Sunday, August 22, 2010

U.S. Cost Of Lost Productivity Related To Pain Is Over $100 Billion Dollars, Affects 53 Million Americans

The Board of Trustees of the University of Illinois (Chicago, IL) earned U.S. Patent 7,776,819 for a targeted drug delivery of pain and addiction therapies using opioid receptor-mediated internalization

One of the most significant health problems is the inadequate control of pain, especially chronic pain that is associated with many diseases such as cancer, back pain, arthritis, diabetic neuropathy, and other conditions. Postoperative pain affects up to 53 million patients in the United States alone. Despite most patients receiving some form of pain management, over half of these patients still experience inadequate pain relief. It is estimated that annual cost for health care and lost productivity related to pain is over $100 billion dollars in the United States. Impact of pain to society can be measured not only in economic numbers, but more importantly also by the patients' suffering.

 More than 50 million Americans live partially or totally disabled by chronic pain. There is currently no nationally accepted consensus for the treatment of chronic pain not due to cancer, yet the economic and social costs of chronic pain are substantial, with estimates ranging in the tens of billions of dollars annually. Although other areas of the world may have different protocols for pain relief, pain is a universal problem.

Morphine and other opioids have been widely used clinically for the treatment of pain. Tolerance including attenuated analgesic effect after repeated administration of opioids is well documented in clinical practice and causes inadequate treatment of pain. Pharmacological studies have established that morphine-induced analgesia, tolerance, and dependence are primarily mediated by mu opioid receptors (MOR). There have been many potential targets proposed to alleviate tolerance but many targets are intracellular. In addition, achieving cell-specific delivery presents a challenge to traditional pharmacological approach.

Opioid analgesics and traditional NSAIDs remain a mainstay of pain treatment; however, use of opioids for chronic pain leads to development of drug tolerance and drug dependence. The publications endorsed by AAPM and APS state that opioids sometimes called "narcotic analgesics," are an essential part of a pain management plan.

Impediments to the use of opioids include concerns about addiction, respiratory depression and other side effects, tolerance, diversion, and fear of regulatory action.

Inventor University of Chicago Associate Professor  of Pharmacology and Pharmaceutics
 Zaijie Jim Wang developed a novel pharmacotherapeutic approach for treatment of pain, opioid tolerance and opioid addiction prevents and/or reverses opioid tolerance and provides better pain control in a large population of patients who are being treated with opioids.

Targeted drug delivery to the intracellular component is accomplished through the combination of receptor-mediated internalization and pharmaceutical carrier systems that enhance the bioavailability of water-insoluble or non-cell permeable drugs (including peptides) by using nanoparticles such as sterically stable liposome constructs, micelles or polymer devices.

Ligand-grafted sterically stabilized liposomes (SSL) have been successfully used as an active-targeting drug delivery system that can target both cell surface and intracellular molecules in a specific cell population. Ligands can specifically bind to the corresponding receptor on the cell membrane with high affinity and selectivity. In the case of MOR, a member of G protein coupled receptors, the drug encapsulated in SSL can be delivered to the intracellular compartment via receptor-mediated endocytosis, since MOR is known to internalize with certain opioid drugs. Dermorphin (a selective MOR agonist)-grafted SSL (DPD-SSL) was actively and selectively targeted to CHO-hMOR cells showing that DPD-SSL is a drug carrier for the treatment of pain and opioid tolerance. 

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