A rapid and sensitive LC-MS/MS method for quantifying oxycodone, noroxycodone, oxymorphone and noroxymorphone in human plasma to support pharmacokinetic drug interaction studies of oxycodone.

A sensitive and reliable LC-MS/MS method was developed and validated for the quantification of oxycodone and metabolites in human plasma. The method has a runtime of 6 min and a sensitivity of 0.1 µg/L for all analytes. Sample preparation consisted of protein precipitation. Separation was performed on a Kinetix biphenyl column (2.1 × 100 mm, 1.7 µm), using ammonium formate 5 mm in 0.1% aqueous formic acid and methanol LC-MS grade 100% in gradient elution at a flow rate of 0.4 ml/min. Detection was performed in multiple reaction monitoring mode using positive electrospray ionization. The method was linear over the calibration range of 0.1-25.0 µg/L for oxycodone, noroxycodone and noroxymorphone and 0.1-5.0 µg/L for oxymorphone. The method demonstrated good performance in terms of intra- and interday accuracy (86.5-110.3%) and precision (CV 1.7-9.3%). The criteria for the matrix effect were met (CV < 15%) except for noroxymorphone, for which an additional method was applied to compensate for the matrix effect. Whole blood samples were stable for 4 h at room temperature. Plasma samples were stable for 24 h at room temperature and 3 months at -20°C. Furthermore, the method was successfully applied in a pharmacokinetic drug interaction study of oxycodone and enzalutamide in patients with prostate cancer.

Preferential Oxycodone Loss of Physically Manipulated Abuse Deterrent Oxycodone HCl Extended Release Tablets Prepared for Nasal Insufflation Studies.

A method to reproducibly mill abuse deterrent oxycodone hydrochloride (HCl) extended release (ER) tablets was developed for a nasal insufflation pharmacokinetic (PK) study. Several comminution methods were explored before determining that a conical mill resulted in controlled milling of tablets to a size range equal to or below 1000 µm. However, milling resulted in significant loss of oxycodone from abuse deterrent oxycodone HCl ER tablets compared to minimal oxycodone loss from oxycodone HCl immediate release (IR) tablets. Characterization of milled tablet powder showed that loss of oxycodone was not attributed to analytical procedures or oxycodone phase change during high intensity milling processes. The content uniformity of oxycodone in the milled tablet powder varied when ER and IR tablets were milled to a particle size distribution equal to or below 500 µm but did not vary when particles were sized above 500 µm to equal to or below 1000 µm. In addition, the initial excipient weight to drug substance weight ratio impacted the amount of oxycodone lost from the respective formulation. However, dissolution demonstrated that when oxycodone HCl ER tablets are milled, differences in excipient weight to drug substance weight ratio and particle size distribution of milled tablets did not result in significantly different release of oxycodone.

Electrochemical sensor based on glassy carbon electrode modified by polymelamine formaldehyde/graphene oxide nanocomposite for ultrasensitive detection of oxycodone.

Polymelamine formaldehyde/graphene oxide (PMF/GO) nanocomposite was used, for the first time, to study the ultrasensitive and selective electrochemical detection of oxycodone (OXC). The successful characterization of PMF/GO was verified based on scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and Raman spectroscopy. The modified GCE (PMF/GO-GCE) proved its electrocatalytic effect on OXC determination according to cyclic, linear sweep, and differential pulse voltammetry (CV, LSV, and DPV) and electrochemical impedance spectroscopy (EIS) studies. The developed sensor under optimal conditions offered a linear relationship in a limited range of  0.01 to 45 µmol L-1 with the limit of detection (LOD) of 2.0 nmol L-1. The proposed PMF/GO-GCE sensor was effectively employed for the OXC detection in human urine and serum samples. Graphical abstract.

Evaluation of Recombinant CYP3A4 Variants on the Metabolism of Oxycodone In Vitro.

Cytochrome P450 3A4 is a highly polymorphic enzyme and metabolizes approximately 40%-60% of therapeutic drugs. Its genetic polymorphism may significantly affect the expression and function of CYP3A4 resulting in alterations of the pharmacokinetics and pharmacodynamics of the CYP3A4-mediated drugs. The purpose of this study was to evaluate the catalytic activities of 30 CYP3A4 nonsynonymous variants and wild type toward oxycodone in vitro. CYP3A4 proteins were incubated with oxycodone for 30 min at 37 °C and the reaction was terminated by cooling to -80 °C immediately. Ultraperformance liquid chromatography tandem mass-spectrometry was used to analyze noroxycodone, and kinetic parameters Km, Vmax, and intrinsic clearance (Vmax/Km) of noroxycodone were also determined. Compared with CYP3A4.1, 24 CYP3A4 variants (CYP3A4.2-.5, -.7-.16, -.18 and -.19, -.23 and -.24, -.28 and -.29, and -.31-.34) exhibited significantly decreased relative clearance values (from 4.82% ± 0.31% to 80.98% ± 5.08%), whereas CYP3A4.6, -.17, -.20, -.21, -.26, and -.30 displayed no detectable enzyme activity. As the first study of these alleles for oxycodone metabolism in vitro, results of this study may provide insight into establishing the genotype-phenotype relationship for oxycodone and serve as a reference for clinical administrators and advance the provision of personalized precision medicine.

Effect of physical manipulation on the oral pharmacokinetic profile of Xtampza® ER (oxycodone DETERx® formulation): A review of published studies.

Opioids can be an effective treatment option for appropriate patients with chronic pain for whom nonpharmacological or nonopioid treatment does not provide adequate pain relief. However, extended-release (ER) opioid formulations, because of their high drug content, are attractive options for nonmedical use and abuse. Xtampza® ER (oxycodone DETERx®) capsules, an ER abuse-deterrent formulation (ADF), contain microspheres that combine oxycodone with inactive ingredients to increase the difficulty of tampering with the ER mechanism. The aim of this article is to review five previously published studies highlighting the impact of physical manipula-tion (ie, crushing and chewing) on the pharmacokinetic (PK) properties of orally administered Xtampza ER compared with immedi-ate-release (IR) oxycodone and/or reformulated OxyContin® (the first approved oxycodone ER ADF). Across five studies, manipulated (crushed or chewed) Xtampza ER retained an ER PK profile similar to that of intact Xtampza ER, with respect to maximum plasma con-centration (Cmax) and time to Cmax. Additionally, bioequivalence was established between manipulated and intact Xtampza ER, based on Cmax and area under the concentration-time curve values in healthy volunteers and nondependent recreational opioid users. In contrast, crushed OxyContin failed to retain the ER PK profile of intact OxyContin and was bioequivalent to IR oxycodone, based on Cmax in healthy volunteers. The retention of ER PK properties when capsule contents are physically manipulated before oral administra-tion suggests Xtampza ER has lower potential to be manipulated for oral abuse when compared with IR oxycodone or OxyContin.

Organophotocatalytic N-Demethylation of Oxycodone Using Molecular Oxygen.

N-Demethylation of oxycodone is one of the key steps in the synthesis of important opioid antagonists like naloxone or analgesics like nalbuphine. The reaction is typically carried out using stoichiometric amounts of toxic and corrosive reagents. Herein, we present a green and scalable organophotocatalytic procedure that accomplishes the N-demethylation step using molecular oxygen as the terminal oxidant and an organic dye (rose bengal) as an effective photocatalyst. Optimization of the reaction conditions under continuous flow conditions using visible-light irradiation led to an efficient, reliable, and scalable process, producing noroxycodone hydrochloride in high isolated yield and purity after a simple workup.

Chemoenzymatic Total Synthesis of (+)-10-Keto-Oxycodone from Phenethyl Acetate.

The total synthesis of (+)-10-keto-oxycodone was attained from phenethyl acetate in a stereoselective manner. Absolute stereochemistry was established via enzymatic dihydroxylation of phenethyl acetate with the recombinant strain JM109 (pDTG601A) that furnished the corresponding cis-cyclohexadienediol whose configuration corresponds to the absolute stereochemistry of the ring C of (+)-10-keto-oxycodone. Intramolecular Heck reaction was utilized to establish the quaternary carbon at C-13, along with the dibenzodihydrofuran functionality. The C-14 hydroxyl and C-10 ketone were installed via SmI2-mediated radical cyclization, and oxidation of a benzylic alcohol (obtained from an intermediate nitrate azide), respectively. The synthesis of (+)-10-keto-oxycodone was completed in a total of 14 operations (21 steps) and an overall yield of ~2%. Experimental and spectral data are provided for key intermediates and new compounds.

Preparation of bivalent agonists for targeting the mu opioid and cannabinoid receptors.

In order to obtain novel pharmacological tools and to investigate a multitargeting analgesic strategy, the CB1 and CB2 cannabinoid receptor agonist JWH-018 was conjugated with the opiate analgesic oxycodone or with an enkephalin related tetrapeptide. The opioid and cannabinoid pharmacophores were coupled via spacers of different length and chemical structure. In vitro radioligand binding experiments confirmed that the resulting bivalent compounds bound both to the opioid and to the cannabinoid receptors with moderate to high affinity. The highest affinity bivalent derivatives 11 and 19 exhibited agonist properties in [35S]GTPγS binding assays. These compounds activated MOR and CB (11 mainly CB2, whereas 19 mainly CB1) receptor-mediated signaling, as it was revealed by experiments using receptor specific antagonists. In rats both 11 and 19 exhibited antiallodynic effect similar to the parent drugs in 20 µg dose at spinal level. These results support the strategy of multitargeting G-protein coupled receptors to develop lead compounds with antinociceptive properties.

Chemoenzymatic Total Synthesis of ent-Oxycodone: Second-, Third-, and Fourth-Generation Strategies.

Four distinct approaches to ent-oxycodone were designed and accomplished. All rely on the same starting material, the diene diol derived from phenethyl acetate by the whole-cell fermentation with E. coli JM109 (pDTG601A), a strain that overexpresses toluene dioxygenase. The key step in the first-generation approach involves the construction of the C-9/C-14 bond by a SmI2-mediated cyclization of a keto aldehyde. The second-generation design relies on the use of the Henry reaction to accomplish this task. In both of these syntheses, Parker's cyclization was employed to construct the D-ring. The third-generation synthesis provides an improvement over the second in that the nitrogen atom at C-9 is introduced by azidation of the C-9/C-10 olefin, followed by reduction and lactam formation between the C-9 amine and the Fukuyama-type lactone. Finally, the fourth generation takes advantage of the keto-nitrone reductive coupling to generate the C-9/C-14 linkage. The four generations of the total syntheses of ent-oxycodone were accomplished in 13, 18, 16, and 11 operations (19, 23, 24, and 18 steps), respectively. Experimental and spectral data are provided for all new compounds.

An alternating polarity switching assay for quantification of oxycodone and topiramate: An application of LC-MS/MS method in support to PK/PD study in rodents.

In mass spectrometry, compounds that have different ionization properties experience challenges in simultaneous analysis. In the present paper, the authors proposed a polarity switching (+ve and -ve) LC-MS/MS method to analyze oxycodone and topiramate in a single run. The developed method was validated in the range of 5-1000 ng/mL for oxycodone and 20-5000 ng/mL for topiramate as per the US FDA guidelines. The mass spectrometer was operated in multiple reaction monitoring (MRM) mode to analyze oxycodone and topiramate simultaneously using oxycodone-d6 and topiramate-d12 as internal standards, respectively. Sample preparation was performed in 96-well protein precipitation plates using acetonitrile. Processed samples were analyzed using a C18 column with a gradient mobile phase composed of 10 mm ammonium formate with 0.1% formic acid and acetonitrile. The method was validated for selectivity, specificity, linearity, precision and accuracy, dilution integrity and stability. After validation, this method was successfully applied to quantify oxycodone and topiramate in plasma of concomitantly treated Sprague Dawley (SD) rats.

Alum adjuvant is more effective than MF59 at prompting early germinal center formation in response to peptide-protein conjugates and enhancing efficacy of a vaccine against opioid use disorders.

Opioid use disorders (OUD) and fatal overdoses are a national emergency in the United States. Therapeutic vaccines offer a promising strategy to treat OUD and reduce the incidence of overdose. Immunization with opioid-based haptens conjugated to immunogenic carriers elicits opioid-specific antibodies that block opioid distribution to the brain and reduce opioid-induced behavior and toxicity in pre-clinical models. This study tested whether the efficacy of a lead oxycodone conjugate vaccine was improved by formulation in either aluminum hydroxide or the squalene-based oil-in-water emulsion MF59 adjuvant, which was recently FDA-approved for influenza vaccines in subjects 65+ years old. In adult BALB/c mice, alum formulation was more effective than MF59 at promoting the early expansion of hapten-specific B cells and the production of oxycodone-specific serum IgG antibodies, as well as blocking oxycodone distribution to the brain and oxycodone-induced motor activity. Alum was also more effective than MF59 at promoting early differentiation of peptide-specific MHCII-restricted CD4+ Tfh and GC-Tfh cells in adult C57Bl/6 mice immunized with a model peptide-protein conjugate. In contrast, alum and MF59 were equally effective in promoting hapten-specific B cells and peptide-specific MHCII-restricted CD4+ T cell differentiation in older C57Bl/6 mice. These data suggest that alum is a more effective adjuvant than MF59 for conjugate vaccines targeting synthetic small molecule haptens or peptide antigens in adult, but not aged, mice.

Evaluation of the oral human abuse potential of Oxycodone DETERx® formulation (Xtampza® ER).

OBJECTIVE: To further characterize the human abuse potential and pharmacokinetics (PK) of Oxycodone DETERx (Xtampza® ER) after intact and chewed oral administration. DESIGN: Randomized, double-blind, triple-dummy, active- and placebo-controlled, single-dose, six-period, crossover comparison study. SETTING: Clinical research unit. SUBJECTS: Adult, nondependent recreational opioid users who liked the effects of crushed immediate-release (IR) oxycodone in solution and were able to differentiate the effects from placebo solution. INTERVENTIONS: Oral administration of intact Oxycodone DETERx (fasted and fed), chewed Oxycodone DETERx (fasted and fed), crushed IR oxycodone (fasted), and placebo (fed). MAIN OUTCOME MEASURES: Subject ratings (100-point visual analog scales) of Drug Liking (primary measure) and Take Drug Again (key secondary measure). RESULTS: The pharmacodynamic (PD) analysis included 52 subjects who completed the study; the PK analysis included 71 subjects. Compared with crushed IR oxycodone fasted, the least-squares mean maximum effect (Emax) was statistically significant (p < 0.01) for Drug Liking and Take Drug Again, respectively, for chewed Oxycodone DETERx fasted (LS mean difference ± standard error of the mean: 13.1 ± 2.2 and 10.0 ± 3.2 points) and fed (10.9 ± 2.2 and 9.7 ± 3.3 points) and intact Oxycodone DETERx fasted (12.2 ± 2.2 and 9.3 ± 3.3 points) and fed (10.3 ± 2.2 and 9.2 ± 3.3 points). Results were consistent for other PD measures (Good Effects, Feeling High). Chewed Oxycodone DETERx fasted and fed treatments were bioequivalent to the respective intact treatments based on PK parameters. CONCLUSIONS: This study showed that when chewed or swallowed intact, under fasted or fed conditions, Oxycodone DETERx had statistically significantly lower abuse potential via the oral route compared with IR oxycodone.

Preclinical Efficacy and Characterization of Candidate Vaccines for Treatment of Opioid Use Disorders Using Clinically Viable Carrier Proteins.

Vaccines may offer a new treatment strategy for opioid use disorders and opioid-related overdoses. To speed translation, this study evaluates opioid conjugate vaccines containing components suitable for pharmaceutical manufacturing and compares analytical assays for conjugate characterization. Three oxycodone-based haptens (OXY) containing either PEGylated or tetraglycine [(Gly)4] linkers were conjugated to a keyhole limpet hemocyanin (KLH) carrier protein via carbodiimide (EDAC) or maleimide chemistry. The EDAC-conjugated OXY(Gly)4-KLH was most effective in reducing oxycodone distribution to the brain in mice. Vaccine efficacy was T cell-dependent. The lead OXY hapten was conjugated to the KLH, tetanus toxoid, diphtheria cross-reactive material (CRM), as well as the E. coli-expressed CRM (EcoCRM) and nontoxic tetanus toxin heavy chain fragment C (rTTHc) carrier proteins. All vaccines induced early hapten-specific B cell expansion and showed equivalent efficacy against oxycodone in mice. However, some hapten-protein conjugates were easier to characterize for molecular weight and size. Finally, heroin vaccines formulated with either EcoCRM or KLH were equally effective in reducing heroin-induced antinociception and distribution to the brain of heroin and its metabolites in mice. This study identifies vaccine candidates and vaccine components for further development.

Conditional power for assessing population interventions.

AIM: To calculate conditional power in comparative two-period studies with previously observed baseline data. METHOD: Isolate the variability attributable to the yet-to-observed data and modify the standard power formulae. RESULTS: For illustration, we examine rates of opioid overdose before and after a reformulation of one opioid product. The null hypothesis posited no impact of the reformulation, alternative hypotheses posited possible impacts, and ancillary hypotheses posited different secular pre-post changes directly observable in comparators. Conditional power varied with the size of the comparator population and with the assumed pre-post change for the comparator. CONCLUSION: Pre-post designs can be initiated after the baseline period is over. Power calculations that are conditioned on observed baseline data account differently for variability in the baseline and follow-up periods.

The DARK Side of Total Synthesis: Strategies and Tactics in Psychoactive Drug Production.

Humankind has used and abused psychoactive drugs for millennia. Formally, a psychoactive drug is any agent that alters cognition and mood. The term "psychotropic drug" is neutral and describes the entire class of substrates, licit and illicit, of interest to governmental drug policy. While these drugs are prescribed for issues ranging from pain management to anxiety, they are also used recreationally. In fact, the current opioid epidemic is the deadliest drug crisis in American history. While the topic is highly politicized with racial, gender, and socioeconomic elements, there is no denying the toll drug mis- and overuse is taking on this country. Overdose, fueled by opioids, is the leading cause of death for Americans under 50 years of age, killing ca. 64,000 people in 2016. From a chemistry standpoint, the question is in what ways, if any, did organic chemists contribute to this problem? In this targeted review, we provide brief historical accounts of the main classes of psychoactive drugs and discuss several foundational total syntheses that ultimately provide the groundwork for producing these molecules in academic, industrial, and clandestine settings.

The effect of a potentially tamper-resistant oxycodone formulation on opioid use and harm: main findings of the National Opioid Medications Abuse Deterrence (NOMAD) study.

BACKGROUND: Escalation of pharmaceutical opioid use and harm in North America is well-documented, with similar issues emerging in Australia. One response is the development of tamper-resistant formulations of opioids. A potentially tamper-resistant formulation of controlled-release oxycodone was introduced in Australia in April, 2014, rapidly replacing the non-tamper-resistant formulation. Our study is the most systematic and comprehensive examination of the impact of a new opioid formulation to date, assessing the effect of tamper-resistant formulation of controlled-release oxycodone on population-level opioid use and opioid-related harm (ie, overdose, help-seeking, and treatment-seeking); and opioid use, tampering, and preference for the tamper-resistant formulation of controlled-release oxycodone compared with other drugs or formulations among sentinel populations likely to tamper with pharmaceutical opioids. METHODS: We conducted interrupted time-series analyses of opioid sales data and multiple routinely collected health datasets, followed up a cohort of people who tamper with pharmaceutical opioids before and after the introduction of the tamper-resistant formulation of controlled-release oxycodone, and analysed annual surveys of people who inject drugs. Data were collected from several Australian states: New South Wales, South Australia, and Tasmania. Meta-analyses (weighted Z tests) were conducted to synthesise across data sources providing evidence for a given indicator. FINDINGS: At the population level, we found reduced sales of higher strengths of controlled-release oxycodone and increased sales of other oxycodone formulations. No significant effect was observed among population-level indicators of opioid overdose, or help or treatment-seeking. Mortality data were not available for inclusion at the time of our study. Meta-analyses across sentinel populations (ie, prospective cohort, surveys of people who inject drugs, and clients of supervised injecting facilities or needle and syringe programmes) indicated reduced controlled-release oxycodone use via tampering (mainly injection), with no evidence of switching to heroin or other drug use. INTERPRETATION: This formulation of controlled-release oxycodone reduced tampering with pharmaceutical opioids among people who inject drugs, but did not affect population-level opioid use or harm. FUNDING: Mundipharma Australia, the Australian Government, and the National Health and Medical Research Council.

Abuse-deterrent properties of REMOXY® ER, a high-viscosity extended-release oxycodone formulation.

OBJECTIVE: These in vitro studies compared abuse-deterrent properties of REMOXY ER (extended-release oxycodone), a novel, high-viscosity gel formulation, versus the two currently marketed ER oxycodone formulations. METHODS: Tampering methods were tailored to each product to maximize oxycodone release with the least complexity, time, and effort, based on the physical/chemical properties of each formulation. Oral abuse was simulated by extracting oxycodone from each manipulated formulation in Common Ingestible Liquids and in Advanced Solvents (not ingestible and requiring additional separation). To simulate injection abuse, oxycodone was extracted from each manipulated formulation in low volumes of injection vehicles, heated or unheated. Inhalation abuse potential was assessed by volatilization. RESULTS: In oral abuse simulations, manipulated REMOXY ER released 2-22 percent of its oxycodone in 20 minutes in five Common Ingestible Liquids, versus 77-85 percent oxycodone released from OxyContin® ER in 5 minutes in four of the five. In six Advanced Solvents, REMOXY ER released 3-37 percent at 20 minutes, versus 55-89 percent released from OxyContin ER at 5 minutes. Minimal oxycodone was extracted from REMOXY ER in five injection vehicles, heated or unheated. In contrast, OxyContin ER released 65-87 percent of its oxycodone within 10 minutes in all vehicles, regardless of heating. Xtampza® ER released 96 percent of its oxycodone in a heated injection vehicle and released 50-60 percent in two unheated injection vehicles. Showing minimal inhalation abuse potential, 9 percent of oxycodone was vaporized from manipulated REMOXY ER at 20 minutes compared to 8.8 percent at 5 minutes for OxyContin ER. CONCLUSIONS: In these studies, REMOXY ER demonstrated robust and meaningful abuse-deterrence relative to OxyContin ER and Xtampza ER. PERSPECTIVE: Abuse-deterrent drugs were intended to help fight opioid abuse. Yet, the persistence of the opioid epidemic indicates that vast improvements in abuse-deterrent technology are sorely needed. A new, high-viscosity, ER oxycodone formulation showed much improved abuse-deterrent properties in simulations of oral, injection, and inhalation abuse, compared to earlier, first-generation formulations.

In Vitro Drug Release After Crushing: Evaluation of Xtampza® ER and Other ER Opioid Formulations.

BACKGROUND AND OBJECTIVE: Extended-release (ER) opioids are associated with high rates of abuse. Recreational opioid users often manipulate ER formulations to achieve a high plasma concentration in a short amount of time, resulting in a more rapid and intense high. Patients may also manipulate ER tablets to facilitate swallowing, without recognizing that manipulation could increase release rate. The goal of this study was to assess the ability of oxycodone DETERx (Xtampza® ER, Collegium Pharmaceutical, Inc., Canton, MA, USA) and other commercially available ER opioid formulations with and without physicochemical abuse-deterrent characteristics to be manipulated by crushing in an in vitro setting. METHODS: In vitro dissolution techniques were used to compare the opioid release from a variety of ER opioid formulations. Dissolution was assessed for intact and crushed dosage forms. Opioid release was quantified using high-performance liquid chromatography. RESULTS: Intact formulations exhibited drug release rates characteristic of 12- or 24-h dosage forms. After crushing using commonly available household tools, only Xtampza ER maintained ER of opioid. CONCLUSIONS: Xtampza ER maintained its ER characteristics after crushing, unlike many other commercially available opioid formulations, including some formulated with abuse-deterrent properties. As such, Xtampza ER may be less appealing to abusers and offer a margin of safety for patients who manipulate dosage forms to facilitate swallowing.