Influence of PEGDA Molecular Weight and Concentration on the In Vitro Release of the Model Protein BSA-FITC from Photo Crosslinked Systems

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.

Sustained release of 3D printed bupropion hydrochloride tablets bearing Braille imprints for the visually impaired

3D printing has been introduced as a novel approach for the design of personalized dosage forms and support patient groups with special needs that require additional assistance for enhanced medication adherence. In this study liquid crystal display (LCD) is introduced for the development of sustained release bupropion.HCl printed tablets. The optimization of printing hydrogel inks was combined with the display of Braille patterns on the tablet surface for blind or visually impaired patients. Due to the high printing accuracy, the Braille patterns could be verified by blind patients and provide the required information. Further characterization revealed the presence of BUP in amorphous state within the photopolymerized resins. The selection of poly(ethylene glycol) (PEG)-diacrylate (PEGDA) of different molecular weights and the presence of surfactants or solubilizers disrupted the resin photopolymerization, thus controlling the BUP dissolution rates. A small batch scale-up study demonstrated the capacity of LCD to print rapidly a notable number of tablets within 24 min.

Integrating Mechanics and Bioactivity: A Detailed Assessment of Elasticity and Viscoelasticity at Different Scales in 2D Biofunctionalized PEGDA Hydrogels for Targeted Bone Regeneration

Methods for promoting and controlling the differentiation of human mesenchymal stem cells (hMSCs) in vitro before in vivo transplantation are crucial for the advancement of tissue engineering and regenerative medicine. In this study, we developed poly(ethylene glycol) diacrylate (PEGDA) hydrogels with tunable mechanical properties, including elasticity and viscoelasticity, coupled with bioactivity achieved through the immobilization of a mixture of RGD and a mimetic peptide of the BMP-2 protein. Despite the key relevance of hydrogel mechanical properties for cell culture, a standard for its characterization has not been proposed, and comparisons between studies are challenging due to the different techniques employed. Here, a comprehensive approach was employed to characterize the elasticity and viscoelasticity of these hydrogels, integrating compression testing, rheology, and atomic force microscopy (AFM) microindentation. Distinct mechanical behaviors were observed across different PEGDA compositions, and some consistent trends across multiple techniques were identified. Using a photoactivated cross-linker, we controlled the functionalization density independently of the mechanical properties. X-ray photoelectrin spectroscopy and fluorescence microscopy were employed to evaluate the functionalization density of the materials before the culturing of hMSCs on them. The cells cultured on all functionalized hydrogels expressed an early osteoblast marker (Runx2) after 2 weeks, even in the absence of a differentiation-inducing medium compared to our controls. Additionally, after only 1 week of culture with osteogenic differentiation medium, cells showed accelerated differentiation, with clear morphological differences observed among cells in the different conditions. Notably, cells on stiff but stress-relaxing hydrogels exhibited an overexpression of the osteocyte marker E11. This suggests that the combination of the functionalization procedure with the mechanical properties of the hydrogel provides a potent approach to promoting the osteogenic differentiation of hMSCs.

Toward Tunable Protein-Driven Hydrogel Lens

Despite the significant progress in protein-based materials, creating a tunable protein-activated hydrogel lens remains an elusive goal. This study leverages the synergistic relationship between protein structural dynamics and polymer hydrogel engineering to introduce a highly transparent protein-polymer actuator. By incorporating bovine serum albumin into polyethyleneglycol diacrylate hydrogels, the authors achieved enhanced light transmittance and conferred actuating capabilities to the hydrogel. Taking advantage of these features, a bilayer protein-driven hydrogel lens that dynamically modifies its focal length in response to pH changes, mimicking the adaptability of the human lens, is fabricated. The lens demonstrates durability and reproducibility, highlighting its potential for repetitive applications. This integration of protein-diverse biochemistry, folding nanomechanics, and polymer engineering opens up new avenues for harnessing the wide range of proteins to potentially propel various fields such as diagnostics, lab-on-chip, and deep-tissue bio-optics, advancing the understanding of incorporating biomaterials in the optical field.