide for water treatment

Department of Pharmacology and Toxicology, University of Ghana School of Pharmacy, College of Health Sciences, Legon, Ghana

Department of Pathology, School of Biomedical and Allied Health Sciences, College of Health Sciences, Korle-Bu, Ghana

Division of Pharmacology, Faculty of Health Sciences, University of Stellenbosch, Cape Town, South Africa

Interdisciplinary Toxicology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

{"article-title":"Toxicological assessment of polyhexamethylene biguanide for water treatment"}

Polyhexamethylene biguanide (PHMB) is an antiseptic with antiviral and antibacterial properties used in a variety of products including wound care dressings,...

Toxicological assessment of polyhexamethylene biguanide for water treatment

Published Online: Mar 07, 2016

Page range: 193 - 202

Received: Jan 20, 2014

Accepted: Sep 10, 2015

DOI: https://doi.org/10.1515/intox-2015-0029

Keywords
polyhexamethylene biguanide, toxicity, biochemical hematology, histopathology, LD, therapeutic index

© 2015 Interdisciplinary Toxicology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Toxicological assessment of polyhexamethylene biguanide for water treatment

Published Online: Mar 07, 2016

Page range: 193 - 202

Received: Jan 20, 2014

Accepted: Sep 10, 2015

DOI: https://doi.org/10.1515/intox-2015-0029

Keywordspolyhexamethylene biguanide, toxicity, biochemical hematology, histopathology, LD, therapeutic index

© 2015 Interdisciplinary Toxicology

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
polyhexamethylene biguanide, toxicity, biochemical hematology, histopathology, LD, therapeutic index