Entrapped Painkillers within Silver

Barak Menagen, Materials, The Hebrew University, Jerousalem, Israel
David Avnir, Materials, The Hebrew University, Jerousalem, Israel

There is an ongoing interest in the development and improvement of wound dressings that will create an optimal environment for wound healing. Release of drugs from dressing to the damaged tissue is an efficient way to maximize the penetration and effectiveness of the applied drug because the release is in close proximity to the target site. In our research we entrap common analgesic drugs within silver. The purpose is to create dual-functional composite against contaminations and pain for acute and chronic wounds treatment.  We concentrated on three main groups of analgesic drugs which are used topically to reduce pain: The non-steroidal anti-inflammatory drugs (NSAID), the opioids and the local anesthetic (LA) drugs. We have successfully entrapped ibuprofen (an NSAID), tramadol (an opioid) and lidocaine (an LA) within silver, resulting in drug@Ag. The entrapment process was carried out by reducing silver nitrate in the presence of the dissolved drug with a suitable counter-ion, resulting in the incorporation of the analgesic inside the bulk aggregated silver. Upon exposure of the resulting composite to water, controlled release of the analgesic from the composite occurs while silver ions are released from the bulk and create an antiseptic activity against broad spectrum of fungi and bacteria. Full material characterization was carried out, and the release kinetics profiles were determined. The latter can be controlled and slowed down by compressing the powder.