Morphine sulfate extended-release capsules for the treatment of chronic, moderate-to-severe pain

Mini-tablets as technological strategy for modified release of morphine sulfate

The aim of this study was to use intelligent formulation design for development of mini-tablets for modified release of morphine sulfate. A formulation (F1) was proposed using the Hiperstart® software. Based on the suggested formulation, two other formulations (F2 and F3) were prepared: one for modified and another for immediate drug release. The powders were characterized as bulk and tapped density, Hausner's factor and compressibility index analyzes. Mini-tablets were directly compressed and characterized as hardness, friability, size, and weight variation. The in vitro drug release profile was carried out according to the apparatus 1 of USP. Formulations showed good flow properties, and the mini-tablets displayed characteristics according to the specified. In comparison to F3 (immediate release), F1 and F2 displayed slower drug release time, showing the efficiency of the matrix formed. F3 displayed 90% of drug released up to 10 min, while F1 and F2 required 240 min. The results highlight the importance to use intelligent formulation design for the development of improved mini-tablet matrices. Formulation F1 was found to be suitable for modified morphine sulfate release. Further studies with more formulations are necessary for production of optimized mini-tablets with suitable prolonged morphine sulfate release.

PolyMorphine provides extended analgesic-like effects in mice with spared nerve injury

Morphine is a well-characterized and effective analgesic commonly used to provide pain relief to patients suffering from both acute and chronic pain conditions. Despite its widespread use and effectiveness, one of the major drawbacks of morphine is its relatively short half-life of approximately 4 h. This short half-life often necessitates multiple administrations of the drug each day, which may contribute to both dependence and tolerance to morphine. Here, we tested the analgesic properties of a new polymer form of morphine known as PolyMorphine. This polymer has monomeric units of morphine incorporated into a poly(anhydride-ester) backbone that has been shown to hydrolyze into free morphine in vitro. Using an animal model of chronic pain, the spared nerve injury surgery, we showed that PolyMorphine is able to block spared nerve injury-induced hypersensitivity in mice for up to 24-h post-administration. Free morphine was shown to only block spared nerve injury-induced hypersensitivity for up to 2-h post-injection. PolyMorphine was also shown to act through the mu opioid receptor due to the ability of naloxone (a mu opioid receptor antagonist) to block PolyMorphine-induced analgesia in spared nerve injury animals pretreated with PolyMorphine. Additionally, we observed that PolyMorphine causes similar locomotor and constipation side effects as free morphine. Finally, we investigated if PolyMorphine had any effects in a non-evoked pain assay, conditioned place preference. Pretreatment of spared nerve injury mice with PolyMorphine blocked the development of conditioned place preference for 2-methyl-6-(phenylethynyl)pyridine (MPEP), a short-lasting mGluR5 antagonist with analgesic-like properties. Free morphine does not block the development of preference for MPEP, suggesting that PolyMorphine has longer lasting analgesic effects compared to free morphine. Together, these data show that PolyMorphine has the potential to provide analgesia for significantly longer than free morphine while likely working through the same receptor.

Pain Assessment and Treatment in Children With Significant Impairment of the Central Nervous System

Pain is a frequent and significant problem for children with impairment of the central nervous system, with the highest frequency and severity occurring in children with the greatest impairment. Despite the significance of the problem, this population remains vulnerable to underrecognition and undertreatment of pain. Barriers to treatment may include uncertainty in identifying pain along with limited experience and fear with the use of medications for pain treatment. Behavioral pain-assessment tools are reviewed in this clinical report, along with other strategies for monitoring pain after an intervention. Sources of pain in this population include acute-onset pain attributable to tissue injury or inflammation resulting in nociceptive pain, with pain then expected to resolve after treatment directed at the source. Other sources can result in chronic intermittent pain that, for many, occurs on a weekly to daily basis, commonly attributed to gastroesophageal reflux, spasticity, and hip subluxation. Most challenging are pain sources attributable to the impaired central nervous system, requiring empirical medication trials directed at causes that cannot be identified by diagnostic tests, such as central neuropathic pain. Interventions reviewed include integrative therapies and medications, such as gabapentinoids, tricyclic antidepressants, α-agonists, and opioids. This clinical report aims to address, with evidence-based guidance, the inherent challenges with the goal to improve comfort throughout life in this vulnerable group of children.