In vivo evaluation of the chitosan-based haemostatic agent Omni-stat® in porcine liver resection and in liver injury

Recent advances in biopolymer-based hemostatic materials

Hemorrhage is the leading cause of trauma-related deaths, in hospital and pre-hospital settings. Hemostasis is a complex mechanism that involves a cascade of clotting factors and proteins that result in the formation of a strong clot. In certain surgical and emergency situations, hemostatic agents are needed to achieve faster blood coagulation to prevent the patient from experiencing a severe hemorrhagic shock. Therefore, it is critical to consider appropriate materials and designs for hemostatic agents. Many materials have been fabricated as hemostatic agents, including synthetic and naturally derived polymers. However, compared to synthetic polymers, natural polymers or biopolymers, which include polysaccharides and polypeptides, have greater biocompatibility, biodegradability, and processibility. Thus, in this review, we focus on biopolymer-based hemostatic agents of different forms, such as powder, particles, sponges, and hydrogels. Finally, we discuss biopolymer-based hemostats currently in clinical trials and offer insight into next-generation hemostats for clinical translation.

The potential of chitosan-based haemostats for use in neurosurgical setting - Literature review

Haemorrhage is a major nuance in neurosurgery since blood can distort the surgeon's field of view and increase the risk of post-operative complications. Currently a variety of commercially available haemostats have been approved for use in neurosurgery, but they have caveats to their use in the brain, including, localised tissue compression, neural toxicity, induce immune reaction or form thrombus within the vessel. Thus, there is a need for haemostats that are efficacious and safe for application on brain and spinal tissue. Chitosan is a naturally occurring bio-polymer that is found on the exoskeleton of arthropods and the cell wall of fungi. Chitosan has been shown to accelerate haemostasis through a myriad of physiological pathways. These findings have led to the development of multiple chitosan-based haemostats, for use in peripheral human tissue. Although, clinical data regarding the use of chitosan-based haemostats in the brain is lacking, a range on in vivo studies have proven chitosan to be efficacious and safe in managing neurosurgical bleeds. Similarly, literature comparing chitosan-based haemostats with commercial haemostats used commonly in neurosurgery, have all demonstrated chitosan to be the superior agent. Additionally, clinical trials of chitosan-based haemostat used in peripheral tissue have all demonstrated chitosan to be safe for human use. The marriage of these findings indicates that the safety and superior efficacy of chitosan-based haemostat, makes it a potentially suitable haemostat for use in neurosurgical setting. However, further research pertaining to the clinical use of chitosan-based haemostat within the central nervous system needs to be conducted.

Recent Advances in Polymer-Based Vaginal Drug Delivery Systems

The vagina has been considered a potential drug administration route for centuries. Most of the currently marketed and investigated vaginal formulations are composed with the use of natural or synthetic polymers having different functions in the product. The vaginal route is usually investigated as an administration site for topically acting active ingredients; however, the anatomical and physiological features of the vagina make it suitable also for drug systemic absorption. In this review, the most important natural and synthetic polymers used in vaginal products are summarized and described, with special attention paid to the properties important in terms of vaginal application. Moreover, the current knowledge on the commonly applied and innovative dosage forms designed for vaginal administration was presented. The aim of this work was to highlight the most recent research directions and indicate challenges related to vaginal drug administrations. As revealed in the literature overview, intravaginal products still gain enormous scientific attention, and novel polymers and formulations are still explored. However, there are research areas that require more extensive studies in order to provide the safety of novel vaginal products.

CoolClot, a novel hemostatic agent for controlling life-threatening arterial bleeding

BACKGROUND:

Uncontrolled bleeding is the first leading cause of preventable death in the battlefield and the 2nd cause of mortality in civil accidents. Incompressible hemorrhage control is among the interventions that drastically increase the survival rate in wound individuals. We have previously shown that a certain mixture of bentonite and zeolite minerals can significantly decrease the bleeding in rats.

METHODS:

In this study, nine healthy hybrid dogs were selected and after induction of anesthesia with ether, either arterial puncture by a needle or arteriotomy was performed on both groin regions of the dogs. For control arteries (either the right or left femoral artery), only pressure by sterilized gauze was performed, while for the femoral arteries of the opposite side, our invented hemostatic agent, namely CoolClot, was topically used before applying the pressure. In the second stage of the study, to assess the coagulation time, blood samples were collected from 10 volunteer students.

RESULTS:

CoolClot significantly decreased the bleeding time in animals whose femoral arteries were cut or punctured. In the human phase of the study, the mean coagulation time in control blood samples was 253.4±44.1 seconds, whereas it was 149.5±50.0, 162.3±74.6 and 143.4±114.6 seconds, respectively in blood samples treated with bentonite, zeolite and CoolClot (P<0.05).

CONCLUSIONS:

As controlling bleeding after a life-threatening arterial damage is critical for increasing the chance of survival, the results obtained in this study indicate the significant efficacy of CoolClot in shortening the bleeding time. Our experiments also indicate that CoolClot can significantly reduce the clotting time in human blood samples.