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

The impact of diluents on the compaction, dissolution, and physical stability of amorphous solid dispersion tablets

Amorphous solid dispersion (ASD) is an effective approach for enhancing the solubility, dissolution, and bioavailability of poorly water-soluble drugs. However, these metastable forms can transform into more thermodynamically stable but less soluble crystalline forms. Despite this challenge, research on processing ASDs into solid dosage forms, such as tablets, is lacking. This work aims to fill this gap by investigating the impact of common diluents on the tableting behavior, dissolution, and physical stability of ASDs composed of itraconazole and hypromellose acetate succinate. Four widely used diluents found in commercially available ASD tablets were selected for the study: microcrystalline cellulose (MCC), anhydrous lactose, starch, and mannitol. The performance of ASD tablets varied significantly depending on the diluent used. Tablets prepared with MCC exhibited higher mechanical strength than those formulated using other diluents. ASD tablets containing mannitol and lactose revealed a faster release rate than those composed of MCC or starch. Notably, the study highlighted that the physical stability of ASDs within a tablet is not solely dependent on the amount of sorbed water; crystalline diluents like lactose and mannitol were found to facilitate ASD recrystallization within a tablet. In summary, the study underscores the importance of excipient selection, considering factors such as mechanical strength, dissolution rate, and physical stability of ASD tablets. These findings offer valuable insights into the selection of excipients for downstream ASD tablet development, leading to improved manufacturability, physical stability, and the overall quality of ASD drug products.

A Chewing Study of Abuse-Deterrent Tablets Containing Polyethylene Oxide Using a Robotic Simulator

Abuse-deterrent formulations (ADFs) refer to formulation technologies aiming to deter the abuse of prescription drugs by making the dosage forms difficult to manipulate or extract the opioids. Assessments are required to evaluate the performance of the drugs through different routes including injection, ingestion, and insufflation and also when the drugs are manipulated. Chewing is the easiest and most convenient way to manipulate the drugs and deserves investigation. Chewing is one of the most complex bioprocesses, where the ingested materials are subject to periodic tooth crushing, mixed through the tongue, and lubricated and softened by the saliva. Inter- and intra-subject variations in chewing patterns may result in different chewing performances. The purpose of this study is to use a chewing simulator to assess the deterrent properties of tablets made of polyethylene oxide (PEO). The simulator can mimic human molar grinding with variable chewing parameters including molar trajectory, chewing frequency, and saliva flow rate. To investigate the effects of these parameters, the sizes of the chewed tablet particles and the chewing force were measured to evaluate the chewing performance. Thirty-four out of forty tablets were broken into pieces. The results suggested that the simulator can chew the tablets into smaller particles and that the molar trajectory and saliva flow rate had significant effect on reducing the size of the particles by analysis of variance (ANOVA) while the effect of chewing frequency was not clear. Additionally, chewing force can work as an indicator of the chewing performance.

Evaluation of tableting performance of Poly (ethylene oxide) in abuse-deterrent formulations using compaction simulation studies

Poly (ethylene oxide) (PEO) has been widely used in abuse-deterrent formulations (ADFs) to increase tablet hardness. Previous studies have shown that formulation variables such as processing conditions and particle size of PEO can affect ADF performance in drug extraction efficiency. This work aims to understand the effect of PEO grades and sources on the compaction characteristics of model ADFs. PEOs from Dow Chemical and Sumitomo Chemical with different molecular weights were examined using a Styl'One compaction simulator at slow, medium, and fast tableting speeds. Particle-size distribution, thermal behavior, tabletability, compressibility using the Heckel model, compactibility, and elastic recovery were determined and compared between the neat PEOs and model ADFs. Multivariate linear regression was performed to understand the effect of compression conditions and PEO grades and sources. Our results show that neat PEOs with high molecular weight exhibit high tabletability. The source of neat PEOs contributes to the difference in tabletability, out-die compressibility, compactibility, and elastic recovery. However, the influence of the PEO source on tabletability and compactibility decreases after adding the model drug. In our model ADFs, tablets using PEOs with high molecular weight have high crushing strength, and tablets using PEOs from Dow Chemical display low elastic recovery.

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.