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Monday, 03 March 2014 19:02

Technical Report: Spira-Wash Gel™ Wound Care Base – an Antimicrobial Evaluation

The intent of this study was to evaluate results of purposeful inoculation of the formulations with microorganisms specified in USP <51> (The United States Pharmacopeial Convention, 2013a), for nasal and inhalation use with modified Antimicrobial Effectiveness Test (AET) methodology and to quantitatively determine the in vitro effectiveness of formulations containing LoxaSperse to prevent microbial proliferation and/or kill the organisms.



Wounds are physical injuries that result from an opening or break in the skin. Wound healing starts from the moment of injury with a complex process aimed at restoring the function and integrity of damaged tissues (Rawat et al., 2012). It is categorized into three overlapping phases: inflammation (0-3 days), cellular proliferation (3-12 days) and remodeling (3-6 months) (Schmidt et al., 2009).

For centuries, plants have been used to treat several diseases worldwide. Recently there has been a dramatic increase in the usage of natural medicines in the United States. The application of plant extracts or plant-derived compounds has gained valuable momentum in the treatment and management of wounds (Suntar et al., 2012).

Many plants have been reported to have antimicrobial activity against a wide range of skin pathogens and are beneficial for wound healing. However, only a few studies have successfully incorporated natural ingredients into wound dressings, among which only a minority have led to commercially-available antimicrobial dressings, such as AmeriGel® (oak extract), MediHoneyTM, l-Mesitran® and Activon (honey) (Tan et al., 2013).

Over the last few years, there has been an increasing interest in Meadowsweet Flower Extract (Filipendula ulmaria (L.) Maxim) due to its high content of phenolic compounds, which show the potential to inhibit activity of various pathogenic microorganisms (Gniewosz et al., 2014). The phenolics together with salicylates and flavonoids also make the extract an excellent anti-inflammatory agent (Harbourne et al., 2009). It has been shown that many plants with anti-inflammatory properties most likely act through an antioxidant protection mechanism to facilitate wound healing (Suntar et al., 2012).

Spira-Wash Gel is a blend of Meadowsweet Flower Extract in a polyethylene glycol (PEG) ointment base. SpiraWash-Gel is a soft, adherent gel, which is easily water washable. It has potential use in dermatologic formulations for different applications, such as wound care, an occlusive agent, a topical humectant or infection treatment (PCCA, 2013).

The objective of this study was to examine the antimicrobial efficacy of Spira-Wash Gel, against selected bacteria and fungi through various in vitro microbiological assays. These specific pathogens were chosen due to their high incidence of occurrence in a variety of wound types.


Spira-Wash™ Gel is a water-washable wound care base containing Meadowsweet Flower Extract, which is rich in phenolic compounds, salicylates and flavonoids. They can aid in the wound healing process due to their anti-inflammatory and antimicrobial properties. This study examined the antimicrobial activity of Spira-Wash Gel by using two different in vitro antimicrobial assays: zone of inhibition (ZOI) and time-kill. Wound pathogens (C. albicans, E. coli and P.aeruginosa) and antibiotic resistant strains (MRSA and VRE) were tested. The ZOI assay indicated that Spira-Wash Gel was more effective against bacteria over fungi, with similar ZOI values for all four tested bacteria (average of 6-8 mm). It reduced the initial inoculum of E. faecium and S. aureus by 2-log10 in the first 2h of treatment, promoting death within 24h. E. coli and P. aeruginosa were completely eliminated within 1h of the time-kill assay. These results support the use of Spira-Wash Gel for wound management due to its high potential for inhibiting the growth of bacteria, with stronger action against Gram-negative bacteria.


The antibacterial activity of Spira-Wash Gel was presumably caused by high levels of phenolic acids and flavonoids in its plant extract ingredient. Moreover, Gram-negative bacteria demonstrated greater susceptibility to the base than Grampositive bacteria. Spira-Wash Gel, which is incorporated with Meadowsweet Flower Extract, is a promising anti-infective base vehicle. It exhibits positive antimicrobial properties, inhibiting the growth of bacteria to a higher degree than fungi. This study demonstrates the effectiveness of Spira-Wash Gel as an ideal vehicle, for treating a variety of bacterial wound infections.

Download the complete PDF detailing the results of this study.

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