Adamis Pharmaceuticals (United States)

Abstract Background: Previously, we reported on an opioid receptor quantitative systems pharmacology (QSP) model to evaluate naloxone dosing. Methods: In this study we extended our model to include higher systemic levels of fentanyl (up to 100 ng/ml) and the newly approved 8mg IN naloxone dose (equivalent to 4 mg)Results : As expected, at the lower peak fentanyl concentrations (25 ng/ml and 50 ng/ml), the simulations predicted that 2 mg, 4 mg, 5 mg, and 10 mg IM doses of naloxone displaced fentanyl and reached below the 50% receptor occupancy within 10 minutes. However, at the concentration of 75 ng/ml, the simulation predicted that the 2 mg dose of naloxone failed to reach below the 50% occupancy within 10 minutes. Interestingly, at the highest peak concentration of fentanyl studied (100 ng/ml), the model predicted that the 4 mg of naloxone IM (equivalent to 8 mg IN) failed to reach below the threshold of 50 % occupancy within 10 minutes or even within 15 minutes (Data not shown). In contrast, the model predicted successful reversals when 5 and 10 mg IM doses were utilized. Conclusion:These results support the notion that acutely administered higher doses of naloxone are needed for rapid and adequate clinical reversal, particularly when higher systemic exposure of the potent synthetic opioids occur.

There has been a dramatic increase of deaths due to illicit fentanyl. We examined the pharmacology of fentanyl and reviewed data on the number of repeat doses of naloxone used to treat fentanyl overdoses. Multiple sequential doses of naloxone have been required in a certain percentage of opioid overdoses due to fentanyl. In addition, fentanyl appears to differ from other opioids as having a very rapid onset with high systemic levels found in overdose victims. A rapid competition is required by naloxone to out-compete large numbers of opioid receptors occupied by fentanyl in the CNS. Taken together, we propose that higher doses of naloxone are needed to combat the new era of overdoses due to the more potent synthetic opioids such as fentanyl.

A phase 1/2a dose escalation study of APC-100 (2,2,5,7,8-Pentamethyl-6-chromanol) was conducted to determine maximum tolerated dose (MTD), recommended phase 2 dose, toxicities and efficacy in men with castrate-resistant prostate cancer (CRPC). This open label phase 1/2a study utilizes a time-to-event reassessment method (TITE-CRM) design. Patients in cohorts of 3 were treated with escalating doses of APC-100 (900 mg-2400 mg) orally once daily continuously. Cycles were 28 days. Twenty patients with CRPC were enrolled in the dose escalation cohort. One possible DLT (elevated ALT) was seen at dose level 1. No other DLTs were seen and no dose reductions were required. Most frequent AEs included nausea (grade 1 in 6 patients) and elevated transaminases (grade 1-3 in 5 patients). After enrolment of 20 patients the MTD was not reached, however the maximal feasible dose was exceeded due to the number of capsules ingested. Five of the 20 patients had stable disease as their best response. The median progression free survival (PFS) for the cohort was 2.8 months (range 1-8). APC-100 is a novel agent with dual mechanism of action functioning both as potent antioxidant as well as antiandrogen. No detectable APC-100 was found in the plasma at dose level 5 (2100 mg) and it was felt that maximal feasibility was nearly reached. APC-100 is being reformulated as a tablet to allow further dose escalation. Once a recommended phase 2 dose is established, future studies in prostate cancer chemoprevention should be conducted.

Abstract Electron Monte Carlo calculations using CYLTRAN and a new PHSECE (photon produced secondary electrons) technique were carried out to estimate electron fluences and energy deposition profiles near LiF/Al and LiF/Pb material interfaces undergoing 60Co irradiation. Several interesting and new features emerge: (i) Although the build-up of the secondary electron fluences at the interfaces of the irradiated media is approximately exponential, the value of the electron mass fluence build-up coefficient, ?, is not equal to the electron mass fluence attenuation coefficient, ß. (ii) The ß value of the attenuation of the gamma generated electron fluences at the cavity-medium interfaces is strongly dependent on the Z of the adjacent material. (iii) For LiF/Pb there is a significant 'intrusion' energy deposition mode arising from 'side-scattering' in the wall (Pb) material. These new features of interface dosimetry (at least (i) and (ii)) are incorporated into photon general cavity theory and compared with experimental data.