Crush resistance and insufflation potential of poly(ethylene oxide)-based abuse deterrent formulations

Nasal absorption of oxycodone predicted using a novel computational fluid dynamics-physiologically based pharmacokinetic model

Oxycodone hydrochloride (HCl) extended release (ER) tablet is an abuse-deterrent formulation that uses a physical barrier to make it more difficult to crush tablets prior to abuse via various routes. A previously conducted in vivo pharmacokinetics (PK) study showed that particle size exhibited significant effects on PK. Here, a computational modeling study using a novel combined computational fluid dynamics and physiologically based PK model was applied to better understand the mechanisms that produce differences in PK according to particle size and formulation type for nasally insufflated oxycodone HCl immediate release (IR) and ER tablets. Dissolution data were collected using a United States Pharmacopeia (USP) Apparatus 4 to support model parameterization. The in vitro dissolution data showed that the number of powder layers in the bead-based system impacted the observed dissolution pattern for the finely milled (106-500 μm) ER formulations, but not the finely milled IR (106-500 μm) or coarsely milled ER (500-1000 μm) formulations. The model was validated via comparison of PK predictions with available in vivo PK data for finely milled (106-500 μm) IR and ER formulations in the 30 mg strength, a coarsely milled (500-1000 μm) ER formulation in the 30 mg strength, and a finely milled ER formulation in the 80 mg strength. Model predictions showed relative differences no greater than 3.3 % for maximum plasma concentration (Cmax) and 14.9 % for area under the plasma concentration time curve from time zero to the last time point, as well as absolute differences no greater than 0.8 h for time to Cmax. The residence time in the nasal cavity was predicted to be 1 h for finely milled ER formulations as compared with approximately 20 min for the finely milled IR and coarsely milled ER formulations. When differences in dissolution input data were considered, there were noticeable changes in PK predictions observed for the finely milled ER formulations, according to the different number of powder layers in the USP Apparatus 4. Overall, the results of this study suggest that biopredictive in vitro characterization of abuse deterrence via the nasal route for an oxycodone HCl ER tablet drug product may include methods to characterize dissolution and impacts of formulation on residence time in the nasal cavity.

Multidimensional opioid abuse deterrence using a nanoparticle-polymer hybrid formulation

Misuse of prescription opioid drugs is the leading cause of the opioid crisis and overdose-related death. Abuse deterrent formulations (ADFs) have been developed to discourage attempts to tamper with the formulation and alter the ingestion methods. However, abusers develop complex extraction strategies to circumvent the ADF technologies. For comprehensive deterrence of drug abuse, we develop tannic acid nanoparticles (NPs) that protect encapsulated opioids from solvent extraction and thermal challenge (crisping), complementing the existing formulation strategy to deter injection abuse. Here, we develop a hybrid ADF tablet (NP-Tab), consisting of iron-crosslinked tannic acid NPs encapsulating thebaine (model opioid compound), xanthan gum, and chitosan (gel-forming polymers), and evaluate its performance in common abuse conditions. NP-Tab tampered by crushing and suspended in aqueous solvents forms an instantaneous gel, which is difficult to pull or push through a 21-gauge needle. NPs insulate the drug from organic solvents, deterring solvent extraction. NPs also promote thermal destruction of the drug to make crisping less rewarding. However, NP-Tab releases thebaine in the simulated gastric fluid without delay, suggesting that its analgesic effect may be unaffected if consumed orally as prescribed. These results demonstrate that NP-Tab can provide comprehensive drug abuse deterrence, resisting aqueous/organic solvent extraction, injection, and crisping, while retaining its therapeutic effect upon regular usage.

PLA-PCL microsphere formulation to deter abuse of prescription opioids by smoking

Opioids are commonly prescribed across the United States (US) for pain relief, despite their highly addictive nature that often leads to abuse and overdose deaths. Abuse deterrent formulations (ADFs) for prescription opioids make the non-therapeutic use of these drugs more difficult and less satisfying. Although approximately one-third of surveyed abusers in the US reported smoking opioids, to our knowledge, no commercialized ADF effectively prevents opioid smoking. Here, we report a novel approach to deter smoking of a model prescription opioid drug, thebaine (THB), by using polymer blend microspheres (MS) comprising polylactic acid (PLA) and polycaprolactone (PCL). We utilized high-performance liquid chromatography (HPLC) and thermogravimetric analysis (TGA) to test the ability of PLA-PCL MS to limit the escape of vaporized THB. Additionally, we compared the abuse-deterrent potential of PLA-PCL MS to that of activated carbon (AC) and mesoporous silica (MPS), two materials with excellent drug-adsorbing properties. Our MS formulation was effective in reducing the amount of both active drug and thermal degradation products in the vapor generated upon heating of THB. These results support that PLA-PCL microspheres can be co-formulated in a tablet with common prescription opioids to deter their abuse via the smoking route.

Effect of Manufacturing Process on the Retention of Abuse-Deterrent Properties of PEO-Matrix Tablets

Polyethylene oxide (PEO) is a widely used polymer in the development of abuse-deterrent oral formulations. Different manufacturing processes including direct compression (DC) followed by sintering, wet granulation (WG) followed by compression and sintering, and hot melt extrusion (HME) can be used to manufacture abuse-deterrent oral drug products. Three different manufacturing processes (DC, WG, HME) were evaluated to test the retention of their abuse-deterrent features following attempts to grind the tablets or extrudates. In vitro drug release studies were conducted on 10% and 32% drug-loaded tablets/extrudates prepared using these manufacturing methods, and the release profiles from all formulations showed good extended-release properties. Drug content analysis on the granules obtained from tablets prepared by direct compression showed non-uniform drug distribution where an unexpectedly high drug content was present in the smallest size (< 250 µm) granules, sizes which are likely to be inhaled by abusers. Granules from tablets prepared by wet granulation showed improved drug distribution across all granule sizes formed after grinding. Drug content testing on the granules obtained from extrudates prepared using hot melt extrusion showed excellent drug content uniformity along with sufficient strength to resist grinding into smaller particles. The retention of the abuse-deterrent properties of a dosage form following attempts to extract or abuse the drug is an important product characteristic, and the product design, formulation components, and manufacturing processes can all play critical roles in the retention of the desired abuse-deterrent properties.

Use of Drug Release Testing to Evaluate the Retention of Abuse-Deterrent Properties of Polyethylene Oxide Matrix Tablets

Abuse-deterrent formulations (ADFs) using physical/chemical barrier approaches limit abuse by providing resistance to dosage form manipulation to limit drug extraction or altered release. Standardizing in vitro testing methods to assess the resistance to manipulation presents a number of challenges, including the variation in particle sizes resulting from the use of various tools to alter the tablet matrix (e.g., grinding, chipping, crushing). A prototype, direct-compression ADF using a sintered polyethylene oxide (PEO) matrix containing dextromethorphan, an enantiomeric form of the opioid, levorphanol, was developed to evaluate testing methodologies for retention of abuse-deterrent properties following dosage form tampering. Sintered PEO tablets were manipulated by grinding, and drug content and release were evaluated for the recovered granules. Drug content analysis revealed that higher amounts of drug were contained in the smaller size granules (< 250 μm, 190% of the theoretical amount) compared with the larger particles (> 250 μm, 55-75% of theoretical amount). Release testing was performed on various size granule fractions (> 850 μm, 500-850 μm, 250-500 μm, and < 250 μm) using USP type I (basket), type II (paddle), and type IV (flow-through) apparatus. The USP type I and type II apparatus gave highly variable release results with poor discrimination among the release rates from different size granules. The observed sticking of the hydrated granules to the baskets and paddles, agglomeration of hydrated granules within the baskets/vessels, and ongoing PEO hydration with subsequent gel formation further altered the particle size and impacted the rate of drug release. The use of a flow-through apparatus (USP type IV) resulted in improved discrimination of drug release from different size granules with less variability due to better dispersion of granules (minimal sticking and aggregation). Drug release profiles from the USP type IV apparatus showed that the larger size granules (> 500 μm) offered continued resistance to drug release following tablet manipulation, but the smaller size granules (< 500 μm) provided rapid drug release that was unhindered by the hydrated granule matrix. Since < 500-μm size particles are preferred for nasal abuse, improved direct-compression ADF formulations should minimize the formation of these smaller-sized particles following tampering to maintain the product's abuse-deterrent features.

Extended release pellets prepared by hot melt extrusion technique for abuse deterrent potential: Category-1 in-vitro evaluation

The objective of the present study was to develop extended-release (ER) hot-melt extruded (HME) abuse-deterrent pellets of acetaminophen, a model drug, by utilizing high molecular weight polyethylene oxide (PEO) and gelling agents (xanthan gum, guar gum, and gellan gum). The HME pellets were evaluated for their abuse-deterrence (AD) potential by Category-1 laboratory in-vitro evaluation parameters, including particle size reduction (PSR), small volume extraction, dissolution, viscosity, syringeability, and injectability. Further, the pellets were investigated for resistance to physical (crushing) and thermal (oven and microwave) manipulation to evaluate the strength of the AD properties. Physical manipulation studies demonstrated that the pellets were intact, extremely hard, and resistant to PSR and manipulation to bypass ER properties. Dissolution of all intact and physically manipulated pellets led to complete drug release within 8 h, and resistance to dose-dumping in 40% ethanol was observed. The drug extraction was <50% in 10 mL of ingestible and non-ingestible solvents under static, agitation, and thermal manipulation conditions with an incubation time of 30 min. The PEO/xanthan gum-based formulation showed higher viscosity, syringe and injection forces, and lower syringeable volume in all manipulation conditions compared with plain PEO pellets. These findings supported the AD potential of PEO and xanthan gum pellets against intravenous abuse.

Polyethylene Oxide (PEO) Molecular Weight Effects on Abuse-Deterrent Properties of Matrix Tablets

While polyethylene oxide (PEO)-based matrix tablets are frequently used as abuse-deterrent dosage forms, there is limited information available regarding how the selection of formulation components and manufacturing processes affect the resulting abuse-deterrent properties. The objective of the current study was to evaluate the effects of formulation and process variables on the abuse-deterrent features of PEO-containing tablets. Directly compressed tablets were prepared using three different PEO molecular weights (100,000; 900,000; and 5,000,000). As anticipated, sintering/thermal treatment above the melting point of PEO was crucial to impart crush-resistant features (tablet hardness > 500 N). In addition to the sintering temperature, the weight fraction of PEO in the tablets affected their mechanical strength, and at least 50% w/w PEO was required to impart the desired crush-resistant features. In addition, the formulation and process variables also impacted syringeability and injectability of the PEO gels formed when the tablets were hydrated to simulate attempted drug extraction. High molecular weight PEO (900,000 and 5,000,000) produced gels more resistant to syringeability and injectability compared to low molecular weight PEO (100,000). Sintering above the polymer melting point decreased PEO crystallinity after cooling, and longer sintering times resulted in PEO degradation producing lower viscosity gels with reduced resistance to syringeability and injectability. Although sintering above the melting point of PEO imparts optimal mechanical strength to the tablets, prolonged sintering durations negatively impact polymer stability and alter the resulting abuse-deterrent features of the PEO-based tablet formulations.

Effects of Drug-Polymer Interactions on Tablet Properties During the Development of Abuse-Deterrent Dosage Forms

The objective of the present study is to understand the effects of drug-PEO interactions during the thermal treatment of polyethylene oxide (PEO)-based, directly compressed, abuse-deterrent formulations (ADFs). The drugs studied were dextromethorphan HBr monohydrate, ketoprofen, promethazine HCl, and anhydrous theophylline. Thermal treatment above the melting point of PEO resulted in tablets with higher crushing strength (> 500 N). It was observed that drug-PEO interactions during thermal treatment (80°C) led to solubilization of the incorporated drug. Drugs with higher solubility in the molten PEO, when added at higher weight fractions, interfered with the process of tablet densification which led to an increase in tablet dimensions and created defects in the fused matrix. These changes resulted in the formation of a more porous matrix. Thermal treatment led to a decrease in PEO crystallinity. The decreased crystallinity led to differences in the hydration and dissolution properties of the PEO. The change in dissolution properties of PEO accompanied with the dimensional and microstructural changes resulted in a greater drug release for some of the studied drugs. In conclusion, although thermal treatment above the melting point of PEO is an efficient manufacturing process in imparting crush-resistant features, drug-PEO interactions during the thermal treatment and the impact of thermal treatment on the properties of formulation components may impact tablet properties and lead to potential performance differences.

Determining Abuse Deterrence Performance of Poly (ethylene oxide) Using a Factorial Design

Purpose: The purpose of this study was to determine the effects of thermal processing and antioxidant formulation variables on the abuse deterrence performance of a high molecular weight poly(ethylene oxide) (PEO) polymer.

Methods: A 2⁴ factorial design with one categorical factor (antioxidant type) and three continuous factors (curing time, curing temperature, % antioxidant) was used. Abuse deterrence performance was evaluated using solution viscosity, surface melting temperature, and mechanical strength. Thermal degradation of PEO powders before compaction was also studied using DSC, FTIR spectroscopy, and viscosity analysis.

Results: Our results showed that curing temperature and type of antioxidant can significantly affect the deterrence performance of PEO. The main effect plot for viscosity shows the most prominent factors affecting viscosity are curing temperature and type of antioxidant. However, curvature in the linear model obtained was not sufficient to completely describe the behavior. For surface melting temperature, butylated hydroxytoluene was associated with higher surface melting temperatures compared to ascorbic acid. Additionally, higher percent of antioxidant resulted in higher melting temperature. Particle size distribution to indicate mechanical strength showed no significant effects of tested factors. This suggests that comminution method has more prominent effect on tablet fragment size than the formulation and processing factors studied.

Conclusion: While heat confers the mechanical strength to the polymer, it can diminish its physical stability and solution state viscosity. The experimental studies showed that prolonged exposure to high temperatures, even in the presence of antioxidants, can severely hamper polymer deterrence performance in both solid and solution states.