Development and Preliminary Experience with an Ease of Extractability Rating System for Prescription Opioids

Physical Barrier Type Abuse-Deterrent Formulations: Mechanistic Understanding of Sintering-Induced Microstructural Changes in Polyethylene Oxide Placebo Tablets

The main goal of the presented work was to understand changes in the microstructure of tablets, as well as the properties of its main component viz. polyethylene oxide (PEO) as a function of sintering. Key polymer variables and sintering conditions were investigated, and sintering-induced increase in tablet tensile strength was evaluated. For the current study, binary-component placebo tablets comprised of varying ratios of PEO and anhydrous dibasic calcium phosphate (DCP) were prepared at two levels of tablet solid fraction. The prepared tablets were sintered in an oven at 80°C at different time points ranging from 10 to 900 min and were evaluated for pore size, tablet expansion (%), and PEO crystallinity. The results showed that for efficient sintering and a significant increase in the tablet tensile strength, a minimum of 50% w/w PEO was required. Moreover, all microstructural changes in tablets were found to occur within 60 min of sintering, with no significant changes occurring thereafter. Sintering also resulted in a decrease in PEO crystallinity, causing changes in polymer ductility. These changes in PEO ductility resulted in tablets with higher tensile strength. Formulation variables such as PEO level and PEO particle size distribution were found to be important influencers of the sintering process. Additionally, tablets with high initial solid fraction and sintering duration of 60 min were found to be optimal conditions for efficient sintering of PEO-based compacts. Finally, prolonged sintering times were not found to provide any additional benefits in terms of abuse-deterrent properties.

In Vitro Assessment of Nasal Insufflation of Comminuted Drug Products Designed as Abuse Deterrent Using the Vertical Diffusion Cell

In vitro evaluation of abuse deterrent formulations (ADFs) is a challenge since real abuse situations are variable and ADF technology is evolving. Specifically, an assessment of an ADF to deter nasal insufflation would be valuable. In this study, a vertical diffusion cell (VDC) was used to evaluate polyethylene oxide (PEO)-based tablets manipulated by three different forces. The commercially available products Oxycontin®, an ADF, Opana®, and metoprolol tartrate tablet formulations made in our laboratory were studied. Particle size distribution and percent recovery of manipulated tablets were measured. Grinding produced the lowest recovery and the smallest particle size distribution. Drug release was examined using a VDC by placing the dry comminuted particles on an enclosed wetted cellulose membrane. Dispensing dry particles on a VDC is atypical but includes some key features associated with an abuse situation where once the particles are snorted, the moisture in the nasal mucosa activates hydration and swelling of the polymers in the formulation, retarding drug release. Drug release from OxyContin®, Opana®, and metoprolol tablets were analyzed for the cutting, grinding, and milling modes of abuse. The analysis showed that in most cases, the mode of abuse produced different particle sizes with different release rates. Statistically different release rates were observed for metoprolol tablets made with different molecular weight PEO and with different porosities. These results indicate that within detection limits, the VDC can be used to quantitate release differences due to various modes of abuse used in this study.

Risk based in vitro performance assessment of extended release abuse deterrent formulations

High strength extended release opioid products, which are indispensable tools in the management of pain, are associated with serious risks of unintentional and potentially fatal overdose, as well as of misuse and abuse that might lead to addiction. The issue of drug abuse becomes increasingly prominent when the dosage forms can be readily manipulated to release a high amount of opioid or to extract the drug in certain products or solvents. One approach to deter opioid drug abuse is by providing novel abuse deterrent formulations (ADF), with properties that may be viewed as barriers to abuse of the product. However, unlike regular extended release formulations, assessment of ADF technologies are challenging, in part due to the great variety of formulation designs available to achieve deterrence of abuse by oral, parenteral, nasal and respiratory routes. With limited prior history or literature information, and lack of compendial standards, evaluation and regulatory approval of these novel drug products become increasingly difficult. The present article describes a risk-based standardized in-vitro approach that can be utilized in general evaluation of abuse deterrent features for all ADF products.

A comparison among tapentadol tamper-resistant formulations (TRF) and OxyContin® (non-TRF) in prescription opioid abusers

AIMS

To examine whether tamper-resistant formulations (TRFs) of tapentadol hydrochloride extended-release (ER) 50 mg (TAP50) and tapentadol hydrochloride 250 mg (TAP250) could be converted into forms amenable to intranasal (study 1) or intravenous abuse (study 2).

DESIGN

Randomized, repeated-measures study designs were employed. A non-TRF of OxyContin® 40 mg (OXY40) served as a positive control. No drug was taken in either study.

SETTING

The studies took place in an out-patient setting in New York, NY.

PARTICIPANTS

Twenty-five experienced, healthy ER oxycodone abusers participated in each study.

MEASUREMENTS

The primary outcome for study 1 was the percentage of participants who indicated that they would snort the tampered tablets, while the primary outcome for study 2 was the percentage yield of active drug in solution. Other descriptive variables, such as time spent manipulating the tablets, were also examined to characterize tampering behaviors more clearly.

FINDINGS

Tampered TRF tablets were less desirable than the tampered OXY40 tablets. Few individuals were willing to snort the TRF particles (TAP50: 24%, TAP250: 16%; OXY40: 100% P < 0.001). There was less drug extracted from the TAP50 tablet than from the OXY40 tablet (3.52 versus 37.02%, P = 0.008), and no samples from the TAP250 tablets contained analyzable solutions of the drug. It took participants longer to tamper with the TAPs (study 1: TAP50 versus OXY40, P < 0.01; TAP250 versus OXY40, P < 0.01; study 2: TAP250 versus OXY40, P < 0.05).

CONCLUSIONS

Tamper-resistant formulations of taptentadol (pain relief) tablets do not appear to be well-liked by individuals who tamper regularly with extended-release oxycodone tablets. Employing tamper-resistant technology may be a promising approach towards reducing the abuse potential of tapentadol extended-release.

Oxycodone combined with opioid receptor antagonists: efficacy and safety

INTRODUCTION

A mu receptor antagonist combined with oxycodone (OXY) may improve pain control, reduce physical tolerance and withdrawal, minimizing opioid-related bowel dysfunction and act as an abuse deterrent.

AREAS COVERED

The authors cover the use of OXY plus ultra-low-dose naltrexone for analgesia and the use of sustained-release OXY plus sustained-release naloxone to reduce the opioid bowel syndrome. The authors briefly describe the use of sustained-release OXY and naltrexone pellets as a drug abuse deterrent formulation. Combinations of ultra-low-dose naltrexone plus OXY have been in separate trials involved in patients with chronic pain from osteoarthritis and idiopathic low back pain. High attrition and marginal differences between ultra-low-dose naltrexone plus OXY and OXY led to discontinuation of development. Prolonged-release (PR) naloxone combined with PR OXY demonstrates a consistent reduction in opioid-related bowel dysfunction in multiple randomized controlled trials. However, gastrointestinal side effects, including diarrhea, were increased in several trials with the combination compared with PR OXY alone. Analgesia appeared to be maintained although non-inferiority to PR OXY is not formally established. There were flaws to trial design and safety monitoring. Naltrexone has been combined with OXY in individual pellets encased in a capsule. This combination has been reported in a Phase II trial and is presently undergoing Phase III studies.

EXPERT OPINION

Due to the lack of efficacy the combination of altered low-dose naltrexone with oxycodone should cease in development. The combination of sustained release oxycodone plus naloxone reduces constipation with a consistent benefit. Safety has been suboptimally evaluated which is a concern. Although the drug is commercially available in several countries, ongoing safety monitoring particularly high doses would be important.

Assessment of a formulation designed to be crush-resistant in prescription opioid abusers

BACKGROUND

The extent of prescription opioid abuse has led to the development of formulations that are difficult to crush. The purpose of the present studies was to examine whether experienced prescription opioid abusers (individuals using prescription opioids for non-medical purposes regardless of how they were obtained) were able to prepare a formulation of oxymorphone hydrochloride ER 40 mg designed to be crush-resistant (DCR) for intranasal (study 1) or intravenous abuse (study 2), utilizing a non-crush-resistant formulation of oxymorphone (40 mg; OXM) as a positive control.

METHODS

No drug was administered in these studies. Participants were provided with DCR and OXM tablets in random order and asked to prepare them for abuse with tools/solutions that they had previously requested. The primary outcome for study 1 was particle size distribution, and the primary outcome for study 2 was percent yield of active drug in the extracts. Other descriptive variables were examined to better understand potential responses to these formulations.

RESULTS

Fewer DCR than OXM particles were smaller than 1.705 mm (9.8% vs. 97.7%), and thus appropriate for analyses. Percent yield of active drug in extract was low and did not differ between the two formulations (DCR: 1.95%; OXM: 1.29%). Most participants were not willing to snort (92%) or inject (84%) the tampered products. Participants indicated that they found less relative value in the DCR than the OXM formulation across both studies.

CONCLUSIONS

These data suggest that the oxymorphone DCR formulations may be a promising technology for reducing opioid abuse.

Research design considerations for clinical studies of abuse-deterrent opioid analgesics: IMMPACT recommendations

Opioids are essential to the management of pain in many patients, but they also are associated with potential risks for abuse, overdose, and diversion. A number of efforts have been devoted to the development of abuse-deterrent formulations of opioids to reduce these risks. This article summarizes a consensus meeting that was organized to propose recommendations for the types of clinical studies that can be used to assess the abuse deterrence of different opioid formulations. Because of the many types of individuals who may be exposed to opioids, an opioid formulation will need to be studied in several populations using various study designs to determine its abuse-deterrent capabilities. It is recommended that the research conducted to evaluate abuse deterrence should include studies assessing: (1) abuse liability, (2) the likelihood that opioid abusers will find methods to circumvent the deterrent properties of the formulation, (3) measures of misuse and abuse in randomized clinical trials involving pain patients with both low risk and high risk of abuse, and (4) postmarketing epidemiological studies.

Issues in long-term opioid therapy: unmet needs, risks, and solutions

Both chronic pain and prescription opioid abuse are prevalent and exact a high toll on patients, physicians, and society. Health care professionals must balance aggressive treatment of chronic pain with the need to minimize the risks of opioid abuse, misuse, and diversion. A thorough, ongoing assessment can help fashion a multimodal therapeutic plan, stratify patients by risk, and identify those who may exhibit aberrant behaviors after receiving opioid therapy. Appropriate safeguards (eg, urine drug screens, pill counts) may be used when necessary. Because not all aberrant behaviors have the same origins or implications, physicians must consider a differential diagnosis and tailor therapy accordingly. Opioid formulations designed to deter and resist abuse are currently in late-stage clinical development and address some but not all aspects of inappropriate opioid use. By incorporating physical and pharmacological barriers to obtaining the euphoric effects of opioids, these novel formulations may minimize problematic opioid use. The formulations use a variety of strategies, for example, combining opioids with naltrexone or niacin or incorporating the opioid in a high-viscosity matrix designed to resist physical and chemical extraction. Nonopioid medications as well as cognitive, behavioral, and interventional techniques should be considered for all patients with chronic pain, particularly for those who are unable to safely take their opioids in a structured fashion. The aim of this article was to help physicians prescribe opioid medications safely and successfully to patients who need them. A PubMed literature search was conducted using the keywords risk management, assessment, aberrant behavior, addiction, prescription abuse, and abuse-deterrent.

Internet-based survey of nonmedical prescription opioid use in the United States

INTRODUCTION

Prescription opioid misuse is a growing problem in the United States. There are limited data to illuminate the nature of this issue. The Internet seems to be a novel approach in surveying populations of opioid users. An Internet-based survey of nonmedical opioid users visiting informational drug websites was used to measure rates of nonmedical use and characterize users.

METHODS

The prescription opioid module of the Addiction Severity Index Multimedia Version Connect was adapted to include variables such as favorite opioid. Links to the survey were posted on an informational drug website. Nonmedical use rates for KADIAN (morphine sulfate extended-release tablets), OxyContin (oxycodone HCl controlled-release tablets), Vicodin (hydrocodone bitartrate and acetaminophen tablets), and product-classes (morphine ER, oxycodone ER, and hydrocodone) were calculated. Descriptive statistics were calculated for remaining questions.

RESULTS

During a 1-month recruitment period, 896 valid individuals completed the survey. Majority were white (78.3%) and male (72.4%). Participants were less likely to have used KADIAN in the past 30 days compared with OxyContin (P<0.0001) and Vicodin (P=0.0021). Additionally, participants were less likely to have used morphine ER in the previous 30 days than either oxycodone ER (P<0.0001) or hydrocodone (P<0.0001). Among OxyContin, Vicodin, and KADIAN users, OxyContin (43.8%), Dilaudid (15.6%), and fentanyl (9.4%) were the top 3 favorite opioids.

DISCUSSION

This project demonstrates the feasibility of conducting product-specific, online surveys with rapid recruitment of participants from websites. This approach differentiates rates of nonmedical use of specific prescription opioids and provides other insights into individuals who nonmedically use opioids.

Challenges in the development of prescription opioid abuse-deterrent formulations

Opioid analgesics remain the cornerstone of effective management for moderate-to-severe pain. In the face of persistent lack of access to opioids by patients with legitimate pain problems, the rate of prescription opioid abuse in the United States has escalated over the past 15 years. Abuse-deterrent opioid products can play a central role in optimizing the risk-benefit ratio of opioid analgesics--if these products can be developed cost-effectively without compromising efficacy or creating new safety issues for the target treatment population. The development of scientific methods for assessing prescription opioid abuse potential remains a critical and challenging step in determining whether a claim of abuse deterrence for a new opioid product is indeed valid and will thus be accepted by the medical, regulatory, and reimbursement communities. To explore this and other potential impediments to the development of prescription opioid abuse-deterrent formulations, a panel of experts on opioid abuse and diversion from academia, industry, and governmental agencies participated in a Tufts Health Care Institute-supported symposium held on October 27 and 28, 2005, in Boston, MA. This manuscript captures the main consensus opinions of those experts, and also information gleaned from a review of the relevant published literature, to identify major impediments to the development of opioid abuse-deterrent formulations and offer strategies that may accelerate their commercialization.