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A Novel Integrated Ultrasonic Brush and Sonically Activated Lotion to Provide a Full System Approach to the Eradication of the European Head Louse Menace

Final Report Summary - CLEARBRUSH (A Novel Integrated Ultrasonic Brush and Sonically Activated Lotion to Provide a Full System Approach to the Eradication of the European Head Louse Menace)

Except for the common cold, head lice infestation is more common than all the other childhood communicable conditions combined (20 million people in the EU become infested each year with a treatment cost of approximately EUR 375 million and untold contamination problems). The current treatment, fine-tooth combing, which is unpleasant and difficult to administer, and pesticides, to which resistance is building rapidly - have failed to solve the problem. The CLEARBRUSH system is based on a full system approach to eradication of head lice.

The work carried out in the first twelve month period of the project focused on the scientific studies, development of the active lotion in aqueous base with active ingredients, development of the ultrasonic system and integration of the CLEARBRUSH components including piezoelectric actuator, brush bristles and cover. Furthermore, in vitro examinations took place, during which alternative solutions were tested for their ability to lubricate nit removal with and without ultrasound, and the first part of the clinical validation trials was also conducted on the active lotion in the aqueous base. The main design parameters of the CLEARBRUSH device and active lotion were researched; establishing layout and amplitude of the ultrasonically activated bristles, establishing the required forces at the hair surface for disrupting the egg case material with no damage to the hair shaft and scalp, and to improve human louse eradication method. Research on the physical parameters of the egg cases and egg clamp mechanism were carried out to provide input into the acoustic amplitude, the surface tension, and thixotropy / lubrication requirements of the active lotion. A validation method was developed to provide a reliable measure for verification of the activity the active lotion has against lice and their eggs. A specific in vitro testing was conducted on the active lotion and comparative products in order to evaluate lubricative and penetrative properties.

The development of the active lotion has established that certain lotions, such as aqueous emulsions, appear to have the greatest ability, especially in the presence of ultrasound, to lubricate hair and facilitate nit removal. Silicone compounds appear to be effective as well in such lubrication, however not quite as good as the aqueous solutions.

Further insight into the test results from the clinical trials shows that the effects of the silicone based formula are enhanced by ultrasound (the silicone achieves killing of head lice by coating and closing breathing openings in the head louse armour). This is in contrast to the older version of the active lotion which had lower intrinsic activity against head lice; ultrasound did not seem to increase the efficacy of this version of the active lotion. This further indicated that the neem extract which has been shown to act as an insecticide (in a number of papers) had less of a role to play in the efficacy of the CLEARBRUSH system. It was rather the coating / suffocating effect of the silicone which appears to be delivered better with the help of ultrasound and hence higher killing efficacy shown by the CLEARBRUSH system.

The research conducted also established that metals, in particular stainless steel, aluminium and titanium, had the best properties in transferring ultrasound. This discovery lead to a change in the planned work program, where the comb teeth / bristle building material, was made from stainless steel instead of the polymer material which original designs were based on. At the same time a further change, to simplify the design of the CLEABRUSH unit and making its use more reliable, was made where the plans for dispensing active lotion through the CLEARBRUSH bristles were scrapped as it was believed this would both make the production of the unit cost prohibitive and its operation unreliable due to active lotion having the potential to harden and block the dispensing mechanism. Instead the active lotion is now dispensed by hand into hair (as with other head lice treatments) and the CLEARBRUSH applied afterwards.

Work performed in the second project period focused on qualifying the design of the CLEARBRUSH unit, the making of prototype CLEARBRUSH units, further improvement of the active lotion with active ingredients, manufacture of fully functioning CLEARBRUSH prototypes as well as scale-up and manufacture of the improved active lotion, and running of full clinical validation trial involving about 140 subjects in total.

During the second project period, additional work to improve the so-called active lotion (it is necessary to coat hair with a particular type of lotion in order to allow the energy from ultrasound waves to be delivered to the site of application helping to lubricate and make combing action easier as well as functioning as a killing agent on head lice and eggs) was carried out. This resulted in a lotion with a superior efficacy in killing head lice compared with the previous version of the active lotion, although lubrication properties were not quite as good as with the previous version.

The CLEARBRUSH system has been successfully trialled in clinical validation trials on human subjects with head lice infestation, demonstrating high level of efficacy in comparison with benchmark head lice products, 82 % versus 70 % kill rate.

The partners have worked to develop robust core components which have been incorporated into the CLEARBRUSH system. The further plan is to improve on the ergonomic and aesthetic design of the CLEARBRUSH unit itself and fully establish the production process before marketing the full CLEARBRUSH system as an effective treatment for head lice infections. The plan is however to market the active lotion component as a single product first, during the course of 2008, through the distribution network established by Nelsons and Diafarm. There are further opportunities to market the treatment system for other applications such as animal healthcare and the Consortium is open to possible licensing agreements or other forms of cooperation in order to gain wide distribution of the CLEARBRUSH system, in Europe at first.