Physicochemical properties and mechanism of drug release from ethyl cellulose matrix tablets prepared by direct compression and hot-melt extrusion

Impact of Hot-Melt Extrusion on Glibenclamide's Physical and Chemical States and Dissolution Behavior: Case Studies with Three Polymer Blend Matrices

This research work dives into the complexity of hot-melt extrusion (HME) and its influence on drug stability, focusing on solid dispersions containing 30% of glibenclamide and three 50:50 polymer blends. The polymers used in the study are Ethocel Standard 10 Premium, Kollidon SR and Affinisol HPMC HME 4M. Glibenclamide solid dispersions are characterized using thermal analyses (thermogravimetric analysis (TGA) and differential scanning calorimetry), X-ray diffraction and scanning electron microscopy. This study reveals the transformation of glibenclamide into impurity A during the HME process using mass spectrometry and TGA. Thus, it enables the quantification of the extent of degradation. Furthermore, this work shows how polymer-polymer blend matrices exert an impact on process parameters, the active pharmaceutical ingredient's physical state, and drug release behavior. In vitro dissolution studies show that the polymeric matrices investigated provide extended drug release (over 24 h), mainly dictated by the polymer's chemical nature. This paper highlights how glibenclamide is degraded during HME and how polymer selection crucially affects the sustained release dynamics.

Enhancement of dissolution rate and oral bioavailability of poorly soluble drug florfenicol by using solid dispersion and effervescent disintegration technology

OBJECTIVE

Florfenicol(FF) is an excellent veterinary antibiotic, limited by poor solubility and poor bioavailability.

SIGNIFICANCE

Here in, we aimed to explore the applicability of fast disintegrating tablets compressed from Florfenicol-loaded solid dispersions (FF-SD-FDTs) to improve the dissolution rate and oral bioavailability of Florfenicol.

METHODS

Utilizing selecting appropriate preparation methods and carriers, the solid dispersions of Florfenicol (FF-SDs) were prepared by solvent evaporation and the fast disintegrating tablets (FF-SD-FDTs) were prepared by the direct compression (DC) method.

RESULTS

The tablet properties including hardness, friability, disintegration time, weight variation, etc. all met the specifications of Chinese Veterinary Pharmacopeia(CVP). FF-SD-FDTs significantly improved drug dissolution and dispersion of FF in vitro compared to florfenicol conventional tablets (FF-CTs). A pharmacokinetics study in German shepherd dogs proved the AUC0-∞ and Cmax values of FF-SD-FDTs are 1.38 and 1.38 times more than FF-CTs, respectively.

CONCLUSIONS

Overall, it can be concluded that FF-SD-FDTs with excellent disintegration and dissolution properties were successfully produced, which greatly improved the oral bioavailability of the poorly soluble drug FF, and the study provided a new idea for a broader role of FF in pet clinics.

Comparison of Osteoconductive Ability of Two Types of Cholesterol-Bearing Pullulan (CHP) Nanogel-Hydrogels Impregnated with BMP-2 and RANKL-Binding Peptide: Bone Histomorphometric Study in a Murine Calvarial Defect Model

The receptor activator of NF-κB ligand (RANKL)-binding peptide is known to accelerate bone morphogenetic protein (BMP)-2-induced bone formation. Cholesterol-bearing pullulan (CHP)-OA nanogel-crosslinked PEG gel (CHP-OA nanogel-hydrogel) was shown to release the RANKL-binding peptide sustainably; however, an appropriate scaffold for peptide-accelerated bone formation is not determined yet. This study compares the osteoconductivity of CHP-OA hydrogel and another CHP nanogel, CHP-A nanogel-crosslinked PEG gel (CHP-A nanogel-hydrogel), in the bone formation induced by BMP-2 and the peptide. A calvarial defect model was performed in 5-week-old male mice, and scaffolds were placed in the defect. In vivo μCT was performed every week. Radiological and histological analyses after 4 weeks of scaffold placement revealed that the calcified bone area and the bone formation activity at the defect site in the CHP-OA hydrogel were significantly lower than those in the CHP-A hydrogel when the scaffolds were impregnated with both BMP-2 and the RANKL-binding peptide. The amount of induced bone was similar in both CHP-A and CHP-OA hydrogels when impregnated with BMP-2 alone. In conclusion, CHP-A hydrogel could be an appropriate scaffold compared to the CHP-OA hydrogel when the local bone formation was induced by the combination of RANKL-binding peptide and BMP-2, but not by BMP-2 alone.

Role of Microstructure in Drug Release from Chitosan Amorphous Solid Dispersions

The unexpected dissolution behaviour of amorphous diflunisal-chitosan solid dispersions (kneading method) with respect to the crystalline co-evaporated systems is the starting point of this research. This work is an in-depth study of the diflunisal release behaviour from either chitosan or carboxymethylchitosan dispersions. The microstructure is not usually considered when designing this type of products; however, it is essential to understand the process of solvent penetration and subsequent drug release through a polymeric system, as has been evidenced in this study. In accordance with the kinetic data analysed, it is possible to conclude that the porous structure, conditioned by the sample preparation method, can be considered the main factor involved in diflunisal release. The low mean pore size (1-2 μm), low porosity, and high tortuosity of the amorphous kneaded products are responsible for the slow drug release in comparison with the crystalline coevaporated systems, which exhibit larger pore size (8-10 μm) and lower tortuosity. Nevertheless, all diflunisal-carboxymethylchitosan products show similar porous microstructure and overlapping dissolution profiles. The drug release mechanisms obtained can also be related to the porous structure. Fickian diffusion was the main mechanism involved in drug release from chitosan, whereas an important contribution of erosion was detected for carboxymethylchitosan systems, probably due to its high solubility.

Poly(2-alkyl-2-oxazoline)s: A polymer platform to sustain the release from tablets with a high drug loading

Sustaining the release of highly dosed APIs from a matrix tablet is challenging. To address this challenge, this study evaluated the performance of thermoplastic poly (2-alkyl-2-oxazoline)s (PAOx) as matrix excipient to produce sustained-release tablets via three processing routes: (a) hot-melt extrusion (HME) combined with injection molding (IM), (b) HME combined with milling and compression and (c) direct compression (DC). Different PAOx (co-)polymers and polymer mixtures were processed with several active pharmaceutical ingredients having different aqueous solubilities and melting temperatures (metoprolol tartrate (MPT), metformin hydrochloride (MTF) and theophylline anhydrous (THA)). Different PAOx grades were synthesized and purified by the Supramolecular Chemistry Group, and the effect of PAOx grade and processing technique on the in vitro release kinetics was evaluated. Using the hydrophobic poly (2-n-propyl-2-oxazoline) (PⁿPrOx) as a matrix excipient allowed to sustain the release of different APIs, even at a 70% (w/w) drug load. Whereas complete THA release was not achieved from the PⁿPrOx matrix over 24 ​h regardless of the processing technique, adding 7.5% w/w of the hydrophilic poly (2-ethyl-2-oxazoline) to the hydrophobic PⁿPrOx matrix significantly increased THA release, highlighting the relevance of mixing different PAOx grades. In addition, it was demonstrated that the release of THA was similar from co-polymer and polymer mixtures with the same polymer ratios. On the other hand, as the release of MTF from a PⁿPrOx matrix was fast, the more hydrophobic poly (2-sec-butyl-2-oxazoline) (P^secBuOx) was used to retard MTF release. In addition, a mixture between the hydrophilic PEtOx and the hydrophobic P^secBuOx allowed accurate tuning of the release of MTF formulations. Finally, it was demonstrated that PAOx also showed a high ability to tune the in vivo release. IM tablets containing 70% MTF and 30% P^secBuOx showed a lower in vivo bioavailability compared to IM tablets containing a low PEtOx concentration (7.5%, w/w) in combination with P^secBuOx (22.5%, w/w). Importantly, the in vivo MTF blood level from the sustained release tablets correlated well with the in vitro release profiles. In general, this work demonstrates that PAOx polymers offer a versatile formulation platform to adjust the release rate of different APIs, enabling sustained release from tablets with up to 70% w/w drug loading.

Drug-Polymers Composite Matrix Tablets: Effect of Hydroxypropyl Methylcellulose (HPMC) K-Series on Porosity, Compatibility, and Release Behavior of the Tablet Containing a BCS Class I Drug

The purpose of this research was to see how the physicochemical properties and porosity of matrix tablets containing various types of hydroxypropyl methylcellulose (HPMC) K series affected the release of propranolol hydrochloride (PNL). PNL is a class I drug (high solubility and permeability) according to the Biopharmaceutics Classification System (BCS), making it an excellent model drug used for studying extended-release drug products. The direct compression method was used to prepare the HPMC-based matrix tablets. PNL and the excipients were found to be compatible using Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC). The surfaces of all the compressed HPMC-based matrix tablets were rough, with accumulated particles and small holes. The compressed HPMC-based matrix tablet porosity was also determined by using mercury porosimetry. The compressed HPMC-based matrix tablets made of low viscosity HPMC had tiny pores (diameter < 0.01 μm). The shorter polymeric chains are more prone to deformation, resulting in a small pore proportion. The compressed HPMC-based matrix tablets sustained the release of PNL for over 12 h. The release exponent values (n), which reflect the release mechanism of the drug from the tablets, ranged from 0.476 to 0.497. These values indicated that the release was governed by anomalous transport. The compressed HPMC-based matrix tablets have the potential for a sustained release of PNL.

Customized 3D-printed hollow capsular device filled with norfloxacin-loaded micropellets for controlled-release delivery

Pharmacotherapy has become more focused on the personalized treatment of patients with various diseases. This field of pharmacology and pharmacogenomics focuses on developing drug delivery systems designed to address the unique characteristics of individual patients. Three-dimensional printing technology can be used to fabricate personalized drug delivery systems with desired release properties according to patient needs. Norfloxacin (NOR)-loaded micropellets (MPs) were fabricated and filled inside a stereolithography (SLA) 3D printing technology-mediated hollow capsular device in accordance with a standard size of 09 (8.4 mm length × 2.70 mm diameter). The prepared 3D-printed hollow capsular device filled with pristine NOR and NOR-loaded MPs were characterized in terms of both in vitro and in vivo means. MPs with the particle size distribution of 1540.0 ± 26 µm showed 95.63 ± 2.0% NOR content with pellet-shaped surface morphology. The in vitro release profile showed an initial lag phase of approximately 30 min, followed by the sustained release of NOR from MPs from the 3D-printed hollow capsular device. The pharmacokinetic profile showed prolonged T_max, AUC, and evidence of good RBA of NOR compared to pure NOR after a single oral administration in the experimental animal model. The overall results confirm the feasibility of SLA-mediated 3D printing technology for preparing customized solid oral unit dosage carriers that can be filled with pure NOR- and NOR-loaded MPs with controlled-release delivery features.

Co-spray Drying Drugs with Aqueous Polymer Dispersions (APDs)-a Systematic Review

Aqueous colloidal dispersions of water-insoluble polymers (APDs) avoid hassles associated with the use of organic solvents and offer processing advantages related to their low viscosity and short processing times. Therefore, they became the main vehicle for pharmaceutical coating of tablets and multiparticulates, a process commonly employed using pan and fluidized-bed machinery. Another interesting although less common processing approach is co-spray drying APDs with drugs in aqueous systems. It enables the manufacture of capsule- and matrix-type microspheres with controllable size and improved processing characteristics in a single step. These microspheres can be further formulated into different dosage forms. This systematic review is based on published research articles and aims to highlight the applicability and opportunities of co-spray drying drugs with APDs in drug delivery.

Physicomechanical properties and in vitro release behaviors of electrospun ibuprofen-loaded blend PEO/EC fibers

Electrospinning is a fiber manufacturing technique with the possibility of encapsulating high levels of small molecule drugs while providing controlled release rates. In this study, electrospun blend fibers were produced from polyethylene oxide (PEO) and ethyl cellulose (EC) at various compositions to encapsulate a poorly water-soluble drug of ibuprofen (IBP) at 30% loading. Microscopic evaluation showed smooth and defect-free fiber morphologies for blank and IBP-loaded PEO/EC fibers. The average fiber diameters and fiber yields suggested a potential optimization on the blend fiber composition for the electrospun drug-eluting PEO/EC fibers, where the highest average fiber diameter and fiber yield occurred at 50PEO/50EC fiber composition. Surface wettability studies demonstrated the effects on surface hydrophobicity from blend fibers of water-soluble PEO and hydrophobic EC as well as the incorporation of IBP. In addition, blend fibers containing more PEO promoted the water absorption rates through dissolution of the polymer matrix. Furthermore, results from mechanical testing of the blend fibers showed the highest fiber elastic modulus and tensile strength at fiber compositions in between 75PEO/25EC and 50PEO/50EC, corresponding to the average fiber diameter measurements. The in vitro IBP release rates demonstrated a dependence on the EC compositions supported by the surface wettability and water absorption rate studies. In general, our work demonstrated the ability to electrospin blank and IBP-loaded PEO/EC fibers with the scientific understandings of EC compositions on modulations of fiber physicomechanical properties and in vitro drug release rates. The findings from the work indicated the potential engineering and pharmaceutical applications of electrospun drug-eluting fibers for topical drug delivery.

Predicting Drug Release Rate of Implantable Matrices and Better Understanding of the Underlying Mechanisms through Experimental Design and Artificial Neural Network-Based Modelling

There is a growing interest in implantable drug delivery systems (DDS) in pharmaceutical science. The aim of the present study is to investigate whether it is possible to customize drug release from implantable DDSs through drug-carrier interactions. Therefore, a series of chemically similar active ingredients (APIs) was mixed with different matrix-forming materials and was then compressed directly. Compression and dissolution interactions were examined by FT-IR spectroscopy. Regarding the effect of the interactions on drug release kinetics, a custom-made dissolution device designed for implantable systems was used. The data obtained were used to construct models based on artificial neural networks (ANNs) to predict drug dissolution. FT-IR studies confirmed the presence of H-bond-based solid-state interactions that intensified during dissolution. These results confirmed our hypothesis that interactions could significantly affect both the release rate and the amount of the released drug. The efficiencies of the kinetic parameter-based and point-to-point ANN models were also compared, where the results showed that the point-to-point models better handled predictive inaccuracies and provided better overall predictive efficiency.

Recent Trends in Assessment of Cellulose Derivatives in Designing Novel and Nanoparticulate-Based Drug Delivery Systems for Improvement of Oral Health

Natural polymers are revolutionizing current pharmaceutical dosage forms design as excipient and gained huge importance because of significant influence in formulation development and drug delivery. Oral health refers to the health of the teeth, gums, and the entire oral-facial system that allows us to smile, speak, and chew. Since years, biopolymers stand out due to their biocompatibility, biodegradability, low toxicity, and stability. Polysaccharides such as cellulose and their derivatives possess properties like novel mechanical robustness and hydrophilicity that can be easily fabricated into controlled-release dosage forms. Cellulose attracts the dosage design attention because of constant drug release rate from the precursor nanoparticles. This review discusses the origin, extraction, preparation of cellulose derivatives and their use in formulation development of nanoparticles having multidisciplinary applications as pharmaceutical excipient and in drug delivery, as bacterial and plant cellulose have great potential for application in the biomedical area, including dentistry, protein and peptide delivery, colorectal cancer treatment, and in 3D printable dosage forms.

Study on Adsorption Performance of Benzoic Acid in Cyclocarya paliurus Extract by Ethyl Cellulose Microspheres

Polymer microspheres with inter-connecting pores are widely used as microsphere materials. In the study, the ethyl cellulose microspheres (ECM) were prepared by using the solvent-evaporation method. Based on that, a method for the separation and purification of benzoic acid from crude extract of Cyclocarya paliurus was established by the ECM and high performance liquid chromatography (HPLC). The ECM after the sorption equilibrium was desorbed by using 40% methanol as the analytical solvent. The content of benzoic acid in eluent is up to 0.0216 mg/mL, and the benzoic acid can be obtained with a high purity of 82.22%. Furthermore, the adsorption-desorption behavior of benzoic acid onto ECM was investigated. The results of adsorption kinetics of benzoic acid showed that the adsorption followed the pseudo-first-order kinetic model. The ECM was characterized by using Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and X-ray diffraction (XRD). The results showed that the ECM has a high adsorption property due to its more porous structure, phenolic hydroxyl group, and other oxygen-containing functional groups. This method and the ECM can be used stably, continuously, and efficiently to purify the benzoic acid from the methanol extract of C. paliurus on a large scale.

Chrono modulated multiple unit particulate systems (MUPS) via a continuous hot melt double extrusion technique: Investigation of the formulation and process suitability

The current study is aimed at the development of chrono modulated multiple unit particulate systems (MUPS) of nifedipine (ND) by a continuous double extrusion process. ND, a poorly soluble drug was formulated into an amorphous solid dispersion (ASD) to improve its solubility. Further, the ASD was converted into MUPS to control the drug release through a combination of pulsatile and sustained release portions. In the preparation of the ASD, the polymer HPMCAS LG was employed at different concentrations. MUPS were formulated by using Eudragit® FS100, Eudragit® RSPO, Klucel™ HF and lipids Precirol® ATO 5, Geleol™, Compritol® ATO5. The differential scanning calorimetry and powder X-ray diffraction studies of MUPS revealed the amorphous nature of ND. Scanning electron microscopy (SEM) studies depicted the surface morphology of the ASD and the gradual change in the surface of the coated MUPS during in-vitro release studies. The in-vitro drug release profiles of ASD indicated significant improvement (p < 0.05) of solubility of ND and MUPS demonstrated a combination of pulsatile and zero-order controlled release up to 12 h. Accelerated stability studies for MUPS at 40 °C/75% RH revealed the formulations were stable. These findings suggest hot melt double extrusion as a potential alternative for conventional techniques to produce MUPS.

Injection-molded capsule bodies and caps based on polymer blends for controlled drug delivery

A variety of polymer:polymer blends was used to prepare hot melt extrudates and empty capsules (bodies and caps) by injection-molding using a benchtop extruder (Babyplast). KollidonSR:inulin and Carbothane:inulin blends were investigated. The impact of the blend ratio on the water uptake and dry mass loss kinetics upon exposure to 0.1 MHCl, phosphate buffer pH6.8 and culture medium optionally inoculated with fecal samples from Inflammatory Bowel Disease (IBD) patients were studied. Hot melt extrudates were loaded with up to 60% theophylline, capsules were filled with drug powder. Increasing the inulin content led to increased water uptake and dry mass loss rates, resulting in accelerated drug release from the dosage forms, irrespective of the type of polymer blend. This can be attributed to the higher hydrophilicity/water-solubility of this polymer compared to KollidonSR and Carbothane. Interestingly, the presence of fecal samples in culture medium increased the water uptake and dry mass loss of hot melt extrudates to a certain extent, suggesting partial system degradation by bacterial enzymes. However, these phenomena did not translate into any noteworthy impact of the presence of colonic bacteria on theophylline release from the investigated extrudates or capsules. Hence, drug release can be expected to be independent of the location "small intestine vs. colon" from these dosage forms, which can be advantageous for long term release throughout the entire gastro intestinal tract.

Binder-free twin-screw melt granulation: An effective approach to manufacture high-dose API formulations

This study investigates the use of twin-screw binder-free melt granulation (BFMG) in the development of high-dose solid dose formulations for low melting point thermally stable drugs. Both ibuprofen and guaifenesin are examined. By granulating pure API powder, it is shown that BFMG can successfully be used to produce granules that contain 100% API. A design of experiments (DoE) response surface methodology was used to establish the design space for the end-product. The effects of the most relevant process variables (barrel operating temperature, powder feed rate, screw speed and screw configuration) on granule properties (outlet temperature, size distribution, morphology, flowability, compressibility, porosity) and tablet attributes (tensile strength and in-vitro dissolution) were thoroughly studied. Barrel temperature (alone or in interactions with the other variables) represented the most significant variable for both drugs since it governs the formation of granules by partial melting and subsequent agglomeration of the fed powder. Interestingly, the shear action originated by screw speed and screw configuration resulted in various significant responses depending on the drug substance, indicating that it can also be affected by the nature of the processed molecule. Flow properties were improved (i.e., lower Hausner ratio) for both drugs after formation of granules. Tabletability was also tested by preparing 600 mg tablets for all samples. Surprisingly, the resulting granules were highly compactible, requiring only 1% lubricant to form strong tablets containing 96% API and 3% disintegrant. The results also showed that tablets become harder as the granule size increased, especially for guaifenesin. As expected, in-vitro dissolution results indicated that tablets and capsules showed slightly slower dissolution rates than the granules.

High-Pressure Dielectric Studies-a Way to Experimentally Determine the Solubility of a Drug in the Polymer Matrix at Low Temperatures

In this work, we employed broad-band dielectric spectroscopy to determine the solubility limits of nimesulide in the Kollidon VA64 matrix at ambient and elevated pressure conditions. Our studies confirmed that the solubility of the drug in the polymer matrix decreases with increasing pressure, and molecular dynamics controls the process of recrystallization of the excess of amorphous nimesulide from the supersaturated drug–polymer solution. More precisely, recrystallization initiated at a certain structural relaxation time of the sample stops when a molecular mobility different from the initial one is reached, regardless of the temperature and pressure conditions. Finally, based on the presented results, one can conclude that by transposing vertically the results obtained at elevated pressures, one can obtain the solubility limit values corresponding to low temperatures. This approach was validated by the comparison of the experimentally determined points with the theoretically obtained values based on the Flory–Huggins theory.

A Biodegradable Copolyester, Poly(butylene succinate-co-ε-caprolactone), as a High Efficiency Matrix Former for Controlled Release of Drugs

A biodegradable copolyester, poly(butylene succinate-co-ε-caprolactone) (PBS_CL), was used for first time as an excipient for pharmaceutical dosage forms using direct compression and hot processing techniques (ultrasound-assisted compression (USAC) and hot melt extrusion (HME)). Robust binary systems were achieved with hot processing techniques, allowing a controlled release of the drug. With only 12% v/v of PBS_CL, controlled release forms were obtained using USAC whereas in HME over 34% v/v of excipient is necessary. Amounts over 23% v/v allowed a long-extended release for more than 72 h following diffusional kinetic. Thanks to the high melting point of theophylline and the physicochemical properties of PBS_CL selected and synthesized, the structure of the excipient inside the USAC tablets and HME filaments corresponds to a continuum medium. A percolation threshold around 23% v/v was estimated, which agrees with a continuum percolation model. The polymer shows a high excipient efficiency value using HME and USAC. A nanostructured matrix with wall thicknesses lower than 0.1 µm was obtained. This leads to a very effective coating of the drug particles by the excipient, providing a slow and reproducible release. The present study therefore supports the use of PBS_CL, for the preparation of controlled release dosage forms using hot processing techniques.

Co-processing of small molecule excipients with polymers to improve functionality

INTRODUCTION

Polymers have various applications such as binder, film coating agent, stabilizer, drug release modification, and as primary packaging materials. Recently, they have been explored in co-processing technique to improve the functionality of small molecule excipients (SMEs). Co-processing is a concept wherein two or more excipients interact at sub-particle level to provide synergy in functionality and minimize drawbacks of individual excipients.

AREA COVERED

The present review highlights the application of co-processing to improve the functionality of SMEs using polymers; physicochemical and mechanical properties of polymers for co-processing; advantages of co-processed excipients for different applications; functionality enhancement of co-processed excipients; novel concepts/methods for co-processing; mechanistic insights on co-processing and commercial products available in the market.

EXPERT OPINION

Most of the SMEs do not possess optimal multifunctional properties like flow, compressibility, compactibility, and disintegration ability, required to compensate for poorly compactable drugs. Some of these drawbacks can be overcome by co-processing of SMEs with polymers. For example, co-processing of a brittle SME and plastic material (polymer) can provide a synergistic effect and result in the generation of single entity multi-functional excipient. Besides, novel co-processed excipients generated using combinations of SMEs and polymers can also generate intellectual property rights.

Development and Characterization of Sustained-Released Donepezil Hydrochloride Solid Dispersions Using Hot Melt Extrusion Technology

The aim of this work was to develop the sustained release formulation of donepezil hydrochloride (DH) using the hot-melt extruded solid dispersion technique via the rational screening of hydrophobic carriers. Hydrophobic carriers with different physicochemical properties such as pH-independent swellability, low-permeability (Eudragit^® RS PO (E-RS)), pH-independent non-swellability (ethyl cellulose N7 (EC-N7)), and the presence of lipids (Compritol^® 888 ATO (C-888)) with or without pore-forming agents were used to achieve the sustained release profile of DH. Mannitol (MNT) was chosen as the temporary pore-forming agent. The thermal analysis showed that both the drug and C-888 preserved their crystallinity within a solid dispersion. During a dissolution test, MNT could generate pores, and the drug release rate was proportionally correlated to the MNT content. Tailoring of the ratio of C-888 and MNT in the formulations along with an appropriate extrusion temperature profile resulted in the modified release of DH, and a preferable release pattern was obtained under these conditions. C-888 was chosen for the further investigations to obtain tablets with a high integrity. The optimized tablets were compared to the marketed formulation of Aricept^® in terms of drug release profiles. The optimized formulation showed the stable and sustained release behavior of extended release profile, which was close to the release behavior of Aricept^® with good tablet characteristics. It was concluded that the hot-melt extrusion technique can be utilized for the manufacturing of DH sustained release tablets with improved tablet integrity and characteristics by co-processing the tablet excipient with DH/C-888.

Role of release modifiers to modulate drug release from fused deposition modelling (FDM) 3D printed tablets

Although hot melt extrusion (HME) has been used in combination with fused deposition modelling (FDM) three-dimensional printing (3DP), suitable feedstock materials such as polymeric filaments with optimum properties are still limited. In this study, various release modifying excipients, namely, poly(vinyl alcohol) (PVA), Soluplus®, polyethylene glycol (PEG) 6000, Eudragit® RL PO/RS PO, hydroxypropyl methylcellulose (HPMC) K4M/E10M/K100M, Kollidon® vinyl acetate 64 (VA 64)/17PF/30, were used as a release modulating tool to control the drug release from 3D printed sustained release tablets. Ibuprofen (as the model drug) and ethyl cellulose (as the polymeric matrix), along with various release modifiers, were blended and extruded into filaments through a twin-screw extruder. Then these filaments were printed into cylindrical tablets through FDM 3DP technique and their surface morphology, thermal stability, solid-state, mechanical properties, dose accuracy and drug release behaviors were investigated. The solid-state analysis of 3D printed tablets exhibited the amorphous nature of the drug dispersed in the polymer matrices. Although all these prepared filaments could be successfully printed without failing during the FDM 3DP process, the mechanical characterization showed that the filament stiffness and brittleness could be adjusted significantly by changing the type of release modifiers. Moreover, in vitro drug release studies revealed that the drug release could simply be controlled over 24 h by only changing the type of release modifiers. All ibuprofen (IBP) loaded 3D printed tablets with ethyl cellulose (EC) matrix, especially with PEG as the release modifier, showed great potential in releasing IBP in a zero-order reaction. In conclusion, all the results illustrated that the HME/FDM approach and optimized formulation compositions can be an attractive option for the development of pharmaceutical tablets and implants where adjustable drug release patterns are necessary.

Preparation and Characterization of Silver(I) Ethylcellulose Thin Films as Potential Food Packaging Materials

Ag(I)-containing ethylcellulose (EC) films suitable as antbacterial packaging materials have been prepared and fully characterized. Different preparation methods, including the use of green casting solvents, are proposed. The Ag(I) acylpyrazolonato complexes, [Ag(Q^py,CF3 )(L)], L=benzylimidazole (Bzim) and L=ethylimidazole (EtimH), used as active additives, display different modes of interactions with EC, depending on their structural features. A thorough investigation of the EC liquid-crystalline lyotropic phase and its changes with the introduction of silver additives, has been conducted, revealing either the inclusion of complex molecules into the inner structure of the EC matrix or their dispersion on its surface. Moreover, the bactericidal activity of the prepared Ag(I) films seems to be related to the interaction between silver additives and the polymeric EC matrix. Indeed, the EC-2b films show a particularly good performance even with a low silver content, with a relative bacterial killing of about 100 %. Tests for Ag(I) migration have been performed by using three food stimulants under two assay conditions. Low values of silver release are recorded, particularly at low concentration of silver content, in the case of all new prepared Ag(I) films.

Pharmacogenomic phase transition from personalized medicine to patient-centric customized delivery

Personalized medicine has been a booming area in clinical research for the past decade, in which the detailed information about the patient genotype and clinical conditions were collected and considered to optimize the therapy to prevent adverse reactions. However, the utility of commercially available personalized medicine has not yet been maximized due to the lack of a structured protocol for implementation. In this narrative review, we explain the role of pharmacogenetics in personalized medicine, next-generation personalized medicine, i.e., patient-centric personalized medicine, in which the patient's comfort is considered along with pharmacogenomics to be a primary factor. We extensively discuss the classifications, strategies, tools, and drug delivery systems that can support the implementation of patient-centric personalized medicine from an industrial perspective.

Lignocellulosic Biomass Derived Functional Materials: Synthesis and Applications in Biomedical Engineering

The pertinent issue of resources shortage arising from global climate change in the recent years has accentuated the importance of materials that are environmentally friendly. Despite the merits of current material like cellulose as the most abundant natural polysaccharide on earth, the incorporation of lignocellulosic biomass has the potential to value-add the recent development of cellulose-derivatives in drug delivery systems. Lignocellulosic biomass, with a hierarchical structure is comprised of cellulose, hemicellulose and lignin. As an excellent substrate that is renewable, biodegradable, biocompatible and chemically accessible for modified materials, lignocellulosic biomass sets forth a myriad of applications. To date, materials derived from lignocellulosic biomass have been extensively explored for new technological development and applications, such as biomedical, green electronics and energy products. In this review, chemical constituents of lignocellulosic biomass are first discussed before we critically examine the potential alternatives in the field of biomedical application. In addition, the pretreatment methods for extracting cellulose, hemicellulose and lignin from lignocellulosic biomass as well as their biological applications including drug delivery, biosensor, tissue engineering etc. are reviewed. It is anticipated there will be an increasing interest and research findings in cellulose, hemicellulose and lignin from natural resources, which help provide important directions for the development in biomedical applications.

Wood-Based Cellulose Nanofibrils: Haemocompatibility and Impact on the Development and Behaviour of Drosophila melanogaster

Wood-based cellulose nanofibrils (CNF) offer an excellent scaffold for drug-delivery formulation development. However, toxicity and haemocompatibility of the drug carrier is always an important issue. In this study, toxicity-related issues of CNF were addressed. Different doses of CNF were orally administered to Drosophila and different tests like the developmental cycle, trypan blue exclusion assay, larva crawling assay, thermal sensitivity assay, cold sensitivity assay, larval light preference test, climbing behaviour, nitroblue tetrazolium (NBT) reduction assay, adult phenotype, and adult weight were conducted to observe the impact on its development and behaviour. A haemocompatibility assay was done on the blood taken from healthy Wistar rats. In Drosophila, the abnormalities in larval development and behaviour were observed in the behavioural assays. However, the cytotoxic effect could not be confirmed by the gut staining and level of reactive oxygen species. The larvae developed into an adult without any abnormality in the phenotype. The CNF did cause loss of weight in the adult flies and did not cause much toxicity within the body since there was no phenotypic defect. Hemolysis data also suggested that CNF was safe at lower doses, as the data was well within acceptable limits. All these results suggest that cellulose nanofibres have no significant cytotoxic effects on Drosophila. However, the developmental and behavioural abnormalities suggest that CNF may act as a behavioural teratogen.

Mass-customization of oral tablets via the combination of 3D printing and injection molding

The new frontier of medicine is the personalization of treatment to match a patient's individual needs. Fused-filament fabrication (FFF) offers a platform for the personalization of drug dosage forms, but one of its chief shortcomings compared to other tablet production methods such as dry compression and wet granulation is relatively low throughput. Conversely, injection molding (IM) is a manufacturing technique for the high-volume production of parts, but in which individual part customization is both expensive and slow requiring the modification of expensive mold tooling. Mass-customization is the manufacture of custom products that match the needs of individual consumers but which are produced at the low unit cost associated with high-volume production. We successfully integrated for the first time FFF with IM in a multi-step manufacturing process for the production of custom bilayer tablets loaded with two active pharmaceutical ingredients used in the treatment of cardiovascular disease. The FFF layer was loaded with the diuretic hydrochlorothiazide, while the IM layer was loaded with lovastatin. Infill percentage was varied for the FFF layer as a means to modify drug release. The IM injection pressure was evaluated for its effect on drug release and layer-layer adhesion. The bilayer tablets obtained offered different combinations of drug release profiles, which were governed by a combination of factors, including surface area to volume ratio; IM injection volume penetration into the FFF layer; FFF infill percentage; layer tortuosity and porosity. These different parameters could be utilized to modify the individual release of both drugs from the bilayer tablet. Thus for the first time, we have demonstrated a viable method for the mass-customization of oral tablets which could hasten the rollout of personalized medicine.

Twin-screw extrusion of sustained-release oral dosage forms and medical implants

Most of published reviews of twin-screw extrusion focused on its application for enhancing the bioavailability of amorphous solid dispersions while few of them focused on its use for manufacturing sustained-release oral dosage forms and medical implants, despite the considerable interest and success this process has garnered both in academia and in the pharmaceutical industry. Compared to conventional batch processing, twin-screw extrusion offers the advantages of continuous processing and the ability to prepare oral dosage forms and medical implants that have unique physicochemical and drug release attributes. This review provides an in-depth analysis of the formulation composition and processing conditions of twin-screw extrusion and how these factors affect the drug release properties of sustained-release dosage forms. This review also illustrates the unique advantages of this process by presenting case studies of a wide variety of commercial sustained-release products manufactured using twin-screw extrusion.

PVP VA64 as a novel release-modifier for sustained-release mini-matrices prepared via hot melt extrusion

The purpose of this study was to explore poly(vinylpyrrolidone-co-vinyl acetate) (PVP VA64) as a novel release-modifier to tailor the drug release from ethylcellulose (EC)-based mini-matrices prepared via hot melt extrusion (HME). Quetiapine fumarate (QF) was selected as model drug. QF/EC/PVP VA64 mini-matrices were extruded with 30% drug loading. The physical state of QF in extruded mini-matrices was characterized using differential scanning calorimetry, X-ray powder diffraction, and confocal Raman microscopy. The release-controlled ability of PVP VA64 was investigated and compared with that of xanthan gum, crospovidone, and low-substituted hydroxypropylcellulose. The influences of PVP VA64 content and processing temperature on QF release behavior and mechanism were also studied. The results indicated QF dispersed as the crystalline state in all mini-matrices. The release of QF from EC was very slow as only 4% QF was released in 24 h. PVP VA64 exhibited the best ability to enhance the drug release as compared with other three release-modifiers. The drug release increased to 50-100% in 24 h with the addition of 20-40% PVP VA64. Increasing processing temperature slightly slowed down the drug release by decreasing free volume and pore size. The release kinetics showed good fit with the Ritger-Peppas model. The values of release exponent (n) increased as PVP VA64 is added (0.14 for pure EC, 0.41 for 20% PVP VA64, and 0.61 for 40% PVP VA64), revealing that the addition of PVP VA64 enhanced the erosion mechanism. This work presented a new polymer blend system of EC with PVP VA64 for sustained-release prepared via HME.

Evaluation of Hydrogenated Soybean Phosphatidylcholine Matrices Prepared by Hot Melt Extrusion for Oral Controlled Delivery of Water-Soluble Drugs

The aims of this study were to prepare hydrogenated soybean phosphatidylcholine (HSPC) matrices by hot melt extrusion and to evaluate resulting matrix potential to extend drug release in regard to drug loading and solubility for oral drug delivery of water-soluble drugs. The liquid crystalline nature of HSPC powder allowed its extrusion at 120°C, which was below its capillary melting point. Model drugs with a wide range of water solubilities (8, 20 and 240 mg/mL) and melting temperatures (160-270°C) were used. Extrudates with up to 70% drug loading were prepared at temperatures below the drugs' melting points. The original crystalline state of the drugs remained unchanged through the process as confirmed by XRPD and hot-stage microscopy. The time to achieve 80% release (t80) from extrudates with 50% drug loading was 3, 8 and 18 h for diprophylline, caffeine and theophylline, respectively. The effect of matrix preparation method (extrusion vs. compression) on drug release was evaluated. For non-eroding formulations, the drug release retarding properties of the HSPC matrix were mostly not influenced by the preparation method. However, with increasing drug loadings, compressed tablets eroded significantly more than extruded matrices, resulting in 2 to 11 times faster drug release. There were no signs of erosion observed in extrudates with different drugs up to 70% loadings. The mechanical robustness of HSPC extrudates was attributed to the formation of a skin-core structure and was identified as the main reason for the drug release controlling potential of the HSPC matrices produced by hot melt extrusion.

Recent Perspectives in Hot Melt Extrusion-Based Polymeric Formulations for Drug Delivery: Applications and Innovations

Hot melt extrusion (HME), a technology which mixing the advantages of solid dispersion technology and mechanical preparation, is accepted in varied applications in pharmaceutical formulations. When combined with other techniques, such as nanotechnique, three-dimensional printing, and co-extrusion, HME becomes much more multifunctional in the application of drug delivery. While in most cases, polymers employed in HME are responsible for the final property of products. The process of HME together with the selection of materials employed in HME were described briefly. In addition, the applications of HME in drug delivery and its currently status in the pharmaceutical field were also included. Some commercial products produced by HME have met the approval of FDA, indicating the commercial viability of this technique. Although showing great potential in pharmaceutical manufacturing, HME is still challenged by high temperature, shear force, and high input energy. Development of equipment, modifying the parameters, and optimization of polymeric formulations are needed for a safe, effective, and multifunctional hot melt extrusion drug delivery system. Also, wider range of combinations between HME and other techniques may provide guideline for developing multiple applications in drug delivery.

Comparison of fused-filament fabrication to direct compression and injection molding in the manufacture of oral tablets

Oral tablets are a convenient form to deliver active pharmaceutical ingredients (API) and have a high level of acceptance from clinicians and patients. There is a wide range of excipients available for the fabrication of tablets thereby offering a versatile platform for the delivery of therapeutic agents to the gastrointestinal tract. However, the geometry of tablets is limited by conventional manufacturing processes. This study aimed to compare three manufacturing processes in the production of flat-faced oral tablets using the same formulation composed of a polymer blend and caffeine as a model drug: fused-filament fabrication (FFF), direct compression (DC) and injection molding (IM). Hot-melt extrusion was used to convert a powder blend into feedstock material for FFF and IM processes, while DC was performed on the powder mixture. Tablets were produced with the same dimensions and were characterized for their physical and dissolution properties. There were statistical differences in the physical properties and drug release profiles of the tablets produced by the different manufacturing processes. DC tablets displayed immediate release, IM provided sustained release over 48 h, and FFF tablets displayed both release types depending on the printing parameters. FFF continues to demonstrate high potential as a manufacturing process for the efficient production of personalized oral tablets.

Preparation, Optimization and In vitro Evaluation of Glipizide Nanoparticles Integrated with Eudragit RS-100

BACKGROUND

Solubility is an important criterion for drug efficacy, independent of the route of administration. It also poses a major challenge for pharmaceutical industries, which are developing new pharmaceutical products, since 40% of the active substances being identified are either insoluble or poorly soluble in aqueous media.

OBJECTIVE

The objective of this study was to develop nanoformulation of glipizide drugloaded nanoparticles providing controlled release formulation.

METHOD

Nanoparticles were prepared by the solvent evaporation method. Eudragit RS100, a nonbiodegradable polymer with varying ratios was used for making the formulation. The effect of key formulation variables on the particle size and entrapment efficiency and drug loading of nanoparticles were studied by using factorial design.

RESULTS

DSC thermograms indicate that glipizide was dispersed in an amorphous state in the polymer. TEM study indicates that the nanoparticles were in spherical shape. The mean diameter was dependent on the presence of the amount of Eudragit RS100 and viscosity of the organic phase. The in vitro study showed that the cumulative drug release was from 69.52-81.44 % in 10 hrs at pH 6.8 in phosphate buffer respectively.

CONCLUSION

The developed NPs could reduce dose frequency, decrease side effects, and improve patient compliance. Using factorial design, maximum entrapment efficiency with minimum particle size could be achieved with a few experiments.

Matrix systems for oral drug delivery: Formulations and drug release

In this current article matrix formulations for oral drug delivery are reviewed. Conventional dosage forms and novel applications such as 3D printed matrices and aerogel matrices are discussed. Beside characterization, excipients and matrix forming agents are also enlisted and classified. The incorporated drug could exist in crystalline or in amorphous forms, which makes drug dissolution easily tunable. Main drug release mechanisms are detailed and reviewed to support rational design in pharmaceutical technology and manufacturing considering the fact that R&D members of the industry are forced to obtain knowledge about excipients and methods pros and cons. As innovative and promising research fields of drug delivery, 3D printed products and highly porous, low density aerogels with high specific surface area are spreading, currently limitlessly. These compositions can also be considered as matrix formulations.

New insights into process understanding of solid lipid extrusion (SLE) of extruded lipid implants for sustained protein delivery

The aim of this work is a better understanding of solid lipid extrusion (SLE) for protein depot production using a lab-scale twin-screw (tsc)-extruder. In this context, little is known about the relationship of process parameters such as extrusion temperature, screw speed, or formulation on implant characteristics. It is difficult to attribute release characteristics to only one parameter, since the release will always be influenced by a combination of parameters. In this study, we describe the use of an online pressure measurement tool which allows to characterize pressure profiles during an extrusion run. We systematically investigated the impact of various process parameters on implant properties as well as release patterns using a monoclonal antibody (mAb). Solid lipid implants (SLIs) were produced by tsc-extrusion using the low melting triglyceride H12 and the high melting triglyceride Dynasan® D118. A mAb available in a freeze-dried matrix containing hydroxypropyl-β-cyclodextrine (HP-β-CD) was used as incorporated active pharmaceutical ingredient. Extrusion temperature (33-37 °C), screw speed (40-80 rpm) and the lipid composition (30-70% of each triglyceride) were modified. Additionally, freshly extruded SLIs were ground and extruded again as a preparation technique to optimize properties of SLIs. Using the pressure monitoring tool, four characteristic phases were defined for an extrusion run. We found that both, sufficient pressure and adequately molten material, is needed to form a suitable implant. Using the double extrusion technique, release rates could substantially be slowed down without changing formulation.

Development of an automated multi-stage continuous reactive crystallization system with in-line PATs for high viscosity process

Lower E-factor was obtained in an automated multi-stage continuous reactive-crystallization system.

Melt Extrusion for a High Melting Point Compound with Improved Solubility and Sustained Release

The objective of the current study was to develop an amorphous solid dispersion for a high melting point compound, griseofulvin (GRF), with an enhanced solubility and a controlled release pattern utilizing hot melt extrusion (HME) technology. Hypromellose acetate succinate (HPMCAS, Shin-Etsu AQOAT®, medium particle size) was explored as the polymeric carrier, while hypromellose (HPMC, Metolose® SR) was chosen as the release rate control agent. GRF presented an HPMCAS grade-dependent solubility: AS-HMP > AS-MMP > AS-LMP. At 10 wt.% loading, the release of GRF was prolonged to 6 h with the incorporation of 10% HPMC 90SH-100SR, while its solubility was enhanced up to sevenfold. Fourier transform infrared spectroscopy (FT-IR) identified the H-bonding between drug and polymers. Element analysis utilizing X-ray photoelectron spectroscopy (XPS) discovered that less GRF aggregated on the surface of binary powders compared with ternary powders containing HPMC, indicating the relatively poor wettability of the latter one. The morphology of extrudates was observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), illustrating a much smoother and uniform surface of binary extrudates. Immediate release tablets including 10% super-disintegrant L-HPC were able to achieve identical dissolution profile as the powders of extrudates.

In-process rheometry as a PAT tool for hot melt extrusion

Real time measurement of melt rheology has been investigated as a Process Analytical Technology (PAT) to monitor hot melt extrusion of an Active Pharmaceutical Ingredient (API) in a polymer matrix. A developmental API was melt mixed with a commercial copolymer using a heated twin screw extruder at different API loadings and set temperatures. The extruder was equipped with an instrumented rheological slit die which incorporated three pressure transducers flush mounted to the die surface. Pressure drop measurements within the die at a range of extrusion throughputs were used to calculate rheological parameters, such as shear viscosity and exit pressure, related to shear and elastic melt flow properties, respectively. Results showed that the melt exhibited shear thinning behavior whereby viscosity decreased with increasing flow rate. Increase in drug loading and set extrusion temperature resulted in a reduction in melt viscosity. Shear viscosity and exit pressure measurements were found to be sensitive to API loading. These findings suggest that this technique could be used as a simple tool to measure material attributes in-line, to build better overall process understanding for hot melt extrusion.

Chlorhexidine sustained-release varnishes for catheter coating - Dissolution kinetics and antibiofilm properties

Catheter-associated urinary tract infections are difficult to eradicate or prevent, due to their biofilm-related nature. Chlorhexidine, a widely used antiseptic, was previously found to be effective against catheter-related biofilms. For the present study, we developed sustained-release chlorhexidine varnishes for catheter coating and evaluated their antibiofilm properties and chlorhexidine-dissolution kinetics under various conditions. The varnishes were based on ethylcellulose or ammonio methacrylate copolymer type A (Eudragit® RL). Chlorhexidine was released by diffusion from a heterogeneous matrix in the case of the ethylcellulose-based formulation, and from a homogeneous matrix in the case of Eudragit® RL. This dictated the release pattern of chlorhexidine under testing conditions: from film specimens, and from coated catheters in a static or flow-through system. Momentary saturation was observed with the flow-through system in Eudragit® RL-based coatings, an effect that might be present in vivo with other formulations as well. The coatings were retained on the catheters for at least 2weeks, and showed prolonged activity in a biological medium, including an antibiofilm effect against Pseudomonas aeruginosa. The current study demonstrates the potential of catheter coatings with sustained release of chlorhexidine in the prevention of catheter-associated urinary tract infections.