Liquid Drug Delivery Approaches for the Treatment of Occlusive Arterial Disease: A Systematic Review

OBJECTIVE

Local Liquid drug (LLD) delivery devices have recently emerged as a novel approach to treat peripheral arterial disease. This systemic review aims to identify and evaluate the clinical utility of the most commonly used delivery devices.

METHODS

A systemic review was performed using the Medical Subjects Heading terms of "drug delivery," "liquid," "local," and "cardiovascular disease" in PubMed, Google Scholar, and Scopus.

RESULTS

Four commonly used delivery devices were identified, including (1) the Bullfrog Micro-Infusion Device, (2) the ClearWay RX Catheter, (3) the Occlusion Perfusion Catheter, and (4) the Targeted Adjustable Pharmaceutical Administration. All have shown to successfully deliver liquid therapeutic into the target lesion and have exhibited favorable safety and efficacy profiles in preclinical and clinical trials. The LLD devices have the ability to treat very long or multiple lesions with a single device, providing a more economical option. The safety profile in LLD clinical studies is also favorable in view of recent concerns regarding adverse events with crystalline-paclitaxel-coated devices.

CONCLUSION

There is clear clinical evidence to support the concept of local liquid delivery to treat occlusive arterial disease.

CLINICAL IMPACT

The 'leave nothing behind' strategy has been at the forefront of the most recent innovations in the field of interventional cardiology and vascular interventions. Although drug coated balloons have overcome limitations associated with plain old balloon angioplasty and peripheral stents, recent safety concerns and cost considerations have impacted their usage. In this review, various liquid drug delivery devices are presented, showcasing their capabilities and success in both preclinical and clinical settings. These innovative liquid delivery devices, capable of targeted delivery and their ability to be re-used for multiple treatment sites, may provide solutions for current unmet clinical needs.

Lauric acid-based thermosensitive delivery system for the treatment of head and neck squamous cell carcinoma

Traditional treatments for head and neck squamous cell carcinoma (HNSCC) such as surgery, radiation therapy, and chemotherapy, often have severe side effects. Local delivery of chemotherapeutic agents can be a promising approach to minimise systemic toxicity and improve efficacy. Lauric acid (LA), was explored as a novel injectable thermosensitive drug reservoir as a depot for sustained release of anticancer drugs to treat HNSCC. LA was characterised in terms of melting temperature and gelation time. The efficacy of LA-based drug formulations was tested in vitro in a HNSCC cell line and in vivo in a mouse model of HNSCC. LA was modified to have a melting point of 38.5 °C and a gelation time of 40 s at 37.5 °C, rendering it suitable for injection at body temperature. LA- based doxorubicin (DOXO) formulation showed slow release with a maximum of 18% release after 3 days. The in vitro study showed that LA enhanced the cytotoxic effect of DOXO. LA combined with DOXO prevented tumour progression and LA alone significantly reduced the original tumour volume compared to the untreated control group. These findings confirmed that LA can function as practical carrier for the local delivery of chemotherapeutics and provides a safe and simple strategy for the delivery of hydrophobic anticancer drugs and warrant further testing in clinical trials.

Round Window Niche Veil is Visible on High-Resolution Computed Tomography and a Predictor of Local Drug Efficacy to Inner Ear

OBJECTIVES

To determine the morphologies and effect of the round window niche veil (RWNV) on local drug delivery efficacy and develop diagnostic criteria on high-resolution computed tomography (HRCT).

METHODS

Patients diagnosed with otosclerosis, bilateral profound sensorineural hearing loss or vestibular schwannoma were enrolled from 2019 to 2022, receiving temporal bone HRCT scanning, and anatomic variations of RWMV were summarized intraoperative. For patients with vestibular schwannoma, 1 mL of dexamethasone solution (4 mg/mL) was administered via facial recess during operation, and samples of perilymph were collected to analyze. The diagnostic criteria of RWNV on HRCT were developed and verified.

RESULTS

A total of 85 patients were enrolled. RWNV was observed in 54 cases intraoperatively with an incidence of 63.5% (95% CI, 52.9%-73.0%). The median perilymph concentrations were 4.86-fold higher in the group without RWNV than with RWNV (p < 0.0001). RWNV could be visualized on HRCT with a window width of 3500-4500 HU and a window level of 300-500 HU. The characteristic features were as follows: (1) a thin soft tissue shadow could be seen at the entrance of the round window niche (RWN); (2) it was visible in at least 2 consecutive layers along the upper margin of RWN from top to bottom; (3) it was discontinuous with the adjacent bone margin. The sensitivity and specificity of the diagnostic criteria were 77.8% and 93.6%, respectively.

CONCLUSION

RWNV could reduce local dexamethasone diffusion efficacy to the inner ear, which could be diagnosed on HRCT and used as a predictor of local drug delivery efficacy to the inner ear.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:1396-1402, 2024.

Exploring the vast potentials and probable limitations of novel and nanostructured implantable drug delivery systems for cancer treatment

Conventional cancer chemotherapy regimens, albeit successful to some extent, suffer from some significant drawbacks, such as high-dose requirements, limited bioavailability, low therapeutic indices, emergence of multiple drug resistance, off-target distribution, and adverse effects. The main goal of developing implantable drug delivery systems (IDDS) is to address these challenges and maintain anti-cancer drugs directly at the intended sites of therapeutic action while minimizing inevitable side effects. IDDS possess numerous advantages over conventional drug delivery, including controlled drug release patterns, one-time drug administration, as well as loading and stabilizing poorly water-soluble chemotherapy drugs. Here, we summarized conventional and novel (three-dimensional (3D) printing and microfluidic) preparation techniques of different IDDS, including nanofibers, films, hydrogels, wafers, sponges, and osmotic pumps. These systems could be designed with high biocompatibility and biodegradability features using a wide variety of natural and synthetic polymers. We also reviewed the published data on these systems in cancer therapy with a particular focus on their release behavior. Various release profiles could be attained in IDDS, which enable predictable, adjustable, and sustained drug releases. Furthermore, multi-step or stimuli-responsive drug release could be obtained in these systems. The studies mentioned in this article have proven the effectiveness of IDDS for treating different cancer types with high prevalence, including breast cancer, and aggressive cancer types, such as glioblastoma and liver cancer. Additionally, the challenges in applying IDDS for efficacious cancer therapy and their potential future developments are also discussed. Considering the high potential of IDDS for further advancements, such as programmable release and degradation features, further clinical trials are needed to ensure their efficiency. The overall goal of this review is to expand our understanding of the behavior of commonly investigated IDDS and to identify the barriers that should be addressed in the pursuit of more efficient therapies for cancer. See also the graphical abstract(Fig. 1).

Can Erythropoietin Open a Novel Avenue for Periodontal Regeneration?

INTRODUCTION

Periodontitis is a dramatic inflammatory disease, representing vigorous interactions between specific causative pathogens and host immune responses resulting in the activation of the destructive inflammatory cascade with the subsequent irreversible destruction of the teeth-supporting apparatus.

AIM

This study aims to evaluate the effect of using erythropoietin (EPO) injectable hydrogel, as an additional therapeutic option to scaling and root planing (SRP) in the treatment of stage II periodontitis patients, and to assess its effect on the level of osteocalcin and interleukin (IL)-1β in the gingival crevicular fluid (GCF).

METHODOLOGY

A total number of 40 patients clinically diagnosed with stage II periodontitis were included. The participants were allocated into two equal groups: study and control groups. Patients in the control group received SRP, while those in the study group received SRP followed by injectable hydrogel containing EPO. Clinical parameters such as plaque index (PI), gingival index (GI), probing pocket depth (PPD), and clinical attachment level (CAL) were assessed at baseline and two months post treatment. GCF samples were collected at baseline and two months post treatment from both groups to analyze GCF IL-1β and osteocalcin levels using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Significant reductions in all tested clinical parameters were revealed in both groups in comparison to baseline values. A marked significant reduction in GCF IL-1β level was detected in the study group. However, two months post treatment, the osteocalcin level was decreased significantly in both groups.

CONCLUSION

This preliminary study shows great promise for the local application of EPO hydrogel as an adjunct to SRP for the management of stage II periodontitis.

Depolymerized Chitosan-g-[Poly(MMA-co-HEMA-cl-EGDMA)] Based Nanogels for Controlled Local Release of Bupivacaine

This study is designed to formulate and characterize chitosan-based nanogels that provide the controlled delivery of anesthetic drugs, such as bupivacaine (BPV), for effective postoperative pain management over prolonged periods of time. Drug carriers of chitosan/poly (MMA-co-HEMA-cl-EGDMA) (CsPMH) nanogels were prepared by varying the composition of comonomers such as MMA, HEMA, and redox initiator CAN. The nanogels were then characterized using FTIR, TGA, SEM, and TEM. The CsPMH nanogels showed greater encapsulation efficiencies from 43.20-91.77%. Computational studies were also conducted to evaluate the interaction between the drug and CsPMH nanoparticles. Finally, BPV-loaded nanoparticles were used to examine their in vitro release behavior. At pH 7.4, all the drug carriers displayed the "n" value around 0.7, thus the BPV release follows anomalous diffusion. Drug carrier 7 demonstrated a steady and sustained release of BPV for approximately 24 h and released about 91% of BPV, following the K-P mechanism of drug release. On the other hand, drug carrier 6 exhibited controlled release for approximately 12 h and released only 62% of BPV.

Unveiling the enigma of the blood-brain barrier in glioblastoma: current advances from preclinical and clinical studies

PURPOSE OF REVIEW

Glioblastoma (GBM), the most prevalent primary brain malignancy in adults, poses significant challenges in terms of treatment. Current therapeutic strategies for GBM patients involve maximal safe resection, followed by radiotherapy with concurrent and adjuvant temozolomide. However, despite this multimodal approach for GBM, the prognosis of GBM patients remains dismal because of their inherent primary and secondary resistances to treatments.

RECENT FINDINGS

Several molecular and cellular mechanisms, including the presence of the blood-brain barrier (BBB), contribute to these resistances. The BBB, comprising multiple layers surrounding brain vessels, acts as a barrier limiting effective drug delivery to the brain. Invasive and noninvasive tools to deliver drugs and pharmaceutical formulations locally or systemically are continuously evolving to overcome the BBB in GBM toward improving drug bioavailability in the brain and reducing systemic toxicities.

SUMMARY

Preliminary studies utilizing these approaches have demonstrated promising results in terms of safety and signals of efficacy during early-phase clinical trials. However, further work through additional clinical trials is necessary to evaluate the potential clinical benefits for GBM patients.

Preparation of Ocimum Sanctum-Based Hydrogel and Evaluation of Its Cytotoxicity: An In Vitro Study

INTRODUCTION

While traditional periodontal treatments like scaling and root planing, antibiotics, and surgical intervention remain the primary approaches, herbal medicine is continuously evolving as an alternative for the management of periodontal diseases. This study focused on the evaluation of the cytotoxicity of Ocimum sanctum (OS)-based hydrogel for its use in local drug delivery in periodontitis.

METHODS

OS-based hydrogel was prepared using 50 g of OS powder and 200 ml of ethanol, along with carboxymethyl cellulose gel and sorbitol. The prepared formulation was evaluated for its cytotoxicity by using the MTT assay, cell viability, cell morphology, and brine shrimp egg assessment.

RESULTS

Cell viability was assessed, and it was above 95% for the control and 85% for the OS hydrogel by the 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide assay. Brine shrimp egg assessment also showed a survival rate of 80% at low concentrations. The cell morphology test showed round and uniform cells growing in a monolayer shape.

CONCLUSION

The findings of this study confirmed that OS-based hydrogel is cytocompatible and, hence, can be used as a local drug delivery agent for periodontitis management, especially in resource-constrained settings where affordable and natural treatment options are highly valued.

Efficacy of Sub-Gingivally Delivered Propolis Nanoparticle in Non-Surgical Management of Periodontal Pocket: A Randomized Clinical Trial

Naturally sourced products like propolis are commonly employed for the non-surgical treatment of periodontal pockets. The use of nanoparticle formulations of these natural remedies has the potential to improve treatment outcomes. The aim of the present study was to evaluate the efficacy of sub-gingivally delivered propolis nanoparticles in the non-surgical management of periodontal pockets. Forty patients diagnosed with periodontitis presenting at least one periodontal pocket with a probing pocket depth between 4 and 6 mm were selected. Patients were randomly assigned into the control group (n = 20), which received scaling and root planing (SRP) and saline (SRP + Saline), and the test group (n = 20), which received SRP and sub-gingivally delivered propolis nanoparticles (PRO) into the periodontal pocket (SRP + PRO). The clinical parameters recorded were plaque index (PI), gingival index (GI), relative attachment loss (RAL), probing pocket depth (PPD), and bleeding on probing (BOP). They were assessed at baseline, one month, and three months post therapy. The results indicated that there was a significant improvement in clinical parameters (p < 0.05) in the test sites compared with the control sites at the end of the study. The gingival index at one month and three months was found to be significantly better in the SRP + PRO group than the SRP + Saline group, with a p value of <0.001. The BOP, PPD, and RAL showed significant improvement with the SRP + PRO group at the end of the 3-month follow-up with p values of 0.0001, 0.001, and 0.05, respectively. The subgingival delivery of propolis nanoparticles showed promising results as an adjunct to SRP in patients with periodontitis presenting periodontal pockets.

Preparation and Evaluation of Antimicrobial Property and Anti-inflammatory Activity of Fenugreek Gel Against Oral Microbes: An Invitro Study

Aim Periodontal dressings play a crucial role in periodontal surgery and dental procedures. These dressings have several functions and benefits, similar to surgical wound dressings used in other surgical contexts. Periodontal dressings protect the surgical site and control bleeding in the oral cavity as they exert pressure on tissue and blood vessels. By protecting the wound and stabilizing the tissues, periodontal dressings create an environment that encourages proper and faster healing. Recently, the use of periodontal pack has reported various postoperative discomfort to the patients. This led to the development of an interest in considering fenugreek as an alternative to periodontal dressing as it possesses various antidiabetic and hypolipidemic effects. Thus, fenugreek can be used as an alternative to periodontal dressing. The study aimed to prepare and evaluate the antimicrobial nature of fenugreek gel in oral microbes and the anti-inflammatory properties of gel with protein coagulation in egg albumin. Materials and methods The fenugreek gel preparation was done by grinding 100 g of fenugreek seeds into a powder and adding 100 ml of distilled water to the powder and then heating the mixture at 70°C for 30 minutes. Five milliliters of the fenugreek concentrate were added to an equal mixture of carboxymethyl cellulose and Carbopol which was mixed thoroughly to form a gel. The antimicrobial nature of fenugreek has been evaluated in various organisms such as Streptococcus mutans, Lactobacillus, Enterococcus faecalis, and Candida albicans whereas the anti-inflammatory property was evaluated by protein coagulation method in egg albumin. Results The results stated that the fenugreek gel at a concentration of 100 µg/ml showed a greater zone of inhibition (5.39 ± 0.05) compared with doxycycline (1.1 ± 0.08) for a high antimicrobial potential against all oral microbes. The anti-inflammatory activity of the gel by protein coagulation method in egg albumin showed greater inhibition (67.15±1.36) at 100 µg/ml of fenugreek extract when compared with aspirin (64.43±2.93). Paired t-test was done for both the properties and the p-value was less than 0.5 stating that the difference between the groups was statistically significant. Conclusion The present study showed that the fenugreek gel possesses higher antimicrobial and anti-inflammatory properties when compared with doxycycline and aspirin, respectively. Hence, fenugreek gel can be used as an alternative periodontal dressing to reduce postoperative inflammation.

Drug-loaded mucoadhesive microneedle patch for the treatment of oral submucous fibrosis

Oral submucous fibrosis is a chronic, inflammatory and potentially malignant oral disease. Local delivery of triamcinolone to lesion site is a commonly used therapy. The existing methods for local drug delivery include topical administration and submucosal injection. However, in the wet and dynamic oral microenvironment, these methods have drawbacks such as limited drug delivery efficiency and injection pain. Therefore, it is urgently needed to develop an alternative local drug delivery system with high efficiency and painlessness. Inspired by the structure of band-aid, this study proposed a novel double-layered mucoadhesive microneedle patch for transmucosal drug delivery. The patch consisted of a mucoadhesive silk fibroin/tannic acid top-layer and a silk fibroin microneedle under-layer. When applying the annealing condition for the medium content of β-sheets of silk fibroin, the microneedles in under-layer displayed both superior morphology and mechanical property. The mechanical strength of per needle (0.071N) was sufficient to penetrate the oral mucosa. Sequentially, the gelation efficiency of silk fibroin and tannic acid in top-layer was maximized as the weight ratio of tannic acid to silk fibroin reached 5:1. Moreover, in vitro results demonstrated the double-layered patch possessed undetectable cytotoxicity. The sustained release of triamcinolone was observed from the double-layered patch for at least 7 days. Furthermore, compared with other commercial buccal patches, the double-layered patch exhibited an enhanced wet adhesion strength of 37.74 kPa. In addition, ex vivo mucosal tissue penetration experiment confirmed that the double-layered patch could reach the lamina propria, ensuring effective drug delivery to the lesion site of oral submucous fibrosis. These results illustrate the promising potential of the drug-loaded mucoadhesive microneedle patch for the treatment of oral submucous fibrosis.

Therapeutic Potential of Chlorhexidine-Loaded Calcium Hydroxide-Based Intracanal Medications in Endo-Periodontal Lesions: An Ex Vivo and In Vitro Study

Endo-periodontal lesions are challenging clinical situations where both the supporting tissues and the root canal of the same tooth are infected. In the present study, chlorhexidine (CHX)-loaded calcium hydroxide (CH) pastes were used as intracanal medications (ICMs). They were prepared and tested on pathogens found in both the root canal and the periodontal pocket. Exposure to 0.5% and 1% CHX-loaded ICMs decreased the growth of Porphyromonas gingivalis and was effective in eradicating or inhibiting an Enterococcus faecalis biofilm. CH was injected into the root canal of extracted human teeth immersed in deionized water. CHX-loaded ICMs resulted in the transradicular diffusion of active components outside the tooth through the apex and the lateral dentinal tubules, as shown by the release of CHX (from 3.99 µg/mL to 51.28 µg/mL) and changes in pH (from 6.63 to 8.18) and calcium concentrations (from 2.42 ppm to 14.67 ppm) after 7 days. The 0.5% CHX-loaded ICM was non-toxic and reduced the release of IL-6 by periodontal cells stimulated by P. gingivalis lipopolysaccharides. Results indicate that the root canal may serve as a reservoir for periodontal drug delivery and that CHX-based ICMs can be an adjuvant for the control of infections and inflammation in endo-periodontal lesions.

Evaluation of Anti-inflammatory and Antimicrobial Properties of Mustard Seed Extract-Based Hydrogel: An In Vitro Study

INTRODUCTION

Mustard has been regarded as one of the world's most extensively produced and useful plants as well as one of the oldest condiments ever. The aim of the study was to develop and analyse the anti-inflammatory and antimicrobial properties of mustard seed extract.

METHODS

The extract was prepared by using a double filtration technique and anti-inflammatory properties were checked using egg albumin assay and bovine serum albumin assay and diclofenac sodium was the control. The antimicrobial property was evaluated by the Kirby-Bauer test and chlorhexidine gel was the control. The species included were Staphylococcus aureus, Streptococcus mutans, Enterococcus faecalis and Candida albicans.

RESULTS

The results showed that the anti-inflammatory property of mustard seed extract is comparable to diclofenac sodium whereas the maximum zone of inhibition was seen against C. albicans.

CONCLUSION

 This study discovered that mustard seed extract has potent antimicrobial and anti-inflammatory activity against a variety of oral microorganisms. These findings indicate that this hydrogel was highly active against the tested pathogens and will be effective in the treatment of periodontitis.

Preparation and Evaluation of Antimicrobial Properties and Cytotoxic Potentials of Nutmeg and Tulsi Gel

AIM

The aim of the study is to prepare the dual gel using nutmeg and Tulsi and then the evaluation of the antimicrobial properties and cytotoxic potential.

MATERIALS AND METHODS

The Nutmeg Tulsi gel preparation has been done with a mixture of equal amounts of nutmeg and Tulsi powder. To the above-mentioned mixture, 5 mL of the concentrate is added and mixed thoroughly until the gel formation is done. The antimicrobial property is checked in the Porphyromonas gingivalis organism (p>0.05). The cytotoxic potential is checked in the Brine variety of the shrimp. The statistical analysis is done using a Paired t-test.

RESULTS

The results stated that the Nutmeg Tulsi gel at a concentration of 100 microgram/mL showed a greater zone of inhibition (4.1±0.09 mm) when compared with doxycycline and has high antimicrobial potential in both Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Conclusion: The antimicrobial property of Nutmeg Tulsi gel has been demonstrated to be effective against P. gingivalis and A. actinomycetemcomitans. This suggests that it could be used as an affordable and effective "adjunct" alongside standard care for managing periodontal conditions.

Effect of continuous local dexamethasone on tissue biomechanics and histology after inhalational burn in a preclinical model

Objective

Inhalational burns frequently lead to dysphonia and airway stenosis. We hypothesize local dexamethasone delivery via a novel drug-eluting electrospun polymer-mesh endotracheal tube (ETT) reduces biomechanical and histologic changes in the vocal folds in inhalational burn.

Methods

Dexamethasone-loaded polymer mesh was electrospun onto ETTs trimmed to transglottic endolaryngeal segments and secured in nine Yorkshire Crossbreed swine with directed 150°C inhalation burns. Uncoated ETTs were implanted in nine additional swine with identical burns. ETT segments were maintained for 3 and 7 days. Vocal fold (VF) structural stiffness was measured using automated-indentation mapping and compared across groups and to four uninjured controls, and matched histologic assessment performed. Statistical analysis was conducted using two-way ANOVA with Tukey's post hoc test and Wilcoxon rank-sum test.

Results

VF stiffness after burn decreased with longer intubation, from 19.4 (7.6) mN/mm at 3 days to 11.3 (5.2) mN/mm at 7 days (p < .0001). Stiffness similarly decreased with local dexamethasone, from 25.9 (17.2) mN/mm at 3 days to 18.1 (13.0) mN/mm at 7 days (p < .0001). VF stiffness in the dexamethasone group was increased compared to tissues without local dexamethasone (p = .0002), and all groups with ETT placement had higher tissue stiffness at 3 days (p < .001). No significant change in histologic evidence of epithelial ulceration or fibrosis was noted, while an increased degree of inflammation was noted in the dexamethasone group (p = .04).

Conclusion

Local dexamethasone delivery increases VF stiffness and degree of inflammation compared to uncoated ETTs in an acute laryngeal burn model, reflected in early biomechanical and histologic changes in an inhalational burn model.

Clinical Effects of Subgingivally Delivered Achyranthes Aspera Gel in Chronic Periodontitis: A Clinical and Microbiological Study

Introduction

Periodontitis is an inflammatory disease of microbial origin. Local drug delivery agents help reduce subgingival microflora. Achyranthes aspera is a medicinal herb with antimicrobial, antioxidant, anti-inflammatory, and wound-healing properties.

Materials and Methods

A split-mouth study was conducted, in which 60 sites were included. Clinical parameters included measurements of probing depth (PD), gingival index, and clinical attachment level (CAL). Gingival crevicular fluid (GCF) samples were collected, followed by microbiological analysis of Porphyromonas Gingivalis. Clinical and microbiological parameters were recorded at baseline and after 3 months. Statistical analysis was done using the Statistical Package of Social Science (SPSS Version 22; Chicago Inc., USA).

Result

At 3 months, Group A resulted in greater mean reductions in clinical parameters: PD (3.77) as compared to Group B (5.23), and also greater mean CAL gain (3.18) in group A as compared to Group B (5.16). Group A also showed a significant reduction in the number of sites harboring periodontopathogens as compared to Group B.

Conclusion

A. aspera gel can be used as a nonsurgical local drug delivery agent in patients with chronic periodontitis as an effective adjunct to SRP.

A Hierarchical Structured Fiber Device Remodeling the Acidic Tumor Microenvironment for Enhanced Cancer Immunotherapy

The acidic microenvironment of tumors significantly reduces the anti-tumor effect of immunotherapy. Herein, a hierarchically structured fiber device is developed as a local drug delivery system for remodeling the acidic tumor microenvironment (TME) to improve the therapeutic effect of immunotherapy. Proton pump inhibitors in the fiber matrix can be sustainedly released to inhibit the efflux of intracellular H⁺ from tumor cells, resulting in the remodeling of the acidic TME. The targeted micelles and M1 macrophage membrane-coated nanoparticles in internal cavities of fiber can induce immunogenic cell death (ICD) of tumor cells and phenotypic transformation of tumor-associated macrophages (TAMs), respectively. The relief of the acidity in the TME further promotes ICD and the polarization of TAMs, alleviating the immunosuppressive microenvironment and synergistically enhancing the antitumor immune response. In vivo results reveal this local drug delivery system restores the pH value of TME from 6.8 to 7.2 and exhibit an excellent immunotherapeutic effect.

Sinonasal Stent Coated with Sustained-Release Varnish of Mometasone Furoate Inhibits Pro-Inflammatory Cytokine Release from Macrophages: An In Vitro Study

The aim of the study was to develop a sustained-release varnish (SRV) containing mometasone furoate (MMF) for sinonasal stents (SNS) to reduce mucosa inflammation in the sinonasal cavity. The SNS' segments coated with SRV-MMF or an SRV-placebo were incubated daily in a fresh DMEM at 37 °C for 20 days. The immunosuppressive activity of the collected DMEM supernatants was tested on the ability of mouse RAW 264.7 macrophages to secrete the cytokines' tumor necrosis factor α (TNFα) and interleukin (IL)-10 and IL-6 in response to lipopolysaccharide (LPS). The cytokine levels were determined by respective Enzyme-Linked Immunosorbent Assays (ELISAs). We found that the daily amount of MMF released from the coated SNS was sufficient to significantly inhibit LPS-induced IL-6 and IL-10 secretion from the macrophages up to days 14 and 17, respectively. SRV-MMF had, however, only a mild inhibitory effect on LPS-induced TNFα secretion as compared to the SRV-placebo-coated SNS. In conclusion, the coating of SNS with SRV-MMF provides a sustained delivery of MMF for at least 2 weeks, maintaining a level sufficient for inhibiting pro-inflammatory cytokine release. This technological platform is, therefore, expected to provide anti-inflammatory benefits during the postoperative healing period and may play a significant role in the future treatment of chronic rhinosinusitis.

Peregrine system infusion catheter for neurolytic renal denervation in hypertension: an overview of its safety and efficacy

INTRODUCTION

Resistant hypertension (HTN), despite the tremendous advances in pharmacotherapy, is a major global problem. Transcatheter renal denervation (RDN) could be a pertinent strategy for resistant HTN and patients with poor pharmacotherapy adherence. Nonetheless, the adoption of energy-based RDN in clinical practice is slow and alternative approaches are needed.

AREAS COVERED

The review focuses on the assessment of the Peregrine System Infusion Catheters. The system is designed for chemically mediated transcatheter RDN by the infusion publications on the Peregrine system. The theoretical assumptions for chemically mediated RDN, design of the system, data from preclinical and clinical studies, and further perspectives are discussed.

EXPERT OPINION

Peregrine System Infusion Catheters are the only catheter on the market designed for chemically mediated RDN by the infusion of the neurolytic agent. Chemical neurolysis more efficiently destroys nerves around the renal artery in comparison to energy-based catheters, due to deeper tissue penetration and circumferential distribution resulting in a wider range of effective nerve injury. Chemically mediated RDN by the infusion of the neurolytic agent (alcohol) has an excellent safety profile as confirmed in initial clinical trials which also suggested high efficacy. Currently, there is an ongoing phase III sham-control study. Other possible applications of this technology include clinical settings like heart failure or atrial fibrillation.

Perspectives on optimizing local delivery of drugs to peripheral nerves using mathematical models

Drug therapies for treating peripheral nerve injury repair have shown significant promise in preclinical studies. Despite this, drug treatments are not used routinely clinically to treat patients with peripheral nerve injuries. Drugs delivered systemically are often associated with adverse effects to other tissues and organs; it remains challenging to predict the effective concentration needed at an injured nerve and the appropriate delivery strategy. Local drug delivery approaches are being developed to mitigate this, for example via injections or biomaterial-mediated release. We propose the integration of mathematical modeling into the development of local drug delivery protocols for peripheral nerve injury repair. Mathematical models have the potential to inform understanding of the different transport mechanisms at play, as well as quantitative predictions around the efficacy of individual local delivery protocols. We discuss existing approaches in the literature, including drawing from other research fields, and present a process for taking forward an integrated mathematical-experimental approach to accelerate local drug delivery approaches for peripheral nerve injury repair. This article is categorized under: Neurological Diseases > Molecular and Cellular Physiology Neurological Diseases > Computational Models Neurological Diseases > Biomedical Engineering.

Antimicrobial and anti-inflammatory activity of Terminalia arjuna

Terminalia arjuna is one of the important herbal plants with cardioprotective, antihyperlipidemic activity and many more applications. In the present investigation, In order to find out the protective role, we prepared aqueous and ethanolic extract of Terminalia arjuna. The objective of this study was to comparatively evaluate the antimicrobial and anti-inflammatory activity of aqueous and ethanolic extract of Terminalia arjuna and to compare between the two. Antimicrobial activity of the plant extract was assessed by using agar well diffusion method against oral pathogens. The anti-inflammatory activity of prepared Terminalia arjuna plant extract was analyzed using egg albumin denaturation assay. The results of this study, showed that both aqueous and ethanolic extract had very good antimicrobial activity against Staphylococcus aureus, Pseudomonas species followed by Escherichia coli. However, the aqueous extract showed higher anti-inflammatory activity when compared with ethanolic extract. So it can be concluded that aqueous extract of Terminalia arjuna could be used as a local drug delivery agent in the treatment of chronic periodontitis.

Recent progress of hydrogel-based local drug delivery systems for postoperative radiotherapy

Surgical resection and postoperative radiotherapy remained the most common therapeutic modalities for malignant tumors. However, tumor recurrence after receiving such combination is difficult to be avoided because of high invasiveness and radiation resistance of cancer cells during long-term therapy. Hydrogels, as novel local drug delivery systems, presented excellent biocompatibility, high drug loading capacity and sustained drug release property. Compared with conventional drug formulations, hydrogels are able to be administered intraoperatively and directly release the entrapped therapeutic agents to the unresectable tumor sites. Therefore, hydrogel-based local drug delivery systems have their unique advantages especially in sensitizing postoperative radiotherapy. In this context, classification and biological properties of hydrogels were firstly introduced. Then, recent progress and application of hydrogels for postoperative radiotherapy were summarized. Finally, the prospects and challenges of hydrogels in postoperative radiotherapy were discussed.

A Placebo-Controlled Trial to Evaluate Two Locally Delivered Antibiotic Gels (Piperacillin Plus Tazobactam vs. Doxycycline) in Stage III-IV Periodontitis Patients

Background and objectives: this study aims to evaluate the clinical and microbiological effects of a single subgingival administration of a locally delivered antibiotic gel containing piperacillin plus tazobactam and compare it with a slow-release doxycycline (14%) gel and a placebo gel, following subgingival instrumentation (SI) in patients with severe periodontitis. Materials and methods: sixty-four patients diagnosed with stage III-IV periodontitis were enrolled, were randomly assigned into three groups, and were treated additionally with a single subgingival administration of piperacillin plus tazobactam gel (group A); doxycycline gel (group B); and placebo gel (group C). The primary outcome variable was the change in mean probing pocket depth (PPD) 6 months after the intervention. Secondary outcome variables were changes in mean full-mouth bleeding score (FMBS); full-mouth plaque score (FMPS); overall bleeding index (BOP); pocket closure; and clinical attachment level (CAL), along with changes in the numbers of five keystone bacteria: Aggregatibacter actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), Prevotella intermedia (P.i.), Tannerella forsythia (T.f.), and Treponema denticola (T.d.). Intergroup and intragroup differences were evaluated at 3 and 6 months. Results: at baseline, the three groups were comparable. An improvement in clinical parameters such as PPD, CAL, and BOP between groups was observed at 3 and 6 months, but without statistical significance (p > 0.05). At 6 months, the intragroup analysis showed a significant reduction in clinical parameters. Even though the piperacillin plus tazobactam group showed slightly higher PPD reduction, this was not statistically significant when compared to both control groups. Conclusions: The groups had similar results, and subgingival instrumentation can be executed without adjunctive antimicrobials, reducing the costs for the patient and the working time/load of the professional.

Controlled released naringin-loaded liposome/sucrose acetate isobutyrate hybrid depot for osteogenesis in vitro and in vivo

Introduction: A common problem in bone tissue engineering is that the burst release of active osteogenic factors is not beneficial for osteogenesis. This study aimed to prepare naringin (Ng) liposomes to reduce the burst release of Ng and improve new bone formation. Methods: We synthesized Ng liposomes using the thin-film hydration method. Drug-encapsulation efficacy experiments were conducted using the ultracentrifugation technique. The morphology and size distributions of freezedried liposomes were determined by transmission electron microscopy and dynamic light scattering. The Ng liposomes and Ng-lipo/sucrose acetate isobutyrate (SAIB) depots were characterized using Fourier transform infrared spectroscopy and in vitro release studies. After implantation of the Ng-lipo/SAIB depots, in vitro osteoblast-liposome interactions and in vivo osteogenesis were tested. Results: The formulation of freeze-dried Ng liposomes via an optimized recipe yielded nanosized (136.9 nm) negatively charged particles with a high encapsulation efficiency (~76.3%). Their chemical structure did not change after adding SAIB to the Ng liposomes. The burst release was reduced dramatically from 74.4% to 23.7%. In vivo, after 8 weeks, the new bone formation rate in the calvarial defects of Sprague-Dawley rats receiving Ng-lipo/SAIB was 57% compared with 25.18% in the control group (p = .0003). Discussion: Our results suggested that Ng-lipo/SAIB hybrid depots could serve as candidate materials for drug delivery in bone regeneration applications.

In vitro testing and efficacy of poly-lactic acid coating incorporating antibiotic loaded coralline bioceramic on Ti6Al4V implant against Staphylococcus aureus

Biofilm formation on an implant surface is most commonly caused by the human pathogenic bacteria Staphylococcus aureus, which can lead to implant related infections and failure. It is a major problem for both implantable orthopedic and maxillofacial devices. The current antibiotic treatments are typically delivered orally or in an injectable form. They are not highly effective in preventing or removing biofilms, and they increase the risk of antibiotic resistance of bacteria and have a dose-dependent negative biological effect on human cells. Our aim was to improve current treatments via a localized and controlled antibiotic delivery-based implant coating system to deliver the antibiotic, gentamicin (Gm). The coating contains coral skeleton derived hydroxyapatite powders (HAp) that act as antibiotic carrier particles and have a biodegradable poly-lactic acid (PLA) thin film matrix. The system is designed to prevent implant related infections while avoiding the deleterious effects of high concentration antibiotics in implants on local cells including primary human adipose derived stem cells (ADSCs). Testing undertaken in this study measured the rate of S. aureus biofilm formation and determined the growth rate and proliferation of ADSCs. After 24 h, S. aureus biofilm formation and the percentage of live cells found on the surfaces of all 5%-30% (w/w) PLA-Gm-(HAp-Gm) coated Ti6Al4V implants was lower than the control samples. Furthermore, Ti6Al4V implants coated with up to 10% (w/w) PLA-Gm-(HAp-Gm) did not have noticeable Gm related adverse effect on ADSCs, as assessed by morphological and surface attachment analyses. These results support the use and application of the antibacterial PLA-Gm-(HAp-Gm) thin film coating design for implants, as an antibiotic release control mechanism to prevent implant-related infections.

Achievements in Mesoporous Bioactive Glasses for Biomedical Applications

Nowadays, mesoporous bioactive glasses (MBGs) are envisaged as promising candidates in the field of bioceramics for bone tissue regeneration. This is ascribed to their singular chemical composition, structural and textural properties and easy-to-functionalize surface, giving rise to accelerated bioactive responses and capacity for local drug delivery. Since their discovery at the beginning of the 21st century, pioneering research efforts focused on the design and fabrication of MBGs with optimal compositional, textural and structural properties to elicit superior bioactive behavior. The current trends conceive MBGs as multitherapy systems for the treatment of bone-related pathologies, emphasizing the need of fine-tuning surface functionalization. Herein, we focus on the recent developments in MBGs for biomedical applications. First, the role of MBGs in the design and fabrication of three-dimensional scaffolds that fulfil the highly demanding requirements for bone tissue engineering is outlined. The different approaches for developing multifunctional MBGs are overviewed, including the incorporation of therapeutic ions in the glass composition and the surface functionalization with zwitterionic moieties to prevent bacterial adhesion. The bourgeoning scientific literature on MBGs as local delivery systems of diverse therapeutic cargoes (osteogenic/antiosteoporotic, angiogenic, antibacterial, anti-inflammatory and antitumor agents) is addressed. Finally, the current challenges and future directions for the clinical translation of MBGs are discussed.

Microfluidic Preparation of Gelatin Methacryloyl Microgels as Local Drug Delivery Vehicles for Hearing Loss Therapy

Local drug delivery has become an effective method for disease therapy in fine organs including ears, eyes, and noses. However, the multiple anatomical and physiological barriers, unique clearance pathways, and sensitive perceptions characterizing these organs have led to suboptimal drug delivery efficiency. Here, we developed dexamethasone sodium phosphate-encapsulated gelatin methacryloyl (Dexsp@GelMA) microgel particles, with finely tunable size through well-designed microfluidics, as otic drug delivery vehicles for hearing loss therapy. The release kinetics, encapsulation efficiency, drug loading efficiency, and cytotoxicity of the GelMA microgels with different degrees of methacryloyl substitution were comprehensively studied to optimize the microgel formulation. Compared to bulk hydrogels, Dexsp@GelMA microgels of certain sizes hardly cause air-conducted hearing loss in vivo. Besides, strong adhesion of the microgels on the round window membrane was demonstrated. Moreover, the Dexsp@GelMA microgels, via intratympanic administration, could ameliorate acoustic noise-induced hearing loss and attenuate hair cell loss and synaptic ribbons damage more effectively than Dexsp alone. Our results strongly support the adhesive and intricate microfluidic-derived GelMA microgels as ideal intratympanic delivery vehicles for inner ear disease therapies, which provides new inspiration for microfluidics in drug delivery to the fine organs.

Intraductal delivery of nanocarriers for ductal carcinoma in situ treatment: a strategy to enhance localized delivery

Ductal carcinoma in situ describes the most commonly occurring, noninvasive malignant breast disease, which could be the leading factor in invasive breast cancer. Despite remarkable advancements in treatment options, poor specificity, low bioavailability and dose-induced toxicity of chemotherapy are the main constraint. A unique characteristic of nanocarriers may overcome these problems. Moreover, the intraductal route of administration serves as an alternative approach. The direct nanodrug delivery into mammary ducts results in the accumulation of anticancer agents at targeted tissue for a prolonged period with high permeability, significantly decreasing the tumor size and improving the survival rate. This review focuses mainly on the intraductal delivery of nanocarriers in treating ductal carcinoma in situ, together with potential clinical translational research.

Prospection of Microfluidics for Local Drug Delivery

Significant endeavors can be made to develop effective drug delivery systems. Nowadays, many of these novel systems have gained attention as they focus primarily on increasing the bioavailability and bioaccessibility of several drugs to finally minimize the side effects, thus improving the treatment's efficacy. Microfluidics systems are unquestionably a superior technology, which is currently revolutionizing the current chemical and biological studies, providing diminutive chip-scale devices that offer precise dosage, target-precise delivery, and controlled release. Microfluidic systems have emerged as a promising delivery vehicle owing to their potential for defined handling and transporting of small liquid quantities. The latest microfabrication developments have been made for application to several biological systems. Here, we review the fundamentals of microfluidics and their application for local drug delivery.

Off-the-Shelf, Heparinized Small Diameter Vascular Graft Limits Acute Thrombogenicity in a Porcine Model

Thrombogenicity poses a challenge to the clinical translation of engineered grafts. Previously, small-diameter vascular grafts (sdVG) composed of fibrin hydrogel microfiber tubes (FMT) with an external poly(ε-caprolactone) (PCL) sheath supported long-term patency in mice. Towards the development of an sdVG with off-the-shelf availability, the FMT's shelf stability, scale-up, and successful conjugation of an antithrombotic drug to the fibrin scaffold are reported here. FMTs maintain mechanical stability and high-water retention after storage for one year in a freezer, in a refrigerator, or at room temperature. Low molecular weight heparin-conjugated fibrin scaffolds enabled local and sustained delivery during two weeks of enzymatic degradation. Upscaled fabrication of sdVGs provides natural biodegradable grafts with size and mechanics suitable for human application. Implantation in a carotid artery interposition porcine model exhibited no rupture with thrombi prevented in all heparinized sdVGs (n=4) over 4-5 weeks. Remodeling of the sdVGs is demonstrated with endothelial cells on the luminal surface and initial formation of the medial layer by 4-5 weeks. However, neointimal hyperplasia at 4-5 weeks led to the stenosis and occlusion of most of the sdVGs, which must be resolved for future long-term in vivo assessments. The off-the-shelf, biodegradable heparinized fibrin sdVG layer limits acute thrombogenicity while mediating extensive neotissue formation as the PCL sheath maintains structural integrity. STATEMENT OF SIGNIFICANCE: : To achieve clinical and commercial utility of small-diameter vascular grafts as arterial conduits, these devices must have off-the-shelf availability for emergency arterial bypass applications and be scaled to a size suitable for human applications. A serious impediment to clinical translation is thrombogenicity. Treatments have focused on long-term systemic drug therapy, which increases the patient's risk of bleeding complications, or coating grafts and stents with anti-coagulants, which minimally improves patient outcomes even when combined with dual anti-platelet therapy. We systematically modified the biomaterial properties to develop anticoagulant embedded, biodegradable grafts that maintain off-the-shelf availability, provide mechanical stability, and prevent clot formation through local drug delivery.

Comparative Evaluation of Locally Administered 2% Gel Fabricated from Lemongrass Polymer and 10% Doxycycline Hyclate Gel as an Adjunct to Scaling and Root Planing in the Treatment of Chronic Periodontitis-A Randomized Controlled Trial

Background: Extracts of medicinal plant like lemongrass offer a new choice for optional antimicrobial therapy against various oral microorganisms. The objective of this study was to assess, verify, and compare the antimicrobial effectiveness of locally administered 2% lemongrass gel and 10% doxycycline hyclate gel as an adjunct to scaling and root planing (SRP) in treating chronic periodontitis. Method: This is a double-blind parallel arm randomized controlled study. Forty subjects were randomly divided into Group A and B for 2% lemongrass gel and 10% doxycycline hyclate gel, respectively. The clinical assessments of Gingival Index (GI), Plaque Index (PI), Probing Pocket Depth (PPD), and Clinical Attachment Level (CAL) together with microbial colony counts for Porphyromonas gingivalis, Actinomyces naeslundii, and Prevotella intermedia were done at baseline, 1st month, and 3rd month follow-ups. Results: The results showed there was a significant reduction in the mean scores of GI, PPD, and CAL clinical indices from baseline to the 1st and 3rd month follow-ups in both the 2% lemongrass gel and 10% doxycycline gel groups (p < 0.05). Similarly, there was significant reduction in mean CFU scores for all periodontal pathogens from baseline to 1st and 3rd month follow-ups in both the 2% lemongrass gel and 10% doxycycline gel groups (p < 0.05). Conclusions: It could be concluded that the local delivery of 2% lemongrass gel as an adjunct to scaling and root planing is effective and comparable to 10% doxycycline gel in the treatment of chronic periodontitis.

A new era of Nano!!! Comparative evaluation of ganglioside polymeric nanoparticle coated satranidazole gel and 1% metronidazole gel for the treatment of periodontitis

Background:

The present study was intended to comparatively assess the efficacy of ganglioside polymeric nanoparticle-coated 0.25% satranidazole-loaded nanoparticles in gel form with that of the commercially available 1% metronidazole gel as a local drug delivery (LDD) agent for the treatment of periodontal pockets.

Materials and Methods:

A split-mouth randomized clinical trial was carried out in 46 chronic periodontitis patients with probing pocket depth (PPD) ≥4 mm or clinical attachment loss greater than 3 mm on both quadrants of the same arch. Full-mouth scaling and root planing (SRP) was performed for all the patients followed by application of 0.25% satranidazole-loaded nanoparticles in gel form on one site (Group 1) and commercially available 1% metronidazole gel on another site (Group 2). Clinical parameters (gingival index, plaque index, PPD, clinical attachment level gain, and bleeding on probing) and microbiological analysis of the subgingival plaque samples were performed and assessed at baseline, after SRP, 21^st day, and 90^th day post treatment. Unpaired “t”-test and ANOVA tests were used for intergroup and intragroup comparison of recorded parameters.

Results:

The results showed that the satranidazole-loaded nanoparticle group as an adjunct to SRP in chronic periodontitis showed a statistically significant improvement in all the clinical parameters and a fewer relapse of microbial flora in comparison with the metronidazole group as an LDD agent.

Conclusion:

The present study depicted that both the LDD agents showed an effective improvement of clinical as well as microbiological parameters, but the satranidazole group consistently produced better results than the metronidazole group and hence has a promising future as an LDD agent in treating periodontal pockets.

In Situ Micro-Nano Conversion Augmented Tumor-Localized Immunochemotherapy

The immune checkpoint blockade (ICB) therapy based on monoclonal antibodies still suffers from a lower immune response rate and severe immune-related side effects, which greatly compromise its therapeutic benefits. Herein, ultrasound (US) microbubbles (MBs) that locally delivered the camptothecin-floxuridine (CF) drug combination and anti-PD-L1 blocking antibody (αPD-L1) to tumors were developed to improve ICB therapy. The resulting αPCF MBs exhibited good stability, allowing their use as US imaging contrast agents to trace the drug delivery in vivo. Furthermore, the combination of αPCF MBs treatment and disrupted US irradiation triggered tumor in situ conversion of αPCF MBs to αPCF NPs while promoting higher tumor cell uptake and deeper tumor penetration as confirmed by the US/fluorescence bimodal imaging. Camptothecin (CPT) and floxuridine (FUDR) were further released at a fixed 1:1 molar ratio within the tumor microenvironment (TME) to synergistically elicit an immunogenic tumor phenotype and sensitize tumors to αPD-L1-mediated ICB therapy, while the local simultaneous delivery of immunotherapeutic αPD-L1 further reversed the immunosuppressive tumor microenvironment and promoted the infiltration of cytotoxic T lymphocytes (CTLs), thus achieving a synergistic therapeutic effect of chemotherapy and immunotherapy in the CT26 tumor-bearing mice. Thus, αPCF MBs + US mediated local co-delivering of the drug combination and αPD-L1 well augmented the ICB therapy while effectively minimizing the off-target side effects, providing a safe and universal therapeutic strategy for tumor immunotherapy.

One-Year Clinical, Microbiological and Immunological Results of Local Doxycycline or Antimicrobial Photodynamic Therapy for Recurrent/Persisting Periodontal Pockets: A Randomized Clinical Trial

We evaluated, in this study, the clinical, microbiological and immunological effects of local drug delivery (LDD) or photodynamic therapy (PDT), adjunctive to subgingival instrumentation (SI) in persistent or recurrent periodontal pockets in patients enrolled in supportive periodontal therapy (SPT) after one year. A total of 105 patients enrolled in SPT with persistent/recurrent pockets were randomly treated with SI +PDT or SI + LDD or SI (control). The number of treated sites with bleeding on probing (n BOP+), probing pocket depths (PPD), clinical attachment level (CAL), full-mouth plaque and bleeding scores (gingival bleeding index, %bleeding on probing-BOP) was evaluated at baseline and after 12 months. Additionally, eight periodontopathogens and the immunomarkers IL-1β (interleukin)and MMP-8 (matrix metalloprotease) were quantitatively determined using real-time PCR and ELISA, respectively. All three treatments resulted in statistically significant clinical improvements (p < 0.05) without statistically significant intergroup differences (p > 0.05), which were maintained up to 12 months. The presence of BOP negatively affected the PPD and CAL. Moreover, statistically significantly fewer bleeding sites at 12 months were observed in the test groups (p = 0.049). Several periodontopathogens were reduced after 12 months. In conclusion, the present data indicate that in periodontal patients enrolled in SPT, treatment of persistent/recurrent pockets with SI alone or combined with either PDT or LDD may lead to comparable clinical, microbiological and immunological improvements, which are maintained up to 12 months. Secondly, the presence of BOP directly impacts the PPD and CAL.

Evaluation of efficacy of subgingival administration of 1% chlorhexidine gel as an adjunct to scaling and root planing in the treatment of chronic periodontitis - A clinical and microbiological study

AIM

The aim of the present study was to evaluate the clinical and microbiological effects of subgingival administration of 1% chlorhexidine gel (Chlorhexamed® 1% gel) in patients with chronic periodontitis.

SETTINGS AND DESIGN

The study was done in a parallel-arm design with a total of 30 patients with 60 sites suffering from chronic periodontitis. The patients were divided into control and experimental groups.

MATERIALS AND METHODS

The clinical parameters recorded were plaque index, gingival index, modified sulcular bleeding index, probing pocket depth and relative attachment level at baseline, 1 month and 3 month. Microbiological colony-forming units were assessed for Porphyromonas gingivalis, Fusobacterium nucleatum and Tannerella forsythia at baseline, 1 week, 1 month and 3 months. The control group received scaling and root planing (SRP) after baseline evaluation; however, the experimental group received the application of Chlorhexamed® gel within 48 hours after SRP. Then, the values obtained were subjected to statistical analysis.

RESULTS

Both groups showed significant improvement from the baseline to 3 months in all clinical and microbiological parameters. The experimental group showed better improvement in all parameters.

CONCLUSION

The use of Chlorhexamed® gel has proven to be an efficacious adjunct with SRP in the treatment of chronic periodontitis.

Engineered Delivery of Dental Stem-Cell-Derived Extracellular Vesicles for Periodontal Tissue Regeneration

Periodontal disease begins as an inflammatory response to a bacterial biofilm deposited around the teeth, which over time leads to the destruction of tooth-supporting structures and consequently tooth loss. Conventional treatment strategies show limited efficacy in promoting regeneration of damaged periodontal tissues. Here, a delivery platform is developed for small extracellular vesicles (sEVs) derived from gingival mesenchymal stem cells (GMSCs) to treat periodontitis. EVs can achieve comparable therapeutic effects to their cells of origin. However, the short half-lives of EVs after their administration along with their rapid diffusion away from the delivery site necessitate frequent administration to achieve therapeutic benefits. To address these issues, "dual delivery" microparticles are engineered enabling microenvironment-sensitive release of EVs by metalloproteinases at the affected site along with antibiotics to suppress bacterial biofilm growth. GMSC sEVs are able to decrease the secretion of pro-inflammatory cytokines by monocytes/macrophages and T cells, suppress T-cell activation, and induce the formation of T regulatory cells (Tregs) in vitro and in a rat model of periodontal disease. One-time administration of immunomodulatory GMSC sEV-decorated microparticles leads to a significant improvement in regeneration of the damaged periodontal tissue. This approach will have potential clinical applications in the regeneration of a variety of tissues.

Bioadhesive Nanoparticles for Local Drug Delivery

Local drug delivery is an effective strategy for achieving direct and instant therapeutic effects. Current clinical treatments have fallen short and are limited by traditional technologies. Bioadhesive nanoparticles (NPs), however, may be a promising carrier for optimized local drug delivery, offering prolonged drug retention time and steadily maintained therapeutic concentrations. In addition, the possibility of clinical applications of this platform are abundant, as most polymers used for bioadhesion are both biodegradable and biocompatible. This review highlights the major advances in the investigations of polymer-based bioadhesive nanoparticles and their innumerable applications in local drug delivery.

Tobramycin Supplemented Small-Diameter Vascular Grafts for Local Antibiotic Delivery: A Preliminary Formulation Study

Peripheral artery occlusive disease is an emerging cardiovascular disease characterized by the blockage of blood vessels in the limbs and is associated with dysfunction, gangrene, amputation, and a high mortality risk. Possible treatments involve by-pass surgery using autologous vessel grafts, because of the lack of suitable synthetic small-diameter vascular prosthesis. One to five percent of patients experience vascular graft infection, with a high risk of haemorrhage, spreading of the infection, amputation and even death. In this work, an infection-proof vascular graft prototype was designed and manufactured by electrospinning 12.5% w/v poly-L-lactic-co-glycolic acid solution in 75% v/v dichloromethane, 23.8% v/v dimethylformamide and 1.2% v/v water, loaded with 0.2% w/w_PLGA. Polymer and tobramycin concentrations were selected after viscosity and surface tension and after HPLC-UV encapsulation efficiency (EE%) evaluation, respectively. The final drug-loaded prototype had an EE% of 95.58% ± 3.14%, with smooth fibres in the nanometer range and good porosity; graft wall thickness was 291 ± 20.82 μm and its internal diameter was 2.61 ± 0.05 mm. The graft's antimicrobic activity evaluation through time-kill assays demonstrated a significant and strong antibacterial activity over 5 days against Staphylococcus aureus and Escherichia coli. An indirect cell viability assay on Normal Human Dermal Fibroblasts (NHDF) confirmed the cytocompatibility of the grafts.

Antioxidant Enzymes Sequestered within Lipid-Polymer Hybrid Nanoparticles for the Local Treatment of Inflammatory Bowel Disease

The local treatment of inflammatory bowel disease (IBD) by enzyme therapeutics is challenging owing to hostile environments in the gastrointestinal tract, leading to the hydrolysis and enzymatic degradation of labile proteins. In this study, safe and efficient local drug delivery systems were developed by antioxidant superoxide dismutase (SOD) sequestered within lipid-polymer hybrid nanoparticles through sequential self-assembly processes. Interestingly, we found that the sequestered SOD exhibited long-term enzymatic stability and comparable biological activity to the enzymes in the native form, probably owing to particle encapsulation providing a physical barrier to prevent the enzymolysis of proteins. We demonstrated that nanoparticle-based local drug delivery systems showed excellent mucus-penetrating ability and inflammation-targeting properties, owing to the particle surface with a poly(ethylene glycol) (PEG) coating and folate functionalization, thus improving mucosal retention time and drug delivery efficiency within the colorectal region. Furthermore, SOD-containing lipid-polymer hybrid nanoparticles could effectively mitigate inflammatory responses by regulating the secretion of inflammation-associated cytokines, thus increasing therapeutic outcomes in colitis mice through intrarectal administration. The findings indicated that antioxidant enzymes sequestered within lipid-polymer hybrid nanoparticles might be potential enzyme therapeutics for the local treatment of some inflammatory diseases in the near future.

Recent advances in the local antibiotics delivery systems for management of osteomyelitis

Chronic osteomyelitis is a challenging disease due to its serious rates of mortality and morbidity while the currently available treatment strategies are suboptimal. In contrast to the adopted systemic treatment approaches after surgical debridement in chronic osteomyelitis, local drug delivery systems are receiving great attention in the recent decades. Local drug delivery systems using special carriers have the pros of enhancing the feasibility of penetration of antimicrobial agents to bone tissues, providing sustained release and localized concentrations of the antimicrobial agents in the infected area while avoiding the systemic side effects and toxicity. Most important, the incorporation of osteoinductive and osteoconductive materials in these systems assists bones proliferation and differentiation, hence the generation of new bone materials is enhanced. Some of these systems can also provide mechanical support for the long bones during the healing process. Most important, if the local systems are designed to be injectable to the affected site and biodegradable, they will reduce the level of invasion required for implantation and can win the patients’ compliance and reduce the healing period. They will also allow multiple injections during the course of therapy to guard against the side effect of the long-term systemic therapy. The current review presents different available approaches for delivering antimicrobial agents for the treatment of osteomyelitis focusing on the recent advances in researches for local delivery of antibiotics.

HIGHLIGHTS

Chronic osteomyelitis is a challenging disease due to its serious mortality and morbidity rates and limited effective treatment options.

Local drug delivery systems are receiving great attention in the recent decades.

Osteoinductive and osteoconductive materials in the local systems assists bones proliferation and differentiation

Local systems can be designed to provide mechanical support for the long bones during the healing process.

Designing the local system to be injectable to the affected site and biodegradable will reduces the level of invasion and win the patients’ compliance.

A Two-Photon Microimaging-Microdevice System for Four-Dimensional Imaging of Local Drug Delivery in Tissues

Advances in the intratumor measurement of drug responses have included a pioneering biomedical microdevice for high throughput drug screening in vivo, which was further advanced by integrating a graded-index lens based two-dimensional fluorescence micro-endoscope to monitor tissue responses in situ across time. While the previous system provided a bulk measurement of both drug delivery and tissue response from a given region of the tumor, it was incapable of visualizing drug distribution and tissue responses in a three-dimensional (3D) way, thus missing the critical relationship between drug concentration and effect. Here we demonstrate a next-generation system that couples multiplexed intratumor drug release with continuous 3D spatial imaging of the tumor microenvironment via the integration of a miniaturized two-photon micro-endoscope. This enables optical sectioning within the live tissue microenvironment to effectively profile the entire tumor region adjacent to the microdevice across time. Using this novel microimaging-microdevice (MI-MD) system, we successfully demonstrated the four-dimensional imaging (3 spatial dimensions plus time) of local drug delivery in tissue phantom and tumors. Future studies include the use of the MI-MD system for monitoring of localized intra-tissue drug release and concurrent measurement of tissue responses in live organisms, with applications to study drug resistance due to nonuniform drug distribution in tumors, or immune cell responses to anti-cancer agents.

Systemic and Local Silk-Based Drug Delivery Systems for Cancer Therapy

For years, surgery, radiotherapy, and chemotherapy have been the gold standards to treat cancer, although continuing research has sought a more effective approach. While advances can be seen in the development of anticancer drugs, the tools that can improve their delivery remain a challenge. As anticancer drugs can affect the entire body, the control of their distribution is desirable to prevent systemic toxicity. The application of a suitable drug delivery platform may resolve this problem. Among other materials, silks offer many advantageous properties, including biodegradability, biocompatibility, and the possibility of obtaining a variety of morphological structures. These characteristics allow the exploration of silk for biomedical applications and as a platform for drug delivery. We have reviewed silk structures that can be used for local and systemic drug delivery for use in cancer therapy. After a short description of the most studied silks, we discuss the advantages of using silk for drug delivery. The tables summarize the descriptions of silk structures for the local and systemic transport of anticancer drugs. The most popular techniques for silk particle preparation are presented. Further prospects for using silk as a drug carrier are considered. The application of various silk biomaterials can improve cancer treatment by the controllable delivery of chemotherapeutics, immunotherapeutics, photosensitizers, hormones, nucleotherapeutics, targeted therapeutics (e.g., kinase inhibitors), and inorganic nanoparticles, among others.

Long-acting implantable corticosteroid matrix for chronic rhinosinusitis: Results of LANTERN Phase 2 randomized controlled study

Background

Topical steroids are first‐line treatment for chronic rhinosinusitis (CRS), but fail to provide adequate symptom control for all patients. Designed for medical treatment failures, LYR‐210 is an implantable matrix that locally elutes mometasone furoate to inflamed sinonasal tissue for up to 24 weeks in CRS patients. In an open‐label phase 1 study, LYR‐210 demonstrated clinically relevant improvement in the 22‐item Sino‐Nasal Outcome Test (SNOT‐22). Safety and efficacy of LYR‐210 in CRS were evaluated in the LANTERN Phase 2 study.

Methods

Sixty‐seven surgically naive adult CRS patients who were inadequately controlled by previous medical management and seeking an alternative treatment enrolled in a multicenter, blinded, controlled, dose‐ranging study. Patients had moderate‐to‐severe disease based on SNOT‐22 and composite 7‐day average scores of the 4 cardinal CRS symptoms (4CS), with diagnosis confirmed by nasal endoscopy and magnetic resonance imaging. Patients were randomized (1:1:1) to saline irrigation–only control or bilateral in‐office administration of LYR‐210 (2500 μg) or LYR‐210 (7500 μg). Safety and efficacy were evaluated over 24 weeks.

Results

Both LYR‐210 doses were safe and well‐tolerated over the 24‐week treatment period. LYR‐210 demonstrated rapid and durable dose‐dependent symptom improvement based on 4CS and SNOT‐22, with LYR‐210 (7500 μg) achieving statistical significance as early as 8 weeks and out to 24 weeks compared with control. LYR‐210 (7500 μg) reduced rescue treatment use and radiographic ethmoid opacification at week 24.

Conclusions

LYR‐210 is the first implantable sinonasal treatment to achieve up to 24 weeks of benefit from a single administration in surgically naive CRS patients with and without nasal polyps.

An Overview of Chitosan and Its Role in Periodontics

Chitosan is a biopolymer with numerous biological properties such as antibacterial, anti-inflammatory, and wound healing. Chitosan also stimulates cell proliferation and osteogenesis and thus used as a scaffold material in tissue engineering. The physical proprieties of chitosan such as biocompatibility and biodegradability give promising results in periodontal therapies. This review gives an updated explanation of the applications of chitosan in dentistry and periodontics. Furthermore, the review demonstrates the actions of chitosan in detail and its role in the regeneration of periodontal structures.

Mesenchymal stem cells and local tacrolimus delivery synergistically enhance neurite extension

BACKGROUND

The aim of this study was to investigate the combined effect of mesenchymal stem cells (MSC) and local delivery of tacrolimus (FK506) on nerve regeneration when applied to nerve autografts and decellularized allografts.

METHODS

A three-dimensional in vitro compartmented cell culture system consisting of a neonatal dorsal root ganglion adjacent to a nerve graft was used to evaluate the regenerating neurites into the peripheral nerve scaffold. Nerve autografts and allografts were treated with (i) undifferentiated MSCs, (ii) FK506 (100 ng/mL) or (iii) both (N = 9/group). After 48 hours, neurite extension was measured to quantify nerve regeneration and stem cell viability was evaluated.

RESULTS

Stem cell viability was confirmed in all MSC-treated grafts. Neurite extension was superior in autografts treated with FK506, and MSCs and FK506 combined (p < 0.001 and p = 0.0001, respectively), and autografts treated with MSCs (p = 0.12) were comparable to untreated autografts. In allografts, FK506 treatment and combined treatment were superior to controls (p < 0.001 and p = 0.0001, respectively), and treatment with MSCs (p = 0.09) was comparable to controls. All autograft groups were superior compared to their respective allograft treatment group (p < 0.05) in neurite extension.

CONCLUSIONS

Alone, either MSC or FK506 treatment improved neurite outgrowth, and combined they further enhanced neurite extension in both autografts and allografts.

Methods of Topical Administration of Drugs and Biological Active Substances for Dental Implants-A Narrative Review

Dental implants are, nowadays, established surgical devices for the restoration of lost teeth. Considered as an alternative for traditional prosthetic appliances, dental implants surpass them in reliability and patient feedback. Local drug delivery around the implants promotes osseointegration and reduces peri-implantitis. However, there are currently no methods of a multiple, precise topical administration of drugs to the implant area. Engineering coatings on the implants, drug application on carriers during implantation, or gingival pockets do not meet all requirements of dental surgeons. Therefore, there is a need to create porous implants and other medical devices that will allow a multiple drug delivery at a controlled dose and release profile without traumatic treatment. Due to the growing demand for the use of biologically active agents to support dental implant treatment at its various stages (implant placement, long-term use of dental superstructures, treatment of the peri-implant conditions) and due to the proven effectiveness of the topical application of pharmacological biologically active agents to the implant area, the authors would like to present a review and show the methods and devices that can be used by clinicians for local drug administration to facilitate dental implant treatment. Our review concludes that there is a need for research in the field of inventions such as new medical devices or implants with gradient solid-porous structures. These devices, in the future, will enable to perform repeatable, controllable, atraumatic, and repeatable injections of active factors that may affect the improvement of osteointegration and the longer survival of implants, as well as the treatment of peri-implantitis.

Anti-Inflammatory Effect of Very High Dose Local Vessel Wall Statin Administration: Poly(L,L-Lactide) Biodegradable Microspheres with Simvastatin for Drug Delivery System (DDS)

Atherosclerosis involves an ongoing inflammatory response of the vascular endothelium and vessel wall of the aorta and vein. The pleiotropic effects of statins have been well described in many in vitro and in vivo studies, but these effects are difficult to achieve in clinical practice due to the low bioavailability of statins and their first-pass metabolism in the liver. The aim of this study was to test a vessel wall local drug delivery system (DDS) using PLA microstructures loaded with simvastatin. Wistar rats were fed high cholesterol chow as a model. The rat vessels were chemically injured by repeated injections of perivascular paclitaxel and 5-fluorouracil. The vessels were then cultured and treated by the injection of several concentrations of poly(L,L-lactide) microparticles loaded with the high local HMG-CoA inhibitor simvastatin (0.58 mg/kg) concentration (SVPLA). Histopathological examinations of the harvested vessels and vital organs after 24 h, 7 days and 4 weeks were performed. Microcirculation in mice as an additional test was performed to demonstrate the safety of this approach. A single dose of SVPLA microspheres with an average diameter of 6.4 μm and a drug concentration equal to 8.1% of particles limited the inflammatory reaction of the endothelium and vessel wall and had no influence on microcirculation in vivo or in vitro. A potent pleiotropic (anti-inflammatory) effect of simvastatin after local SVPLA administration was observed. Moreover, significant concentrations of free simvastatin were observed in the vessel wall (compared to the maximum serum level). In addition, it appeared that simvastatin, once locally administered as SVPLA particles, exerted potent pleiotropic effects on chemically injured vessels and presented anti-inflammatory action. Presumably, this effect was due to the high local concentrations of simvastatin. No local or systemic side effects were observed. This approach could be useful for local simvastatin DDSs when high, local drug concentrations are difficult to obtain, or systemic side effects are present.

A Diels-Alder polymer platform for thermally enhanced drug release toward efficient local cancer chemotherapy

We reports a novel thermally enhanced drug release system synthesized via a dynamic Diels-Alder (DA) reaction to develop chemotherapy for pancreatic cancer. The anticancer prodrug was designed by tethering gemcitabine (GEM) to poly(furfuryl methacrylate) (PFMA) via N-(3-maleimidopropionyloxy)succinimide as a linker by DA reaction (PFMA-L-GEM). The conversion rate of the DA reaction was found to be approximately 60% at room temperature for 120 h. The reversible deconstruction of the DA covalent bond in retro Diels-Alder (rDA) reaction was confirmed by proton nuclear magnetic resonance, and the reaction was significantly accelerated at 90 °C. A PFMA-LGEM film containing magnetic nanoparticles (MNPs) was prepared for thermally enhanced release of the drug via the rDA reaction. Drug release was initiated by heating MNPs by alternating magnetic field. This enables local heating within the film above the rDA reaction temperature while maintaining a constant surrounding medium temperature. The MNPs/PFMA-L-GEM film decreased the viability of pancreatic cancer cells by 49% over 24 h. Our results suggest that DA/rDA-based thermally enhanced drug release systems can serve as a local drug release platform and deliver the target drug within locally heated tissue, thereby improving the therapeutic efficiency and overcoming the side effects of conventional drugs used to treat pancreatic cancer.

Design and Testing of Efficient Mucus-Penetrating Nanogels-Pitfalls of Preclinical Testing and Lessons Learned

Mucosal surfaces pose a challenging environment for efficient drug delivery. Various delivery strategies such as nanoparticles have been employed so far; yet, still yielding limited success. To address the need of efficient transmucosal drug delivery, this report presents the synthesis of novel disulfide-containing dendritic polyglycerol (dPG)-based nanogels and their preclinical testing. A bifunctional disulfide-containing linker is coupled to dPG to act as a macromolecular crosslinker for poly-N-isopropylacrylamide (PNIPAM) and poly-N-isopropylmethacrylamide (PNIPMAM) in a precipitation polymerization process. A systematic analysis of the polymerization reveals the importance of a careful polymer choice to yield mucus-degradable nanogels with diameters between 100 and 200 nm, low polydispersity, and intact disulfide linkers. Absorption studies in porcine intestinal tissue and human bronchial epithelial models demonstrate that disulfide-containing nanogels are highly efficient in overcoming mucosal barriers. The nanogels efficiently degrade and deliver the anti-inflammatory biomacromolecule etanercept into epithelial tissues yielding local anti-inflammatory effects. Over the course of this work, several problems are encountered due to a limited availability of valid test systems for mucosal drug-delivery systems. Hence, this study also emphasizes how critical a combined and multifaceted approach is for the preclinical testing of mucosal drug-delivery systems, discusses potential pitfalls, and provides suggestions for solutions.

Immunosuppressive PLGA TGF-β1 Microparticles Induce Polyclonal and Antigen-Specific Regulatory T Cells for Local Immunomodulation of Allogeneic Islet Transplants

Allogeneic islet transplantation is a promising cell-based therapy for Type 1 Diabetes (T1D). The long-term efficacy of this approach, however, is impaired by allorejection. Current clinical practice relies on long-term systemic immunosuppression, leading to severe adverse events. To avoid these detrimental effects, poly(lactic-co-glycolic acid) (PLGA) microparticles (MPs) were engineered for the localized and controlled release of immunomodulatory TGF-β1. The in vitro co-incubation of TGF-β1 releasing PLGA MPs with naïve CD4⁺ T cells resulted in the efficient generation of both polyclonal and antigen-specific induced regulatory T cells (iTregs) with robust immunosuppressive function. The co-transplantation of TGF-β1 releasing PLGA MPs and Balb/c mouse islets within the extrahepatic epididymal fat pad (EFP) of diabetic C57BL/6J mice resulted in the prompt engraftment of the allogenic implants, supporting the compatibility of PLGA MPs and local TGF-β1 release. The presence of the TGF-β1-PLGA MPs, however, did not confer significant graft protection when compared to untreated controls, despite measurement of preserved insulin expression, reduced intra-islet CD3⁺ cells invasion, and elevated CD3⁺Foxp3⁺ T cells at the peri-transplantation site in long-term functioning grafts. Examination of the broader impacts of TGF-β1/PLGA MPs on the host immune system implicated a localized nature of the immunomodulation with no observed systemic impacts. In summary, this approach establishes the feasibility of a local and modular microparticle delivery system for the immunomodulation of an extrahepatic implant site. This approach can be easily adapted to deliver larger doses or other agents, as well as multi-drug approaches, within the local graft microenvironment to prevent transplant rejection.