Local Use of Hydrogel with Amiodarone in Cardiac Surgery: Experiment and Translation to the Clinic

Innovative Epicardial Bigels Containing Amiodarone Hydrochloride: Pharmacotechnical and Analytical Characterization

BACKGROUND/OBJECTIVES

The search for novel ways of providing treatment also targets the development of formulations used in drug delivery. Among the important characteristics of pharmaceutical gels are their ability to penetrate membranes, their capability to offer rapid response, and their capacity to avoid the hepatic metabolization route followed by many drugs. Bigels combine the advantages of both hydrogels and oleogels, creating a biphasic system that might improve the solubility of amiodarone in water, which is otherwise poorly soluble. This study aimed to succeed in formulating stable amiodarone hydrochloride bigels (coded from ABG1-ABG6) destined for atrial application and evaluating them from a pharmacotechnical perspective.

METHODS

Three of the six initial formulations presented stability and underwent studies of spreadability, rheology, drug content, textural properties, and microbiological activity. A statistical analysis was performed on penetrometry and drug assay data.

RESULTS

The spreadability varied from 1734.07 mm2 (ABG1) to 2163.85 mm2 (ABG6), while the drug concentration ranged between 1.35 and 1.49% (w/w). The textural profile analysis highlighted superior hardness, cohesiveness, and resilience for ABG6 and higher adhesion for ABG2. Both presented pseudoplastic thixotropic behavior, while a plastic thixotropic flow was registered in the case of ABG1.

CONCLUSIONS

All three bigels are suitable for amiodarone incorporation; however, the influence of the type of ingredients chosen on the texture and properties of the formulations was reflected in the data gathered upon evaluation.

Designing Microneedle Patch for Prophylaxis of Postoperative Atrial Fibrillation

Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery, which often occurs within 30 postoperative days, especially peaking at 2-3 days. Antiarrhythmic medications such as amiodarone are recommended in clinical practice for the prophylaxis and treatment of POAF. However, conventional oral administration is hindered due to delayed drug action and high risks of systemic toxicity, and emerging localized delivery strategies suffer from a limited release duration (less than 30 days). Herein, we develop a microneedle (MN) patch for localized delivery of amiodarone to the atria in a "First Rapid and Then Sustained" dual-release mode. Specifically, this patch is composed of a needle array integrated with an amiodarone-loaded reservoir for a sustained and steady release for over 30 days; and an amiodarone-containing coating film deposited on the needle surface via the Langmuir-Blodgett technique for a rapid release at the first day. Upon this design, only one MN patch enables a higher drug accumulation in the atrial tissue at the first day than oral administration and simultaneously remains therapeutical levels for over 30 days, despite at a significantly reduced drug dosage (5.08 mg in total versus ∼10 mg per day), thereby achieving ideal preventive effects and safety in a rat model. Our findings indicate that this MN device provides a robust and efficient delivery platform for long-term prophylaxis of POAF.

Biomaterials for direct cardiac repair-A rapid scoping review 2012-2022

A plethora of biomaterials for heart repair are being tested worldwide for potential clinical application. These therapeutics aim to enhance the quality of life of patients with heart disease using various methods to improve cardiac function. Despite the myriad of therapeutics tested, only a minority of these studied biomaterials have entered clinical trials. This rapid scoping review aims to analyze literature available from 2012 to 2022 with a focus on clinical trials using biomaterials for direct cardiac repair, i.e., where the intended function of the biomaterial is to enhance the repair of the endocardium, myocardium, epicardium or pericardium. This review included neither biomaterials related to stents and valve repair nor biomaterials serving as vehicles for the delivery of drugs. Surprisingly, the literature search revealed that only 8 different biomaterials mentioned in 23 different studies out of 7038 documents (journal articles, conference abstracts or clinical trial entries) have been tested in clinical trials since 2012. All of these, intended to treat various forms of ischaemic heart disease (heart failure, myocardial infarction), were of natural origin and most used direct injections as their delivery method. This review thus reveals notable gaps between groups of biomaterials tested pre-clinically and clinically. STATEMENT OF SIGNIFICANCE: Rapid scoping review of clinical application of biomaterials for cardiac repair. 7038 documents screened; 23 studies mention 8 different biomaterials only. Biomaterials for repair of endocardium, myocardium, epicardium or pericardium. Only 8 different biomaterials entered clinical trials in the past 10 years. All of the clinically translated biomaterials were of natural origin.

Cardiac-Targeting Peptide: From Discovery to Applications

Despite significant strides in prevention, diagnosis, and treatment, cardiovascular diseases remain the number one cause of mortality in the United States, with rates climbing at an alarming rate in the developing world. Targeted delivery of therapeutics to the heart has been a lofty goal to achieve with strategies ranging from direct intra-cardiac or intra-pericardial delivery, intra-coronary infusion, to adenoviral, lentiviral, and adeno-associated viral vectors which have preference, if not complete cardio-selectivity, for cardiac tissue. Cell-penetrating peptides (CPP) are 5-30-amino-acid-long peptides that are able to breach cell membrane barriers while carrying cargoes up to several times their size, in an intact functional form. Identified nearly three decades ago, the first of these CPPs came from the HIV coat protein transactivator of transcription. Although a highly efficient CPP, its clinical utility is limited by its robust ability to cross any cell membrane barrier, including crossing the blood-brain barrier and transducing neuronal tissue non-specifically. Several strategies have been utilized to identify cell- or tissue-specific CPPs, one of which is phage display. Using this latter technique, we identified a cardiomyocyte-targeting peptide (CTP) more than a decade ago, a finding that has been corroborated by several independent labs across the world that have utilized CTP for a myriad of different purposes in pre-clinical animal models. The goal of this publication is to provide a comprehensive review of the identification, validation, and application of CTP, and outline its potential in diagnostic and therapeutic applications especially in the field of targeted RNA interference.

Pericardial Inflammatory Mediators That Can Drive Postoperative Atrial Fibrillation in Cardiac Surgery Patients

Postoperative atrial fibrillation (POAF) is a common dysrhythmia that affects a significant number of patients undergoing cardiac surgery. Many studies aim to better understand this complex postsurgical complication by analysing circulating biomarkers in patients who develop POAF. More recently, the pericardial space was shown to contain inflammatory mediators that could trigger POAF. In this review we summarise recent studies that examine the immune mediators present in the pericardial space and their potential implications for the pathophysiology of POAF in cardiac surgery patients. Ongoing research in this area should better delineate the multifactorial etiology of POAF, where specific markers may be targeted to reduce the incidence of POAF and improve outcomes for this patient population.

Application of 3D Bioprinting in Urology

Tissue engineering is an emerging field to create functional tissue components and whole organs. The structural and functional defects caused by congenital malformation, trauma, inflammation or tumor are still the major clinical challenges facing modern urology, and the current treatment has not achieved the expected results. Recently, 3D bioprinting has gained attention for its ability to create highly specialized tissue models using biological materials, bridging the gap between artificially engineered and natural tissue structures. This paper reviews the research progress, application prospects and current challenges of 3D bioprinting in urology tissue engineering.

De novo Drug Delivery Modalities for Treating Damaged Hearts: Current Challenges and Emerging Solutions

Cardiovascular disease (CVD) is the leading cause of mortality, resulting in approximately one-third of deaths worldwide. Among CVD, acute myocardial infarctions (MI) is the leading cause of death. Current treatment modalities for treating CVD have improved over the years, but the demand for new and innovative therapies has been on the rise. The field of nanomedicine and nanotechnology has opened a new paradigm for treating damaged hearts by providing improved drug delivery methods, specifically targeting injured areas of the myocardium. With the advent of innovative biomaterials, newer therapeutics such as growth factors, stem cells, and exosomes have been successfully delivered to the injured myocardial tissue, promoting improvement in cardiac function. This review focuses on three major drug delivery modalities: nanoparticles, microspheres, and hydrogels, and their potential for treating damaged hearts following an MI.