Implantable and injectable drug delivery systems for pain management

Pain is a widespread global health issue, significantly affecting quality of life and contributing to disability. It is estimated that between 20% and 30% of the global population suffer from some form of non-cancer chronic pain. Around 80% of surgical patients report postoperative acute pain, with less than 50% achieving adequate pain control. Despite these statistics, the management of pain still remains a significant challenge for clinicians, with many patients experiencing poorly controlled pain or adverse effects related to analgesic medication.

This literature review outlines current pain management strategies, focusing on non-oral postoperative pain therapies, including injectable drug delivery systems (such as in situ forming implants, micro- and nano-based formulations) and implantable drug delivery systems. Emphasis is placed on solid implantable devices designed for sustained drug delivery, which can offer more efficient localized drug delivery at the pain site.

While pharmacological treatments, including oral opioids and nonsteroidal anti-inflammatory drugs, are commonly used, implantable controlled release systems are emerging as more effective alternatives. These systems provide localized pain relief with reduced systemic exposure, minimizing side effects, opioid use, and the risk of addiction, offering a promising solution for improved postoperative pain management.