Micro-Patterned Polystyrene Sheets as Templates for Interlinked 3D Polyelectrolyte Multilayer Microstructures

The pursuit of linear dosage in pharmacy: reservoir-based drug delivery systems from macro to micro scale

INTRODUCTION

The pursuit of linear dosage in pharmacy is essential for achieving consistent therapeutic release and enhancing patient compliance. This review provides a comprehensive summary of zero-order drug delivery systems, with a particular focus on reservoir-based systems emanated from different microfabrication technologies.

AREAS COVERED

The consideration of recent advances in drug delivery systems is given to encompass the key areas including the importance of achieving a constant drug release rate for therapeutic applications. Detailed examination of reservoir-based systems, their design, mechanisms of action and materials used are highlighted. By addressing these areas, the discussion aims to provide a thorough understanding of most recent zero-order drug delivery systems, their performance advantages and methods of their manufacturing. To ensure the complete coverage of the explored research area, modern AI-assistant tools were used to find not only the most relevant, but also connected and similar articles.

EXPERT OPINION

Future developments in reservoir-based drug delivery systems are expected to significantly enhance therapeutic effectiveness and patient outcomes through the integration of innovative materials and technologies. The fabrication of intelligent drug delivery systems that utilize sensors and feedback mechanisms can enable real-time monitoring of drug release and patient reactions.

Patterned Drug-Eluting Coatings for Tracheal Stents Based on PLA, PLGA, and PCL for the Granulation Formation Reduction: In Vivo Studies

Expandable metallic stent placement is often the only way to treat airway obstructions. Such treatment with an uncoated stent causes granulation proliferation and subsequent restenosis, resulting in the procedure’s adverse complications. Systemic administration of steroids drugs in high dosages slows down granulation tissue overgrowth but leads to long-term side effects. Drug-eluting coatings have been used widely in cardiology for many years to suppress local granulation and reduce the organism’s systemic load. Still, so far, there are no available analogs for the trachea. Here, we demonstrate that PLA-, PCL- and PLGA-based films with arrays of microchambers to accommodate therapeutic substances can be used as a drug-eluting coating through securely fixing on the surface of an expandable nitinol stent. PCL and PLA were most resistant to mechanical damage associated with packing in delivery devices and making it possible to keep high-molecular-weight cargo. Low-molecular-weight methylprednisolone sodium succinate is poorly retained in PCL- and PLGA-based microchambers after immersion in deionized water (only 9.5% and 15.7% are left, respectively). In comparison, PLA-based microchambers retain 96.3% after the same procedure. In vivo studies on rabbits have shown that effective granulation tissue suppression is achieved when PLA and PLGA are used for coatings. PLGA-based microchamber coating almost completely degrades in 10 days in the trachea, while PLA-based microchamber films partially preserve their structure. The PCL-based film coating is most stable over time, which probably causes blocking the outflow of fluid from the tracheal mucosa and the aggravation of the inflammatory process against the background of low drug concentration. Combination and variability of polymers in the fabrication of films with microchambers to retain therapeutic compounds are suggested as a novel type of drug-eluting coating.

A scalable microfluidic chamber array for sample-loss-free and bubble-proof sample compartmentalization by simple pipetting

Sample compartmentalization is a pivotal technique in many bioanalytical applications, such as multiplex polymerase chain reaction (PCR) and digital PCR (dPCR). In this study, we successfully developed a novel self-compartmentalization device containing an array of microchambers, each of which is connected to a main microchannel with three capillary burst valves (CBVs) for fluid switching and partitioning. As these CBVs can be automatically opened in a predefined sequence, an incoming solution can be spontaneously directed into the chamber and held in place without further mixing. After that, either air or oil can be loaded into the main channel to isolate each chamber completely. By optimizing the relative burst pressures of the CBVs, a 100% sample utilization rate can be achieved even using a manual pipette and air bubbles in the sample cannot interfere with the loading. In addition, the number of the microchambers in an array can be easily scaled from a few to tens of thousands. To verify the feasibility of this self-compartmentalization method, we successfully conducted mock multiplex loop-mediated isothermal amplifications (LAMP) in an array that contains 144 microchambers, proving that our design method will provide a robust and versatile platform for various sample discretization purposes in the future.

pH dependent degradation properties of lactide based 3D microchamber arrays for sustained cargo release

Encapsulation of small water soluble molecules is important in a large variety of applications, ranging from medical substance releasing implants in the field of medicine over release of catalytically active substances in the field of chemical processing to anti-corrosion agents in industry. In this work polylactic acid (PLA) based hollow-structured microchamber (MC) arrays are fabricated via one-step dip coating of a silicone rubber stamp into PLA solution. These PLA MCs are able to retain small water soluble molecules (Rhodamine B) stably entrapped within aqueous environments. It is shown, that degradation of PLA MCs strongly depends on environmental conditions like surrounding pH and follows first order degradation kinetics. This pH dependent PLA MC degradation can be utilized to control the release kinetics of encapsulated cargo.