Relative Abuse of Crush-Resistant Prescription Opioid Tablets via Alternative Oral Modes of Administration

Objective

Some crush-resistant tablet formulations (CRTs) reduce prescription opioid abuse by nonoral routes of administration (ROAs), especially insufflation and injection, while oral abuse increases. Oral abuse involving product manipulation vs swallowing whole for CRTs and comparators was examined.

Methods

Abuse by oral modes of administration (e.g., swallowing whole, chewing, dissolving in the mouth), was examined using the ASI-MV, a computerized, clinical interview for adults in substance abuse treatment from January 2009 to March 2015. CRTs (reformulated oxycodone extended-release [ER], reformulated oxymorphone ER, and tapentadol ER) were compared with non-CRT versions, morphine ER, and oxycodone immediate-release single entity. Analyses employed descriptive statistics and logistic regression.

Results

Among 364,329 unique assessments, 18,135 patients reported oral abuse of the CRTs and comparators examined. CRTs had a higher prevalence of oral abuse involving product manipulation than comparators (P < 0.0001) among all abusers of product. Oral abuse involving product manipulation for CRTs was greater among the subset of patients reporting oral abuse and significantly higher than comparators (P < 0.003). CRTs were significantly less likely than comparators to be swallowed whole (P < 0.0001) and significantly more likely to be chewed (P < 0.003). CRTs were more likely to be dissolved in the mouth than most comparators.

Conclusions

Results suggest the need for abuse-deterrent formulations designed to reduce abuse by oral administration with product manipulation, such as chewing. Advances in this area may reduce the overall abuse of prescription opioids and interrupt the progression from abuse by swallowing whole to oral administration involving product manipulation and other ROAs.

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.

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

Following correction should be noted.

The comparative pharmacokinetics of physical manipulation by crushing of Xtampza® ER compared with OxyContin®

AIM

To further characterize the pharmacokinetics of Xtampza^® ER.

SUBJECTS & METHODS

This was an open-label, randomized, active-controlled, five-treatment, five-period, naltrexone-blocked, cross-over study. Healthy subjects received five equivalent oxycodone doses: Xtampza ER (intact or crushed), OxyContin^® (intact or crushed) or immediate-release (IR) oxycodone (crushed). Blood samples were collected to assess oxycodone concentrations.

RESULTS

Crushed and intact Xtampza ER resulted in lower peak plasma concentrations compared with crushed oxycodone IR; crushed and intact Xtampza ER were bioequivalent. Crushed OxyContin exhibited a rapid increase in plasma oxycodone and was bioequivalent to crushed oxycodone IR.

CONCLUSION

This second pharmacokinetic study demonstrated that Xtampza ER maintains its ER properties after crushing, unlike OxyContin, which failed to retain its ER properties after crushing. ANZCTR registration number: ACTRN12614000613606.

An abuse-deterrent, microsphere-in-capsule formulation of extended-release oxycodone: alternative modes of administration to facilitate pain management in patients with dysphagia

BACKGROUND

Patients with chronic pain may experience difficulty swallowing, in part due to worsening disease, comorbid conditions, iatrogenic etiology, or age. Patients or caregivers may manipulate extended-release (ER) opioid formulations to facilitate oral dosing due to a lack of therapeutic options that allow for sprinkle or enteral feeding tube administration. If crushed or broken, current oral ER opioids can be associated with adverse sequelae, including risk of potentially fatal overdose.

OBJECTIVE

To review the safety, in vitro dissolution data, and in vivo pharmacokinetic data that support alternative modes of administration of oxycodone DETERx (Xtampza ER) via sprinkling onto soft foods for oral ingestion or via enteral feeding tubes.

METHODS

A review of oxycodone DETERx data from in vitro and in vivo studies was conducted to demonstrate support for alternative routes and modes of administration.

RESULTS

There was no difference in the dissolution profile when administered with various soft foods or when mixed with various liquid vehicles and administered via nasogastric (NG) or gastrostomy (G) tubes, based on in vitro studies. When sprinkled onto applesauce and administered orally, the microspheres were bioequivalent to the intact oxycodone capsules. When crushed or chewed, the formulation maintained its pharmacokinetic profile; no bolus dose of opioid was released. The sprinkle-dose study was limited by the single-dose study design, as well as the small sample size.

CONCLUSIONS

Oxycodone DETERx is the first ER oxycodone formulation that can be administered either intact, sprinkled onto soft foods, or via NG/G tubes, thereby providing options for treating pain in patients who have difficulty swallowing.

Oral Human Abuse Potential of Oxycodone DETERx® (Xtampza® ER)

Oxycodone DETERx^® (Collegium Pharmaceutical Inc, Canton, Massachusetts) is an extended‐release, microsphere‐in‐capsule, abuse‐deterrent formulation designed to retain its extended‐release properties after tampering (eg, chewing/crushing). This randomized, double‐blind, placebo‐controlled, triple‐dummy study evaluated the oral abuse potential of intact and chewed oxycodone DETERx capsules compared with crushed immediate‐release oxycodone. Subjects with a history of recreational opioid use who were nondependent/nontolerant to opioids were enrolled. Treatments included intact oxycodone DETERx (high‐fat, high‐calorie meal and fasted), chewed oxycodone DETERx (high‐fat, high‐calorie meal and fasted), crushed immediate‐release oxycodone (fasted), and placebo (high‐fat, high‐calorie meal). Plasma samples were collected to determine pharmacokinetic parameters. The primary endpoint was drug liking at the moment; other endpoints included drug effects questionnaire scores, Addiction Research Center Inventory/Morphine Benzedrine Group score, pupillometry measurements, and safety. Thirty‐eight subjects completed the study. Chewed and intact oxycodone DETERx were bioequivalent, unlike crushed immediate‐release oxycodone, which yielded higher peak oxycodone plasma concentrations compared with all methods of oxycodone DETERx administration. The mean maximum (peak) effect (E_max) for drug liking was significantly lower for chewed and intact oxycodone DETERx than for crushed immediate‐release oxycodone (P < .01). The time to E_max was significantly longer for chewed and intact oxycodone DETERx than for crushed immediate‐release oxycodone (P < .0001). Scores for feeling high and Addiction Research Center Inventory/Morphine Benzedrine Group scores demonstrated lower abuse potential for chewed and intact oxycodone DETERx compared with crushed immediate‐release oxycodone. Study treatments were well tolerated; no subjects experienced serious adverse events. These results demonstrate the lower oral abuse potential of chewed and intact oxycodone DETERx than crushed immediate‐release oxycodone.

A Randomized, Double-Blind, Double-Dummy Study to Evaluate the Intranasal Human Abuse Potential and Pharmacokinetics of a Novel Extended-Release Abuse-Deterrent Formulation of Oxycodone

OBJECTIVE

Evaluate the human abuse potential (HAP) of an experimental, microsphere-in-capsule formulation of extended-release oxycodone (oxycodone DETERx®) (herein "DETERx").

DESIGN

Randomized, double-blind, double-dummy, positive- and placebo-controlled, single-dose, four-phase, four-treatment, crossover study.

SETTING

Clinical research site.

SUBJECTS

There were 39 qualifying subjects (72% male, 85% white, mean age of 27 years) with 36 completing all four Double-blind Treatment Periods.

METHODS

The four phases encompassed: 1) Screening; 2) Drug Discrimination; 3) Double-blind Treatment; and 4) Follow-up. Drug Discrimination tests ensured that subjects could distinguish placebo from opioid. The four Double-blind Treatments compared DETERx-administered as either a crushed intranasal (IN) or an intact oral (PO) preparation-with immediate-release oxycodone IN (OXY-IR IN) and with an intact IN and PO placebo DETERx control.

RESULTS

For primary pharmacokinetic (PK) assessments, abuse quotient (Cmax/Tmax) was lower with DETERx IN than DETERx PO; both treatments were substantially lower than OXY-IR IN (6.24, 8.60, and 69.6 ng/mL/h, respectively). For drug liking, the primary subjective pharmacodynamic (PD) endpoint, both DETERx IN and DETERx PO produced significantly lower scores than OXY-IR IN (P ≤ 0.0001 for each); DETERx IN was less liked than DETERx PO (P ≤ 0.05), mirroring the PK relationships. Objectively assessed pupillometry corroborated the more rapid and significantly greater effect of OXY-IR IN than either DETERx IN or DETERx PO (P ≤ 0.007 for each). Overall safety profiles of DETERx and OXY-IR were comparable and both were well tolerated.

CONCLUSIONS

Pharmacokinetic and pharmacodynamic outcomes suggest that DETERx IN has relatively low HAP; continued research in larger populations is suggested.

In vitro assessment of the potential for abuse via the intravenous route of oxycodone DETERx® microspheres

OBJECTIVE

Abuse of prescription analgesics is a well-recognized problem, with nearly 2 million people aged 12 years or older initiating nonmedical use of pain relievers in 2012. The prevalence of opioid abuse via intravenous (IV) injection has led to the development of dosage forms designed to deter abuse using different inactive ingredients and formulation strategies. This study evaluated the IV abuse potential for a novel, microsphere-encapsulated abuse-deterrent formulation of oxycodone, Xtampza™ ER (referred to as "oxycodone DETERx").

METHODS

The extraction of oxycodone DETERx and two comparators, extended-release oxycodone (oxycodone ER) and immediate-release oxycodone (oxycodone IR), was evaluated in small volumes (5 and 10 mL) of water after manipulation of the dosage forms. The syringeability and injectability of these products were evaluated to determine the feasibility of using these products via IV injection.

RESULTS

The extraction of oxycodone from oxycodone DETERx was nominal, with <12 percent extracted under any test condition. Oxycodone ER and oxycodone IR had as much as 83 and 98 percent oxycodone extracted, respectively. Injectability and syringeability analyses showed that injection of oxycodone DETERx microspheres in suspension is not feasible. In contrast, oxycodone ER and oxycodone IR suspensions were more easily drawn into and expelled from a syringe. Furthermore, injection of molten oxycodone DETERx microspheres was also shown to be ineffective.

CONCLUSION

The chemical and physical properties of oxycodone DETERx provide barriers to manipulating the microspheres for the purpose of IV injection.

Comparing the Effect of Tampering on the Oral Pharmacokinetic Profiles of Two Extended-Release Oxycodone Formulations with Abuse-Deterrent Properties

OBJECTIVE

Oxycodone DETERx® is an extended-release (ER), microsphere-in-capsule abuse-deterrent-formulation designed to retain its extended-release properties following tampering or misuse (e.g., chewing, crushing). This study assessed the safety and pharmacokinetics of orally administered intact and crushed Oxycodone DETERx® capsules compared with intact and crushed reformulated OxyContin® tablets and crushed immediate-release oxycodone tablets (IR oxycodone).

METHODS

This was a randomized, open-label, active-controlled, cross-over study. Healthy subjects received five oxycodone treatments (40 mg) with a standardized high-fat, high-calorie meal: Oxycodone DETERx® (intact or crushed), OxyContin® (intact or crushed), and IR oxycodone (crushed). Blood samples were collected for assessment of oxycodone plasma concentrations.

RESULTS

Thirty-eight subjects completed the study. Both crushed and intact Oxycodone DETERx® resulted in lower peak plasma concentrations when compared with IR oxycodone. Crushed Oxycodone DETERx® was bioequivalent to intact Oxycodone DETERx® and exhibited a numerically lower Cmax . Also, median Tmax was unchanged by crushing. In contrast, mean peak plasma oxycodone concentrations for crushed OxyContin® were significantly higher compared with intact OxyContin® and were bioequivalent to IR oxycodone. Median Tmax for crushed OxyContin® was the same as IR oxycodone and 3.25 hours shorter than intact OxyContin®.

CONCLUSIONS

These data demonstrate that when crushed and taken orally, Oxycodone DETERx® maintains its EXTENDED-release profile, while crushed OxyContin® shows a pharmacokinetic profile similar to an immediate-release product. These results suggest that Oxycodone DETERx® may be less attractive to illicit drug users compared with existing abuse-deterrent-formulations, while providing a safer option for patients who may unknowingly crush their medication such as those who have difficulty swallowing.

Impact of physical manipulation on in vitro and in vivo release profiles of oxycodone DETERx®: an extended-release, abuse-deterrent formulation

OBJECTIVE

In vitro: To assess the effect of common crushing techniques on particle size reduction (PSR) and in vitro drug-release kinetics of oxycodone DETERx® (herein DETERx) and of a commercially available oxycodone extended-release (ER) tablet. In vivo: To evaluate the impact of the most effective manipulation method identified in the in vitro study and the effect of chewing on the pharmacokinetics (PK) of DETERx relative to oxycodone solution.

DESIGN

In vitro: Mechanical manipulation of dosage forms using common household utensils. In vivo: Open-label, randomized, active-controlled, crossover PK study.

SUBJECTS

In vivo: Forty-four healthy male and female volunteers.

METHODS

In vitro: DETERx capsule contents and marketed comparator tablets were subjected to manipulation (crushing) using 10 different household utensils. Particle size and dissolution analysis were conducted. In vivo: Subjects were randomly assigned to receive DETERx 40-mg capsules intact, crushed, or chewed or oxycodone solution. Serial blood samples were drawn for PK assessment.

RESULTS

In vitro: The utensils used to manipulate DETERx capsule contents were either ineffective in reducing the particle size or produced only a small change in the median particle size and dissolution rate relative to the marketed comparator. In vivo: DETERx intact capsules provided significantly lower Cmax and longer Tmax values than oxycodone solution. Manipulation of DETERx by crushing (using the most effective method established in vitro) or chewing resulted in bioequivalent plasma concentration-time profiles to the intact dosage form.

CONCLUSION

These mechanical manipulation and PK studies demonstrated that DETERx beads retained their ER properties after mechanical tampering and chewing by study subjects.

In Vitro Cytotoxicity and in Vivo Distribution after Direct Delivery of PEG−Camptothecin Conjugates to the Rat Brain

Low water solubility and rapid elimination from the brain inhibits local delivery via implants and other delivery systems of most therapeutic drugs to the brain. We have conjugated the chemotherapy drug, camptothecin (CPT), to poly(ethylene glycol) (PEG) of molecular weight 3400 using previously established protocols. These new conjugates are very water-soluble and hydrolyze at a pH-dependent rate to release the active parent drug. We have studied the uptake of these conjugates by cells in vitro and quantified their cytotoxicity toward gliosarcoma cells. These conjugates were loaded into biodegradable polymeric controlled-release implants, and their release characteristics were studied in vitro. We implanted similar polymeric disks into rat brains and used a novel sectioning scheme to determine the concentration profile of CPT in comparison to conjugated CPT in the brain after 1, 7, 14, and 28 days. We have found that PEGylation greatly increases the maximum achievable drug concentration and greatly enhances the distribution properties of CPT, compared to corelease of CPT with PEG. Although only one percent of CPT in the conjugate system was found in the hydrolyzed, active form, drug concentrations were still significantly above cytotoxic levels over a greater distance for the conjugate system. On the basis of these results, we believe that PEGylation shows great promise toward increasing drug distribution after direct, local delivery in the brain for enhanced efficacy in drug treatment.

Pharmacokinetics of the carmustine implant

Controlled release delivery of carmustine from biodegradable polymer wafers was approved as an adjunct to surgical resection in the treatment of recurrent glioblastoma multiforme after it was shown in clinical trials to be well tolerated and effective. Given the localised nature of the drug in the brain tissue, no direct pharmacokinetic measurements have been made in humans after implantation of a carmustine wafer. However, drug distribution and clearance have been extensively studied in both rodent and non-human primate brains at various times after implantation. In addition, studies to characterise the degradation of the polymer matrix, the release kinetics of carmustine and the metabolic fate of the drug and polymer degradation products have been conducted both in vitro and in vivo. GLIADEL wafers have been shown to release carmustine in vivo over a period of approximately 5 days; when in continuous contact with interstitial fluid, wafers should degrade completely over a period of 6 to 8 weeks. Metabolic elimination studies of the polymer degradation products have demonstrated that sebacic acid monomers are excreted from the body in the form of expired CO(2), whereas 1,3-bis-(p-carboxyphenoxy)propane monomers are excreted primarily through the urine. Carmustine degradation products are also excreted primarily through the urine. Pharmacokinetic studies in animals and associated modelling have demonstrated the capability of this modality to produce high dose-delivery (millimolar concentrations) within millimetres of the polymer implant, with a limited penetration distance of carmustine from the site of delivery. The limited spread of drug is presumably due to the high transcapillary permeability of this lipophilic molecule. However, the presence of significant convective flows due to postsurgical oedema may augment the diffusive transport of drug in the hours immediately after wafer implantation, leading to a larger short-term spread of drug. Additionally, in non-human primates, the presence of significant doses in more distant regions of the brain (centimetres away from the implant) has been shown to persist over the course of a week. The drug in this region was presumed to be transported from the implant site by either cerebral blood flow or cerebrospinal fluid flow, suggesting that although drug is able to penetrate the blood-brain barrier at the site of delivery, it may re-enter within the confines of the brain tissue.

Simultaneous delivery of an active protein and neutralizing antibody: creation of separated regions of biological activity

Spatial control over the biological activity of nerve growth factor (NGF) via a novel type of controlled-release device was demonstrated in an in vitro system. Two-layer polymer matrices that simultaneously released NGF and a neutralizing antibody (anti-NGF) from opposite faces were placed in PC12 cell-populated collagen gels. Biological activity in the gels was assessed over the course of 10 days by direct observation of the cells, which extend neuronal processes in the presence of NGF in a dose-dependent manner. The concentrations of both proteins in the gels were determined by ELISA as a function of distance from the polymer matrices at various time points. A boundary in biological activity was established within a few days of the initiation of the cultures; this boundary persisted and became more pronounced throughout the duration of the experiment. ELISA analysis revealed regions of high concentration of both NGF and anti-NGF on their respective sides of the polymer matrix early in the experiment. The theoretical amount of active NGF in the gel sections was calculated on the basis of these ELISA results; the concentration of active NGF in the region adjacent to the polymer correlated with the observed degree of biological response. These experiments suggest that spatial control over the biological activity of a potent agent can be obtained by an appropriately designed controlled-release device.

Extracellular enzyme synthesis in a sporulation-deficient strain of Bacillus licheniformis

A deletion of the spoIIAC gene of Bacillus licheniformis was prepared in vitro by using the splicing-by-overlap-extension technique. This gene was introduced into B. licheniformis on a temperature-sensitive plasmid, and following integration and excision from the chromosome, a precisely located deletion on the chromosomal gene was prepared. The mutated bacterium was totally asporogenous and formed abortively disporic cells characterized by asymmetric septa at the poles of the cells. Qualitative plate tests revealed that the bacterium synthesized normal levels of DNase, polygalacturonate lyase, protease, RNase, and xylanase, but the hydrolysis zones due to beta-1,3-glucanase and carboxymethyl cellulase activity were smaller in the mutant than in the parent strain. The synthesis of alkaline protease was the same in batch cultures of the mutant and the parent during prolonged incubation for 72 h, but the alpha-amylase yields were reduced by about 30% by the mutation.