Development of Ternary Amorphous Solid Dispersions Manufactured by Hot-Melt Extrusion and Spray-Drying─Comparison of In Vitro and In Vivo Performance.

Producing amorphous solid dispersions (ASDs) by hot-melt extrusion (HME) is favorable from an economic and ecological perspective but also limited to thermostable active pharmaceutical ingredients (APIs). A potential technology shift from spray-drying to hot-melt extrusion at later stages of drug product development is a desirable goal, however bearing the risk of insufficient comparability of the in vitro and in vivo performance of the final dosage form. Hot-melt extrusion was performed using API/polymer/surfactant mixtures with hydroxypropyl methylcellulose acetate succinate (HPMCAS) as the polymer and evaluated regarding the extrudability of binary and ternary amorphous solid dispersions (ASDs). Additionally, spray-dried ASDs were produced, and solid-state properties were compared to the melt-extruded ASDs. Tablets were manufactured of a ternary ASD lead candidate comparing their in vitro dissolution and in vivo performance. The extrudability of HPMCAS was improved by adding a surfactant as plasticizer, thereby lowering the high melt-viscosity. d-α-Tocopheryl polyethylene glycol succinate (TPGS) as surfactant showed the most similar solid-state properties between spray-dried and extruded ASDs compared to those of poloxamer 188 and sodium dodecyl sulfate. The addition of TPGS, however, barely affected API/polymer interactions. The in vitro dissolution experiment and in vivo dog study revealed a higher drug release of tablets manufactured from the spray-dried ASD compared to the melt-extruded ASD; this was attributed to the different particle size. We could further demonstrate that the drug release can be controlled by adjusting the particle size of melt-extruded ASDs leading to a similar release profile compared to tablets containing the spray-dried dispersion, which confirmed the feasibility of a technology shift from spray-drying to HME upon drug product development.

Insights into Factors Affecting Ethylene-Vinyl Acetate Copolymer Crystallinity in Islatravir Implant.

Islatravir, a highly potent nucleoside reverse transcriptase translocation inhibitor (NRTTI) for the treatment of HIV, has great potential to be formulated as ethylene-vinyl acetate (EVA) copolymer-based implants via hot melt extrusion. The crystallinity of EVA determines its physical and rheological properties and may impact the drug-eluting implant performance. Herein, we describe the systematic analysis of factors affecting the EVA crystallinity in islatravir implants. Differential scanning calorimetry (DSC) on EVA and solid-state NMR revealed drug loading promoted EVA crystallization, whereas BaSO4 loading had negligible impact on EVA crystallinity. The sterilization through γ-irradiation appeared to significantly impact the EVA crystallinity and surface characteristics of the implants. Furthermore, DSC analysis of thin implant slices prepared with an ultramicrotome indicated that the surface layer of the implant was more crystalline than the core. These findings provide critical insights into factors affecting the crystallinity, mechanical properties, and physicochemical properties of the EVA polymer matrix of extruded islatravir implants.

Development of Amorphous Solid Dispersion Sustained-Release Formulations with Polymer Composite Matrix-Regulated Stable Release Plateaus.

PURPOSE: This study was designed to develop ibuprofen (IBU) sustained-release amorphous solid dispersion (ASD) using polymer composites matrix with drug release plateaus for stable release and to further reveal intrinsic links between polymer' matrix ratios and drug release behaviors. METHODS: Hydrophilic polymers and hydrophobic polymers were combined to form different composite matrices in developing IBU ASD formulations by hot melt extrusion technique. The intrinsic links between the mixed polymer matrix ratio and drug dissolution behaviors was deeply clarified from the dissolution curves of hydrophilic polymers and swelling curves of composite matrices, and intermolecular forces among the components in ASDs. RESULTS: IBU + ammonio methacrylate copolymer type B (RSPO) + poly(1-vinylpyrrolidone-co-vinyl acetate) (PVP VA64) physical mixtures presented unstable release behaviors with large error bars due to inhomogeneities at the micrometer level. However, IBU-RSPO-PVP VA64 ASDs showed a "dissolution plateau phenomenon", i.e., release behaviors of IBU in ASDs were unaffected by polymer ratios when PVP VA64 content was 35% ~ 50%, which could reduce risks of variations in release behaviors due to fluctuations in prescriptions/processes. The release of IBU in ASDs was simultaneously regulated by the PVP VA64-mediated "dissolution" and RSPO-PVP VA64 assembly-mediated "swelling". Radial distribution function suggested that similar intermolecular forces between RSPO and PVP VA64 were key mechanisms for the "dissolution plateau phenomenon" in ASDs at 35% ~ 50% of PVP VA64. CONCLUSIONS: This study provided ideas for developing ASD sustained-release formulations with stable release plateau modulated by polymer combinations, taking full advantages of simple process/prescription, ease of scale-up and favorable release behavior of ASD formulations.

Preparation and Evaluation of Clarithromycin Taste-Masking Dry Suspension Using Hot Melt Extrusion Based on Solid Dispersion Technology.

Clarithromycin (CLA) is the preferred drug for treating respiratory infections in pediatric patients, but it has the drawbacks of extreme bitterness and poor water solubility. The purpose of this study was to improve solubility and mask the extreme bitterness of CLA. We use Hot Melt Extrusion (HME) to convert CLA and Eudragit® E100 into Solid Dispersion (SD). Differential scanning calorimetry (DSC) and Powder X-ray diffraction (PXRD) were used to identify the crystalline form of the prepared SDs, which showed that the crystalline CLA was converted to an amorphous form. At the same time, an increase in dissolution rate was observed, which is one of the properties of SD. The results showed that the prepared SD significantly increased the dissolution rate of crystalline CLA. Subsequently, the SD of CLA was prepared into a dry suspension with excellent suspending properties and a taste-masking effect. The bitterness bubble chart and taste radar chart showed that the SD achieved the bitter taste masking of CLA. Principal components analysis (PCA) of the data generated by the electronic tongue showed that the bitter taste of CLA was significantly suppressed using the polymer Eudragit® E100. Subsequently, a dry suspension was prepared from the SD of CLA. In conclusion, this work illustrated the importance of HME for preparing amorphous SD of CLA, which can solve the problems of bitterness-masking and poor solubility. It is also significant for the development of compliant pediatric formulations.

Drug content determination of low-dosed hot-melt extruded filaments using Raman spectroscopy.

The aim of this study was to evaluate the suitability of a non-disruptive Raman spectroscopic method to quantify drug concentrations below 5 w% within a polymer matrix produced by hot-melt extrusion (HME). For calibration, praziquantel (PZQ)-polyvinylpyrrolidone-vinylacetat-copolymer (PVP-VA) mixtures were extruded. By focusing the laser light of the Raman probe to a diameter of 1 mm and implementing a self-constructed filament holder, the signal-to-noise (S/N) ratio could be reduced considerably. The obtained Raman spectra show quite high fluorescence, which is likely to be caused by dissolved pharmaceutical active ingredient (API) in the polymer matrix. For content determination, HPLC analysis was conducted as a reference method using the same filament segments. A partial least squares (PLS) model, regressing the PZQ concentrations from HPLC method analysis versus the off-line collected Raman spectra, was developed. The linear correlation for a suitable extrusion run for the production of low-dosed filaments (extrusion 1, two kneading zones) is acceptable (R2 = 0.9915) while the correlation for a extrusion set-up with low miscibility (extrusion 2; without kneading zone) is unacceptable (R2 = 0.5349). The predictive performance of the calibration model from extrusion 1 is rated by the root mean square error of estimation (RMSEE), which was 0.08%. This calibration can now be used to validate the content of low-dosed filaments during HME.

Impact of surfactant raw material variability on extrudate clarity appearance (transparency) in HME continuous manufacturing.

The appearance of an extrudate formulation was monitored during hot-melt extrusion (HME) continuous manufacturing over 3 days. The formulation matrix consisted of a polymeric component, copovidone, and a low molecular weight surfactant, polysorbate 80. Based on studies prior to the continuous manufacturing, the desired appearance of the target extrudate is translucent. Although process parameters such as feed rate and screw speed were fixed during the continuous manufacturing, the extrudate appearance changed over time from turbid to translucent. For root-cause investigation, the extrudates were analyzed offline by differential scanning calorimetry (DSC) and advanced polymer chromatography (APC™). Although the polysorbate 80 content of both turbid and translucent extrudates was within target, the glass transition temperature of the turbid extrudate was 2 °C above expected value. The observed turbidity was traced to lot-to-lot variability of the polysorbate 80 used in the continuous manufacturing, where APC™ analysis revealed that the relative content of the low molecular weight component varied from 23% to 27% in correlation with the evolution from turbid to translucent extrudates. This work stresses the importance of taking feeding material variability into account during continuous manufacturing.

Preparation of tofacitinib sustained-release tablets using hot melt extrusion technology.

This study aimed to develop a tablet that shows a drug release profile similar to the tofacitinib sustained-release tablet (Xeljanz XR®; OROS™) using hot melt extrusion technology. Tofacitinib citrate was selected as the drug. HPMCAS, HPMCP, and Kollidon VA64 were used as thermoplastic polymers to prepare a hot-melt extrudate. The extrudate was obtained from a twin screw extruder and pelletizer. The granules were compressed using a single punch press machine and then coated. TGA, DSC, XRD, FT-IR, and SEM were performed on the hot melt extrudate to understand its physicochemical properties. Dissolution tests were performed using the paddle method (USP Apparatus II). The results showed that the crystallinity state of tofacitinib changed to amorphous after the hot melt extrusion process; however, no chemical change was observed. The drug release profile was similar to that of Xeljanz XR®, which has an initial lag time owing to its OROS™ formulation; a coating process was performed to obtain a similar drug release profile. The lag time was controlled by adjusting the thickness of the coating layer. Moreover, the extrudate size and compression force during tableting did not significantly affect drug release. In conclusion, the new tofacitinib sustained-release tablet prepared using hot melt extrusion showed a drug release behavior similar to that of Xeljanz XR®.

Hot-Melt Extrusion: from Theory to Application in Pharmaceutical Formulation-Where Are We Now?

Hot-melt extrusion (HME) is a globally recognized, robust, effective technology that enhances the bioavailability of poorly soluble active pharmaceutical ingredients and offers an efficient continuous manufacturing process. The twin-screw extruder (TSE) offers an extremely resourceful customizable mixer that is used for continuous compounding and granulation by using different combinations of conveying elements, kneading elements (forward and reverse configuration), and distributive mixing elements. TSE is thus efficiently utilized for dry, wet, or melt granulation not only to manufacture dosage forms such as tablets, capsules, or granule-filled sachets, but also for designing novel formulations such as dry powder inhalers, drying units for granules, nanoextrusion, 3D printing, complexation, and amorphous solid dispersions. Over the past decades, combined academic and pharmaceutical industry collaborations have driven novel innovations for HME technology, which has resulted in a substantial increase in published articles and patents. This article summarizes the challenges and models for executing HME scale-up. Additionally, it covers the benefits of continuous manufacturing, process analytical technology (PAT) considerations, and regulatory requirements. In summary, this well-designed review builds upon our earlier publication, probing deeper into the potential of twin-screw extruders (TSE) for various new applications.

Formulation Development and Evaluation of Cannabidiol Hot-Melt Extruded Solid Self-Emulsifying Drug Delivery System for Oral Applications.

Cannabidiol (CBD) is a highly lipophilic compound with poor oral bioavailability, due to poor aqueous solubility and extensive pre-systemic metabolism. The aim of this study was to explore the potential of employing Hot Melt Extrusion (HME) technology for the continuous production of Self Emulsifying Drug Delivery Systems (SEDDS) to improve the solubility and in vitro dissolution performance of CBD. Accordingly, different placebos were processed through HME in order to obtain a lead CBD loaded solid SEDDS. Two SEDDS were prepared with sesame oil, Poloxamer 188, Gelucire®59/14, PEO N80 and Soluplus®. Moreover, Vitamin E was added as an antioxidant. The SEDDS formulations demonstrated emulsification times of 9.19 and 9.30 min for F1 and F2 respectively. The formed emulsions showed smaller droplet size ranging from 150-400 nm that could improve lymphatic uptake of CBD and reduce first pass metabolism. Both formulations showed significantly faster in vitro dissolution rate (90% for F1 and 83% for F2) compared to 14% for the pure CBD within the first hour, giving an enhanced release profile. The formulations were tested for stability over a 60-day time period at 4°C, 25°C, and 40°C. Formulation F1 was stable over the 60-day time-period at 4°C. Therefore, the continuous HME technology could replace conventional methods for processing SEDDS and improve the oral delivery of CBD for better therapeutic outcomes.

Preparation, Characterization and Evaluation of Nintedanib Amorphous Solid Dispersions with Enhanced Oral Bioavailability.

The dissolution and bioavailability challenges posed by poorly water-soluble drugs continue to drive innovation in pharmaceutical formulation design. Nintedanib (NDNB) is a typical BCS class II drug that has been utilized to treat idiopathic pulmonary fibrosis (IPF). Due to the low solubility, its oral bioavailability is relatively low, limiting its therapeutical effectiveness. It is crucial to enhance the dissolution and the oral bioavailability of NDNB. In this study, we focused on the preparation of amorphous solid dispersions (ASD) using hot melt extrusion (HME). The formulation employed Kollidon® VA64 (VA64) as the polymer matrix, blended with the NDNB at a ratio of 9:1. HME was conducted at temperatures ranging from 80 °C to 220 °C. The successful preparation of ASD was confirmed through various tests including polarized light microscopy (PLM), X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The in-vitro cumulative release of NDNB-ASD in 2 h in a pH 6.8 medium was 8.3-fold higher than that of NDNB (p < 0.0001). In a pH 7.4 medium, it was 10 times higher (p < 0.0001). In the in-vivo pharmacokinetic experiments, the area under curve (AUC) of NDNB-ASD was 5.3-fold higher than that of NDNB and 2.2 times higher than that of commercially available soft capsules (Ofev®) (p < 0.0001). There was no recrystallization after 6 months under accelarated storage test. Our study indicated that NDNB-ASD can enhance the absorption of NDNB, thus providing a promising method to improve NDNB bioavailability in oral dosages.

Role of PLGA Variability in Controlled Drug Release from Dexamethasone Intravitreal Implants.

Long-acting injectable formulations based on poly(lactide-co-glycolide) (PLGA) have been commercialized for over 30 years in at least 20 FDA-approved products. These formulations offer several advantages, including reduced dosing frequency, improved patient compliance, and maintenance of therapeutic levels of drug. Despite extensive studies, the inherent complexity of the PLGA copolymer still poses significant challenges associated with the development of generic formulations having drug release profiles equivalent to those of the reference listed drugs. In addition, small changes to PLGA physicochemical properties or the drug product manufacturing process can have a major impact on the drug release profile of these long-acting formulations. This work seeks to better understand how variability in the physicochemical properties of similar PLGAs affects drug release from PLGA solid implants using Ozurdex (dexamethasone intravitreal implant) as the model system. Four 50:50, acid-terminated PLGAs of similar molecular weights were used to prepare four dexamethasone intravitreal implants structurally equivalent to Ozurdex. The PLGAs were extensively characterized by using a variety of analytical techniques prior to implant manufacture using a continuous, hot-melt extrusion process. In vitro release testing of the four structurally equivalent implants was performed in both normal saline and phosphate-buffered saline (PBS), yielding drastically different results between the two methods. In normal saline, no differences in the release profiles were observed. In PBS, the drug release profiles were sensitive to small changes in the residual monomer content, carboxylic acid end group content, and blockiness of the polymers. This finding further underscores the need for a physiologically relevant in vitro release testing method as part of a robust quality control strategy for PLGA-based solid implant formulations.

Switch between Cocrystal and Coamorphous Forms Depending on Thermal Modulation of Hot-Melt Extrusion.

Cocrystal (CC) and coamorphous (CM) techniques have become green technologies to improve the solubility and bioavailability of water-soluble drugs. In this study, hot-melt extrusion (HME) was employed to produce CC and CM formulations of indomethacin (IMC) and nicotinamide (NIC) due to its advantages like solvent-free and large-scale manufacturing. Interestingly, for the first time, IMC-NIC CC and CM were selectively prepared depending on the barrel temperatures of HME at a constant screw speed of 20 rpm and a feed rate of 1.0 g/min. IMC-NIC CC was obtained at 105-120 °C, IMC-NIC CM was produced at 125-150 °C, and the mixture of CC and CM was obtained between 120 and 125 °C (like a door switch of CC and CM). SS NMR combined with RDF and Ebind calculations revealed the formation mechanisms of CC and CM, where strong interactions between heteromeric molecules formed at lower temperatures favored periodic molecular organization of CC, whereas discrete and weak interactions formed at higher temperatures promoted disordered molecular arrangement of CM. Additionally, IMC-NIC CC and CM showed enhanced dissolution and stability over crystalline/amorphous IMC. This study provides an easy-to-operate and environmentally friendly strategy for the flexible regulation of CC and CM formulations with different properties through modulation of the barrel temperature of HME.

Implications of Drug-Polymer Interactions on Time-Temperature-Transformation: A Tool to Assess the Crystallization Propensity in Amorphous Solid Dispersions.

The critical cooling rate (CRcrit) to prevent drug crystallization during the preparation of nifedipine amorphous solid dispersions (ASDs) was determined through the time-temperature-transformation (TTT) diagram. ASDs were prepared with polyvinylpyrrolidone, hydroxypropylmethyl cellulose acetate succinate, and poly(acrylic acid). ASDs were subjected to isothermal crystallization over a wide temperature range, and the time and temperature dependence of nifedipine crystallization onset time (tC) was determined by differential scanning calorimetry (DSC) and synchrotron X-ray diffractometry. TTT diagrams were generated for ASDs, which provided the CRcrit for the dispersions prepared with each polymer. The observed differences in CRcrit could be explained in terms of differences in the strength of interactions. Stronger drug-polymer interactions led to longer tC and decreased CRcrit. The effect of polymer concentrations (4-20% w/w) was also influenced by the strength of the interaction. The CRcrit of amorphous NIF was ∼17.5 °C/min. Addition of 20% w/w polymer resulted in a CRcrit of ∼0.05, 0.2, and 11 °C/min for the dispersions prepared with PVP, HPMCAS, and PAA, respectively.

Understanding the Effect of Nucleation in Amorphous Solid Dispersions through Time-Temperature Transformation.

In an earlier investigation, the critical cooling rate to prevent drug crystallization (CRcrit) during the preparation of nifedipine (NIF) amorphous solid dispersions (ASDs) was determined through a time-temperature transformation (TTT) diagram (Lalge et al. Mol. Pharmaceutics 2023, 20 (3), 1806-1817). The current study aims to use the TTT diagram to determine the critical cooling rate to prevent drug nucleation (CRcrit N) during the preparation of ASDs. ASDs were prepared with each polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose acetate succinate (HPMCAS). The dispersions were first stored under conditions promoting nucleation and then heated to the temperature that favors crystallization. The crystallization onset time (tC) was determined by differential scanning calorimetry and synchrotron X-ray diffractometry. TTT diagrams for nucleation were generated, which provided the critical nucleation temperature (50 °C) and the critical cooling rate to avoid nucleation (CRcrit N). The strength of the drug-polymer interactions as well as the polymer concentration affected the CRcrit N, with PVP having a stronger interaction than HPMCAS. The CRcrit of amorphous NIF was ∼17.5 °C/min. The addition of a 20% w/w polymer resulted in CRcrit of ∼0.05 and 0.2 °C/min and CRcrit N of ∼4.1 and 8.1 °C/min for the dispersions prepared with PVP and HPMCAS, respectively.

Can Continuous Manufacturing of Topical Semisolids by Hot Melt Extrusion Soon Be a Reality?

For more than five decades, pharmaceutical manufacturers have been relying heavily on batch manufacturing that is a sequential, multistep, laborious, and time-consuming process. However, late advances in manufacturing technologies have prompted manufacturers to consider continuous manufacturing (CM) is a feasible manufacturing process that encompasses fewer steps and is less tedious and quick. Global regulatory agencies are taking a proactive role to facilitate pharmaceutical industries to adopt CM that assures product quality by employing robust manufacturing technologies encountering fewer interruptions, thereby substantially reducing product failures and recalls. However, adopting innovative CM is known to pose technical and regulatory challenges. Hot melt extrusion (HME) is one such state-of-the-art enabling technology that facilitates CM of diverse pharmaceutical dosage forms, including topical semisolids. Efforts have been made to continuously manufacture semisolids by HME integrating the principles of Quality by Design (QbD) and Quality Risk Management (QRM) and deploying Process Analytical Technologies (PAT) tools. Attempts have been made to systematically elucidate the effect of critical material attributes (CMA) and critical process parameters (CPP) on product critical quality attributes (CQA) and Quality Target Product Profiles (QTPP) deploying PAT tools. The article critically reviews the feasibility of one of the enabling technologies such as HME in CM of topical semisolids. The review highlights the benefits of the CM process and challenges ahead to implement the technology to topical semisolids. Once the CM of semisolids adopting melt extrusion integrated with PAT tools becomes a reality, the process can be extended to manufacture sterile semisolids that usually involve more critical processing steps.

Influence of PLGA End Groups on the Release Profile of Dexamethasone from Ocular Implants.

The present study deals with the development of dexamethasone (DM)-loaded implants using ester end-capped Resomer RG 502 poly(lactic acid-co-glycolic acid) (PLGA) (502), acid end-capped Resomer RG 502H PLGA (502H), and a 502H:502 mixture (3:1) via hot melt extrusion (HME). The prepared intravitreal implants (20 and 40% DM loaded in each PLGA) were thoroughly investigated to determine the effect of different end-capped PLGA and drug loading on the long-term release profile of DM. The implants were characterized for solid-state active pharmaceutical ingredient (APIs) using DSC and SWAXS, water uptake during stability study, the crystal size of API in the implant matrix using hot-stage polarized light microscopy, and in vitro release profile. The kinetics of PLGA release was thoroughly investigated using quantitative 1H NMR spectroscopy. The polymorph of DM crystal was found to remain unchanged after the extrusion and stability study. However, around 3 times reduction in API particle size was observed after the HME process. The morphology and content uniformity of the RT-stored samples were found to be comparable to the initial implant samples. Interestingly, the samples (mainly 502H) stored at 40 °C and 75% RH for 30 d demonstrated marked deformation and a change in content uniformity. The rate of DM release was higher in the case of 502H samples with a higher drug loading (40% w/w). Furthermore, a simple digital in vitro DM release profile derived for the formulation containing a 3:1 ratio of 502H and 502 was comparable with the experimental release profile of the respective polymer mixture formulation. The temporal development of pores and/or voids in the course of drug dissolution, evaluated using µCT, was found to be a precursor for the PLGA release. Overall, the release profile of DM was found to be dependent on the PLGA type (independent of subtle changes in the formulation mass and diameter). However, the extent of release was found to be dependent on DM loading. Thus, the present investigation led to a thorough understanding of the physicochemical properties of different end-capped PLGAs and the underlying formulation microstructure on the release profile of a crystalline water-insoluble drug, DM, from the PLGA-based implant.

Melt Crystallization of Celecoxib-Carbamazepine Cocrystals with the Synchronized Release of Drugs.

PURPOSE: The fixed-dose combination drug products have been increasingly used to treat some complex diseases. A cocrystal containing two therapeutic components, named as a drug-drug cocrystal, is an ideal solid form to formulate as a fixed-dose combination product. The aim of the study is to prepare celecoxib-carbamazepine (CEL-CBZ) cocrystals by melt crystallization to achieve the synchronized release of drugs. METHOD: The crystal structure of the CEL-CBZ cocrystal was determined from the cocrystals harvested from melt by single crystal X-ray diffraction. The binary phase diagram and crystal growth kinetics of the CEL-CBZ cocrystal from melt were studied to optimize the process parameters of hot-melt extrusion for manufacturing large-scale cocrystals. The intrinsic dissolution rate studies were conducted to compare the dissolution profiles of drugs in the cocrystal and their individual forms. RESULT: The CEL-CBZ cocrystal crystallized in the triclinic space group with one CEL and one CBZ molecule in the asymmetric unit. The crystallization of CEL-CBZ cocrystals were observed both in the supercooled liquid and glassy state. The formation of drug-drug cocrystals significantly alter the intrinsic dissolution rates of the parent drugs to favor the synchronized release. CONCLUSION: Melt crystallization is an alternative, efficient and eco-friendly approach for preparing drug-drug cocrystals on a large scale. The synchronized drug release by drug-drug cocrystals can be used to modulate the release profiles of parent drugs in the fixed-dose combination products.

Thermal degradation of Affinisol HPMC: Optimum Processing Temperatures for Hot Melt Extrusion and 3D Printing.

PURPOSE: Affinisol HPMC HME is a new popular form of hypromellose specifically designed for the hot melt extrusion and 3D printing of pharmaceutical products. However, reports of its thermal stability include only data obtained under inert N2 atmosphere, which is not consistent with the common pharmaceutical practice. Therefore, detailed investigation of its real-life thermal stability in air is paramount for identification of potential risks and limitations during its high-temperature processing. METHODS: In this work, the Affinisol HPMC HME 15LV powder as well as extruded filaments will be investigated by means of thermogravimetry, differential scanning calorimetry and infrared spectroscopy with respect to its thermal stability. RESULTS: The decomposition in N2 was proceeded in accordance with the literature data and manufacturer's specifications: onset at ~260°C at 0.5°C·min-1, single-step mass loss of 90-95%. However, in laboratory or industrial practice, high-temperature processing is performed in the air, where oxidation-induced degradation drastically changes. The thermogravimetric mass loss in air proceeded in three stages: ~ 5% mass loss with onset at 150°C, ~ 70% mass loss at 200°C, and ~ 15% mass loss at 380°C. Diffusion of O2 into the Affinisol material was identified as the rate-determining step. CONCLUSION: For extrusion temperatures ≥170°C, Affinisol exhibits a significant degree of degradation within the 5 min extruder retention time. Hot melt extrusion of pure Affinisol can be comfortably performed below this temperature. Utilization of plasticizers may be necessary for safe 3D printing.

Hot Melt Extrusion as an Effective Process in the Development of Mucoadhesive Tablets Containing Scutellariae baicalensis radix Extract and Chitosan Dedicated to the Treatment of Oral Infections.

Hot Melt Extrusion (HME) technology was developed to obtain blends containing lyophilized Scutellariae baicalensis root extract and chitosan in order to improve the rheological properties of the obtained blends, including tableting and compressibility properties. (Hydroxypropyl)methyl cellulose (HPMC) in 3 different ratios was used as amorphous matrix formers. The systems were characterized using X-ray powder diffraction (PXRD), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflectance (FTIR-ATR), and in vitro release, permeability, and microbiological activity studies. Then, the extrudates were used to prepare tablets in order to give them the appropriate pharmaceutical form. HPMC-based systems released baicalin more slowly, resulting in delayed peaks in the acceptor fluid. This behavior can be explained by the fact that HPMC swells significantly, and the dissolved substance must have diffused through the polymer network before being released. The best tabletability properties are provided by the formulation containing the extrudate with lyophilized extract HPMC 50:50 w/w. These tablets offer a valuable baicalin release profile while maintaining good mucoadhesive properties that condition the tablet's retention in the application site and the effectiveness of therapy.

Preparation of Solid Dispersion of Polygonum Cuspidatum Extract by Hot Melt Extrusion to Enhance Oral Bioavailability of Resveratrol.

The aim of this study was to improve the solubility, bioavailability, and stability of resveratrol (RES-SD) Solid Dispersion in Polygonum cuspidatum extract (PCE) by hot melt extrusion (HME). In addition, the role of the auxiliary substances in PCE was also studied. The solid dispersion of Polygonum cuspidatum extract was prepared by hot-melt extrusion. The optimum formula was selected by single factor design and orthogonal test. The optimum formula was barrel temperature 140 °C, screw rotation speed 40 rpm/min, and the ratio of Polygonum cuspidatum extract to HPMCAS was 1:2. The dissolution test showed that PCE-SD increased the dissolution of RES from 46.75 ± 0.47% to 130.06 ± 0.12%. The pharmacokinetics curve of rats showed that PCE-SD increased AUC0-t of RES from 111,471.22 ± 11.4% to 160,458.968 ± 15.7%, indicating an approximately 1.44-fold increase in absorption. In addition, the rotation speed of PCE-SD screw is less than that of RES-SD screw. The bioavailability of PCE-SD was slightly better than that of RES-SD. PCE-SD is more hygroscopic than RES-SD. PCE-SD increased the solubility and oral bioavailability of RES. The auxiliary substances in Polygonum cuspidatum extract have influence on its preparation technology, stability, and bioavailability.