Improving drug release rate, drug-polymer miscibility, printability and processability of FDM 3D-printed tablets by weak acid-base interaction

Development of vacuum compression molded tablets with rapid drug release and a comparison of dissolution profiles between molded and FDM 3D-printed tablets

In recent years, there has been much interest in the development of personalized and on-demand tablets by FDM 3D-printing of melt-extruded filaments. Alternatively, the filaments can also be converted into molded tablets. However, drug release rates from tablets produced by both methods are very slow and not amenable to immediate-release drug products. We previously reported a novel approach called acid-base supersolubilization (ABS), whereby dissolution rates of poorly water-soluble basic drugs from FDM 3D-printed tablets could be greatly increased by interaction with added weak acids. Here, we investigated whether such acid-base interaction applying the ABS principle could similarly increase drug dissolution rates from molded tablets. Haloperidol, a basic drug with low and pH-dependent solubility, was used as the model drug, and molded tablets were prepared by the vacuum compression molding (VCM), where filaments containing 1:1 and 1:2 molar ratios of haloperidol and malic acid along with Kollidon VA64 were prepared at 15 % w/w drug loading. Broken filaments were compressed into VCM tablets under a vacuum at high temperatures. The tablets thus produced gave very high pH-independent dissolution rates, with > 90 % haloperidol dissolving in 60 min. Dissolution rates were similar from both molded and FDM 3D-printed tablets, and thus, the two methods can be used interchangeably depending on the drug development needs.

Amorphous Solid Dispersion/Salt of Efavirenz: Investigating the Role of Molecular Interactions on Recrystallization and In-vitro Dissolution Performance

Efavirenz (EFZ), a BCS (Biopharmaceutical classification system) class-II/IV drug, suffers from low oral bioavailability (40-50%) and significant inter/intra-individual variability due to its low solubility and poor dissolution properties. The present investigation aimed to prepare a stable amorphous system of EFZ to improve its dissolution using the slurry method with various polymers and examine the nature of the interaction between them and its impact on the stability (recrystallization) of the formed systems and their in-vitro dissolution performance. Differential Scanning Calorimetry (DSC) and Powder X-ray Diffraction (PXRD) studies proved the formation of a complete amorphous system of EFZ with Eudragit® E100, HPMC E5, and HPMCAS-LF up to 50% drug loading. During 90 days accelerated stability studies, amorphous systems prepared using Eudragit® E100 remained stable at 50% drug loading however those prepared with HPMC E5, and HPMCAS-LF only remained stable at 25% drug loading. The ability of Eudragit® E100 based system to stabilize the drug at higher drug loading was attributed to the formation of stronger ionic interaction as revealed by the Fourier-transform infrared spectroscopy (FTIR) study. During in-vitro dissolution study, Eudragit® E100 based amorphous system generated and maintained significantly higher supersaturation compared to those prepared with HPMC E5, and HPMCAS-LF due to the formation of ionic interaction between EFZ and Eudragit® E100 as revealed by solution 1H NMR study.

Exploring the potential of mucoadhesive buccal films in geriatric medicine

As the global demographic shifts toward an aging society, the geriatric patient population is steadily increasing. These patients often suffer from comorbidities and require numerous oral medications, which can be especially challenging for dysphagic geriatric patients. Mucoadhesive buccal films (MBFs) seem promising and could reduce pill burden, simplify administration, and enable individualized drug therapy. This review aims to explore the age-related changes in the oral cavity and their impact on MBF delivery, including potential strategies to overcome these age-related barriers to drug delivery. It was observed that aging impacts the oral mucosa as well the properties of the saliva. There are several studies in the application of buccal films including the use of a wide range of permeation enhancers. The 3D printing of buccal films seems to introduce dosing flexibility to buccal film manufacturing.

3D printing of pharmaceutical dosage forms: Recent advances and applications

Three-dimensional (3D) printing, also referred to as additive manufacturing, is considered to be a game-changing technology in many industries and is also considered to have potential use cases in pharmaceutical manufacturing, especially if individualization is desired. In this review article the authors systematically researched literature published during the last 5 years (2019 - spring 2024) on the topic of 3D printed dosage forms. Besides all kinds of oral dosage forms ranging from tablets and capsules to films, pellets, etc., numerous reports were also identified on parenteral and cutaneous dosage forms and also rectal, vaginal, dental, intravesical, and ophthalmic preparations. In total, more than 500 publications were identified and grouped according to the site of administration, and an overview of the manuscripts is presented here. Furthermore, selected publications are described and discussed in more detail. The review highlights the very different approaches that are currently used in order to develop 3D printed dosage forms but also addresses remaining challenges.

PVA-based formulations as a design-technology platform for orally disintegrating film matrices

In the majority of pharmaceutical applications, polymers are employed extensively in a diverse range of pharmaceutical products, serving as indispensable components of contemporary solid oral dosage forms. A comprehensive understanding of the properties of polymers and selection the appropriate methods of characterization is essential for the design and development of novel drug delivery systems and manufacturing processes. Orally disintegrating film (ODF) formulations are considered to be a potential substitute to traditional oral dosage forms and an alternative method of drug administration for children and uncooperative adult patients, including those with swallowing difficulties. A multitude of pharmaceutical formulations with varying mechanical and biopharmaceutical properties have emerged from the modification of the original polymeric bulk. Here we propose different formulation approaches, i.e. solvent casting (SC), 3D printing (3DP), electrospinning (ES), and lyophilization (LP) that enabled us to adjust the disintegration time and the release profile of poorly water soluble haloperidol (HAL, BCS class II) from PVA (polyvinyl alcohol) based polymer films while maintaining similar hydrogel composition. In this study, the solubility of haloperidol in aqueous solution was improved by the addition of lactic acid. The prepared films were evaluated for their morphology (SEM, micro-CT), physicochemical and biopharmaceutical properties. TMDSC, TGA and PXRD were employed for extensive thermal and structural analysis of fabricated materials and their stability. These results allowed us to establish correlations between preparation technology, structural characteristics and properties of PVA films and to adapt the suitable manufacturing technique of the ODFs to achieve appropriate HAL dissolution behaviour.

Role of rheology in formulation and process design of hot melt extruded amorphous solid dispersions

Hot melt extrusion (HME) has been widely used as a continuous and highly flexible pharmaceutical manufacturing process for the production of a variety of dosage forms. In particular, HME enables preparation of amorphous solid dispersions (ASDs) which can improve bioavailability of poorly water-soluble drugs. The rheological properties of drug-polymer mixtures can significantly influence the processability of drug formulations via HME and eventually the end-use product properties such as physical stability and drug release. The objective of this review is to provide an overview of various rheological techniques and properties that can be used to evaluate the flow behavior and processability of the drug-polymer mixtures as well as formulation characteristics such as drug-polymer interactions, miscibility/solubility, and plasticization to improve the HME processability. An overview of the thermodynamics and kinetics of ASD processing by HME is also provided, as well as aspects of scale-up and process modeling, highlighting rheological properties on formulation design and process development. Overall, this review provides valuable insights into critical rheological properties which can be used as a predictive tool to optimize the HME processing conditions.

Supersolubilization and Amorphization of a Weakly Acidic Drug, Flurbiprofen, by applying Acid-Base supersolubilization (ABS) principle

Improvement in drug solubility is a major challenge for developing pharmaceutical products. It was demonstrated earlier that aqueous solubilities of weakly basic drugs could be increased greatly by interaction with weak acids that would not form salts with the drugs, and the highly concentrated solutions thus produced converted to amorphous solids upon drying. The technique was called acid-base supersolubilization (ABS). The current investigation explored whether the ABS principle could also be applied to weakly acidic drugs. By taking flurbiprofen (pKa 4.09; free acid solubility 0.011 mg/mL) as the model weakly acidic drug and tromethamine, lysine, meglumine, and NaOH as bases, it was studied which of the bases would result in ABS. While in the presence of NaOH and tromethamine, flurbiprofen converted to salts having aqueous solubility of 11-19 mg/mL, the solubility increased to > 399 mg/mL with lysine and > 358 mg/mL with meglumine, producing supersolubilization. However, crystallization of lysine salt was observed with time, followed by some decrease in solubility after reaching maximum solubility with lysine. In contrast, the supersolubilization was maintained with meglumine, and no crystallization of meglumine salt was observed. Upon drying, flurbiprofen-meglumine solutions produced amorphous materials that dissolved rapidly and produced high drug concentrations in aqueous media. Thus, the ABS principle also applies to acidic drugs depending on the weak base used.

Application of 3D printing on the design and development of pharmaceutical oral dosage forms

3D printing technologies confer an unparalleled degree of control over the material distribution on the structures they produce, which has led them to become an extremely attractive research topic in pharmaceutical dosage form development, especially for the design of personalized treatments. With fine tuning in material selection and careful design, these technologies allow to tailor not only the amount of drug administered but the biopharmaceutical behaviour of the dosage forms as well. While fused deposition modelling (FDM) is still the most studied 3D printing technology in this area, others are gaining more relevance, which has led to many new and exciting dosage forms developed during 2022 and 2023. Considering that these technologies, in time, will join the current manufacturing methods and with the ever-increasing knowledge on this topic, our review aims to explore the advantages and limitations of 3D printing technologies employed in the design and development of pharmaceutical oral dosage forms, giving special focus to the most important aspects governing the resulting drug release profiles.

Polyvinyl Alcohol, a Versatile Excipient for Pharmaceutical 3D Printing

Three-dimensional (3D) printing in the pharmaceutical field allows rapid manufacturing of a diverse range of pharmaceutical dosage forms, including personalized items. The application of this technology in dosage form manufacturing requires the judicious selection of excipients because the selected materials must be appropriate to the working principle of each technique. Most techniques rely on the use of polymers as the main material. Among the pharmaceutically approved polymers, polyvinyl alcohol (PVA) is one of the most used, especially for fused deposition modeling (FDM) technology. This review summarizes the physical and chemical properties of pharmaceutical-grade PVA and its applications in the manufacturing of dosage forms, with a particular focus on those fabricated through FDM. The work provides evidence on the diversity of dosage forms created using this polymer, highlighting how formulation and processing difficulties may be overcome to get the dosage forms with a suitable design and release profile.

3D-printed dosage forms for oral administration: a review

Oral administration is the most commonly used form of treatment due to its advantages, including high patient compliance, convenient administration, and minimal preparation required. However, the traditional preparation process of oral solid preparation has many defects. Although continuous manufacturing line that combined all the unit operations has been developed and preliminarily applied in the pharmaceutical industry, most of the currently used manufacturing processes are still complicated and discontinuous. As a result, these complex production steps will lead to low production efficiency and high quality control risk of the final product. Additionally, the large-scale production mode is inappropriate for the personalized medicines, which commonly is customized with small amount. Several attractive techniques, such as hot-melt extrusion, fluidized bed pelletizing and spray drying, could effectively shorten the process flow, but still, they have inherent limitations that are challenging to address. As a novel manufacturing technique, 3D printing could greatly reduce or eliminate these disadvantages mentioned above, and could realize a desirable continuous production for small-scale personalized manufacturing. In recent years, due to the participation of 3D printing, the development of printed drugs has progressed by leaps and bounds, especially in the design of oral drug dosage forms. This review attempts to summarize the new development of 3D printing technology in oral preparation and also discusses their advantages and disadvantages as well as potential applications.

Towards Point-of-Care Manufacturing and Analysis of Immediate-Release 3D Printed Hydrocortisone Tablets for The Treatment of Congenital Adrenal Hyperplasia

Hydrocortisone (HC) is the preferred drug in children with congenital adrenal hyperplasia due to its lower potency as well as fewer reports of side effects. Fused deposition modelling (FDM) 3D printing holds the potential to produce low-cost personalised doses for children at the point of care. However, the compatibility of the thermal process to produce immediate-release bespoke tablets for this thermally labile active is yet to be established. This work aims to develop immediate-release HC tablets using FDM 3D printing and assess drug contents as a critical quality attribute (CQA) using a compact, low-cost near-infrared (NIR) spectroscopy as a process analytical technology (PAT). The FDM 3D printing temperature (140 °C) and drug concentration in the filament (10%-15% w/w) were critical parameters to meet the compendial criteria for drug contents and impurities. Using a compact low-cost NIR spectral device over a wavelength of 900-1700 nm, the drug contents of 3D printed tablets were assessed. Partial least squares (PLS) regression was used to develop individual calibration models to detect HC content in 3D printed tablets of lower drug contents, small caplet design, and relatively complex formula. The models demonstrated the ability to predict HC concentrations over a wide concentration range (0-15% w/w), which was confirmed by HPLC as a reference method. Ultimately, the capability of the NIR model had preceding dose verification performance on HC tablets, with linearity (R² = 0.981) and accuracy (RMSECV = 0.46%). In the future, the integration of 3DP technology with non-destructive PAT techniques will accelerate the adoption of on-demand, individualised dosing in a clinical setting.