Pharmacology of drugs formulated with DepoFoam: a sustained release drug delivery system for parenteral administration using multivesicular liposome technology

Drug delivery in leptomeningeal disease: Navigating barriers and beyond

Leptomeningeal disease (LMD) refers to the infiltration of cancer cells into the leptomeningeal compartment. Leptomeninges are the two membranous layers, called the arachnoid membrane and pia mater. The diffuse nature of LMD poses a challenge to its effective diagnosis and successful management. Furthermore, the predominant phenotype; solid masses or freely floating cells, has altering implications on the effectiveness of drug delivery systems. The standard of care is the intrathecal delivery of chemotherapy drugs but it is associated with increased instances of treatment-related complications, low patient compliance, and suboptimal drug distribution. An alternative involves administering the drugs systemically, after which they must traverse fluid barriers to arrive at their destination within the leptomeningeal space. However, this route is known to cause off-target effects as well as produce subtherapeutic drug concentrations at the target site within the central nervous system. The development of new drug delivery systems such as liposomal cytarabine has improved drug delivery in leptomeningeal metastatic disease, but much still needs to be done to effectively target this challenging condition. In this review, we discuss about the anatomy of leptomeninges relevant for drug penetration, the conventional and advanced drug delivery methods for LMD. We also discuss the future directions being set by different clinical trials.

Nanoparticle-mediated thermal Cancer therapies: Strategies to improve clinical translatability

Despite significant advances, cancer remains a leading global cause of death. Current therapies often fail due to incomplete tumor removal and nonspecific targeting, spurring interest in alternative treatments. Hyperthermia, which uses elevated temperatures to kill cancer cells or boost their sensitivity to radio/chemotherapy, has emerged as a promising alternative. Recent advancements employ nanoparticles (NPs) as heat mediators for selective cancer cell destruction, minimizing damage to healthy tissues. This approach, known as NP hyperthermia, falls into two categories: photothermal therapies (PTT) and magnetothermal therapies (MTT). PTT utilizes NPs that convert light to heat, while MTT uses magnetic NPs activated by alternating magnetic fields (AMF), both achieving localized tumor damage. These methods offer advantages like precise targeting, minimal invasiveness, and reduced systemic toxicity. However, the efficacy of NP hyperthermia depends on many factors, in particular, the NP properties, the tumor microenvironment (TME), and TME-NP interactions. Optimizing this treatment requires accurate heat monitoring strategies, such as nanothermometry and biologically relevant screening models that can better mimic the physiological features of the tumor in the human body. This review explores the state-of-the-art in NP-mediated cancer hyperthermia, discussing available nanomaterials, their strengths and weaknesses, characterization methods, and future directions. Our particular focus lies in preclinical NP screening techniques, providing an updated perspective on their efficacy and relevance in the journey towards clinical trials.

Rational formulation and industrial manufacturing of lipid-based complex injectables: Landmarks and trends

Lipid-based complex injectables are renowned for their effectiveness in delivering drugs, with many approved products. While significant strides have been made in formulating nanosystems for small molecular weight drugs, a pivotal breakthrough emerged with the recognition of lipid nanoparticles as a promising platform for delivering nucleic acids. This finding has paved the way for tackling long-standing challenges in molecular and delivery aspects (e.g., mRNA stability, intracellular delivery) that have impeded the clinical translation of gene therapy, especially in the realm of immunotherapy. Nonetheless, developing and implementing new lipid-based delivery systems pose significant challenges, as industrial manufacturing of these formulations often involves complex, multi-batch processes, giving rise to issues related to scalability, stability, sterility, and regulatory compliance. To overcome these obstacles, embracing the principles of quality-by-design (QbD) is imperative. Furthermore, adopting cutting-edge manufacturing and process analytical tools (PAT) that facilitate the transition from batch to continuous production is essential. Herein, the key milestones and insights derived from the development of currently approved lipid- nanosystems will be explored. Additionally, a comprehensive and critical overview of the latest technologies and regulatory guidelines that underpin the creation of more efficient, scalable, and flexible manufacturing processes for complex lipid-based nanoformulations will be provided.

Extended Release of Bupivacaine from Temperature-Responsive PNDJ Hydrogels Improves Postoperative Weight-Bearing in Rabbits Following Knee Surgery

Effective treatment of postoperative pain lasting for multiple days without opioids is an important clinical need. We previously reported analgesia lasting up to 96 h in a porcine soft tissue model of postoperative pain using SBG004, an extended-release formulation of bupivacaine based on the temperature-responsive polymer poly(N-isopropylacrylamide-co-dimethylbutyrolactone acrylamide-co-Jeffamine M-1000 acrylamide) [PNDJ]. Orthopaedic surgical sites such as the knee can involve complex sensory innervation which presents a distinct challenge to local anesthetic delivery. The purpose of this work was to evaluate the pharmacokinetics and efficacy of SBG004 in an orthopaedic surgical model in comparison to currently available local anesthetics. Pharmacokinetics following periarticular (PA) or intraarticular (IA) injection of SBG004 were compared against liposomal bupivacaine (Lip-Bupi) PA in New Zealand White rabbits (all doses 14.5 mg/kg). Analgesic efficacy of SBG004 (IA, PA, or IA + PA), three active comparators, and saline was evaluated following knee surgery in New Zealand White rabbits. Analgesia was assessed via weight-bearing on the operated limb during spontaneous large steps in video recordings. Systemic bupivacaine exposure lasted at least 7 days for SBG004 PA, 4 days for SBG004 IA, and 2 days for Lip-Bupi PA. In the analgesia study, weight-bearing in all active groups except SBG004 IA was more frequent versus saline through 8 h postoperatively (p < 0.05). Only SBG004 IA + PA resulted in a higher proportion of weight-bearing rabbits at 24 h versus saline (6/7 versus 2/10, p = 0.015). Analysis of pooled data from 24-72 h showed significantly greater frequency of weight-bearing in rabbits receiving SBG004 IA + PA (71%) versus saline (37%), ropivacaine cocktail (41%), and Lip-Bupi PA (36%). The results indicate that the release profile from SBG004 PA or IA coincides reasonably with the time course of postoperative pain, and SBG004 may produce longer duration of analgesia than local anesthetics currently used in knee surgery, including during the period of 24-72 h recognized as a target for extended-release local anesthetics.

Effect of liposomal bupivacaine for preoperative erector spinae plane block on postoperative pain following video-assisted thoracoscopic lung surgery: a protocol for a multicenter, randomized, double-blind, clinical trial

Background

There is still a controversy about the superiority of liposomal bupivacaine (LB) over traditional local anesthetics in postoperative analgesia after thoracic surgery. This study aims to determine the effect of LB versus bupivacaine hydrochloride (HCl) for preoperative ultrasound-guided erector spinae plane block (ESPB) on postoperative acute and chronic pain in patients undergoing video-assisted thoracoscopic lung surgery.

Methods

This multicenter, randomized, double-blind, controlled trial will include 272 adult patients scheduled for elective video-assisted thoracoscopic lung surgery. Patients will be randomly assigned, 1:1 and stratified by site, to the liposomal bupivacaine (LB) group or the bupivacaine (BUPI) HCl group. All patients will receive ultrasound-guided ESPB with either LB or bupivacaine HCl before surgery and patient-controlled intravenous analgesia (PCIA) as rescue analgesia after surgery. The numeric rating scale (NRS) score will be assessed after surgery. The primary outcome is the area under the curve of pain scores at rest for 0-72 h postoperatively. The secondary outcomes include the total amount of opioid rescue analgesics through 0-72 h postoperatively, time to the first press on the PCIA device as rescue analgesia, the area under the curve of pain scores on activity for 0-72 h postoperatively, NRS scores at rest and on activity at different time points during the 0-72 h postoperative period, Quality of Recovery 15 scores at 72 h after surgery, and NRS scores on activity on postsurgical day 14 and postsurgical 3 months. Adverse events after the surgery are followed up to the postsurgical day 7, including postoperative nausea and vomiting, fever, constipation, dizziness, headache, insomnia, itching, prolonged chest tube leakage, new-onset atrial fibrillation, severe ventricular arrhythmia, deep venous thrombosis, pulmonary embolism, pulmonary atelectasis, cardiac arrest, ileus, urinary retention, chylothorax, pneumothorax, and organ failure. Analyzes will be performed first according to the intention to treat principle and second with the per-protocol analysis.

Discussion

We hypothesize that LB for preoperative ultrasound-guided ESPB would be more effective than bupivacaine HCl in reducing postoperative pain in video-assisted thoracoscopic lung surgery. Our results will contribute to the optimization of postoperative analgesia regimens for patients undergoing video-assisted thoracoscopic lung surgery.Clinical trial registration:http://www.chictr.org.cn, identifier ChiCTR2300074852.

Microencapsulation for Pharmaceutical Applications: A Review

In order to improve bioavailability, stability, control release, and target delivery of active pharmaceutical ingredients (APIs), as well as to mask their bitter taste, to increase their efficacy, and to minimize their side effects, a variety of microencapsulation (including nanoencapsulation, particle size <100 nm) technologies have been widely used in the pharmaceutical industry. Commonly used microencapsulation technologies are emulsion, coacervation, extrusion, spray drying, freeze-drying, molecular inclusion, microbubbles and microsponge, fluidized bed coating, supercritical fluid encapsulation, electro spinning/spray, and polymerization. In this review, APIs are categorized by their molecular complexity: small APIs (compounds with low molecular weight, like Aspirin, Ibuprofen, and Cannabidiol), medium APIs (compounds with medium molecular weight like insulin, peptides, and nucleic acids), and living microorganisms (such as probiotics, bacteria, and bacteriophages). This article provides an overview of these microencapsulation technologies including their processes, matrix, and their recent applications in microencapsulation of APIs. Furthermore, the advantages and disadvantages of these common microencapsulation technologies in terms of improving the efficacy of APIs for pharmaceutical treatments are comprehensively analyzed. The objective is to summarize the most recent progresses on microencapsulation of APIs for enhancing their bioavailability, control release, target delivery, masking their bitter taste and stability, and thus increasing their efficacy and minimizing their side effects. At the end, future perspectives on microencapsulation for pharmaceutical applications are highlighted.

Intrathecal delivery of nanoparticle PARP inhibitor to the cerebrospinal fluid for the treatment of metastatic medulloblastoma

The morbidity associated with pediatric medulloblastoma, in particular in patients who develop leptomeningeal metastases, remains high in the absence of effective therapies. Administration of substances directly into the cerebrospinal fluid (CSF) is one approach to circumvent the blood-brain barrier and focus delivery of drugs to the site of tumor. However, high rates of CSF turnover prevent adequate drug accumulation and lead to rapid systemic clearance and toxicity. Here, we show that PLA-HPG nanoparticles, made with a single-emulsion, solvent evaporation process, can encapsulate talazoparib, a PARP inhibitor (BMN-673). These degradable polymer nanoparticles improve the therapeutic index when delivered intrathecally and lead to sustained drug retention in the tumor as measured with PET imaging and fluorescence microscopy. We demonstrate that administration of these particles into the CSF, alone or in combination with systemically administered temozolomide, is a highly effective therapy for tumor regression and prevention of leptomeningeal spread in xenograft mouse models of medulloblastoma. These results provide a rationale for harnessing nanoparticles for the delivery of drugs limited by brain penetration and therapeutic index and demonstrate important advantages in tolerability and efficacy for encapsulated drugs delivered locoregionally.

Recent advances in lipid-based long-acting injectable depot formulations

Long-acting injectable (LAIs) delivery systems sustain the drug therapeutic action in the body, resulting in reduced dosage regimen, toxicity, and improved patient compliance. Lipid-based depots are biocompatible, provide extended drug release, and improve drug stability, making them suitable for systemic and localized treatment of various chronic ailments, including psychosis, diabetes, hormonal disorders, arthritis, ocular diseases, and cancer. These depots include oil solutions, suspensions, oleogels, liquid crystalline systems, liposomes, solid lipid nanoparticles, nanostructured lipid carriers, phospholipid phase separation gel, vesicular phospholipid gel etc. This review summarizes recent advancements in lipid-based LAIs for delivering small and macromolecules, and their potential in managing chronic diseases. It also provides an overview of the lipid depots available in market or clinical phase, as well as patents for lipid-based LAIs. Furthermore, this review critically discusses the current scenario of using in vitro release methods to establish IVIVC and highlights the challenges involved in developing lipid-based LAIs.

Characterization of exparel bupivacaine multivesicular liposomes

Exparel is a bupivacaine multivesicular liposomes (MVLs) formulation developed based on the DepoFoam technology. The complex composition and the unique structure of MVLs pose challenges to the development and assessment of generic versions. In the present work, we developed a panel of analytical methods to characterize Exparel with respect to particle size, drug and lipid content, residual solvents, and pH. In addition, an accelerated in vitro drug release assay was developed using a rotator-facilitated, sample-and-separate experimental setup. The proposed method could achieve over 80% of bupivacaine release within 24 h, which could potentially be used for formulation comparison and quality control purposes. The batch-to-batch variability of Exparel was examined by the established analytical methods. Four different batches of Exparel showed good batch-to-batch consistency in drug content, particle size, pH, and in vitro drug release kinetics. However, slight variation in lipid contents were observed.

The use of liposomal bupivacaine in fracture surgery: a review

Historically, opioids have played a major role in the treatment of postoperative pain in orthopedic surgery. A multitude of adverse events have been associated with opioid use and alternative approaches to pain relief are being investigated, with particular focus on multimodal pain management regimens. Liposomal bupivacaine (EXPAREL) is a component of some multimodal regimens. This formulation of bupivacaine encapsulates the local anesthetic into a multivesicular liposome to theoretically deliver a consistent amount of drug for up to 72 hours. Although the use of liposomal bupivacaine has been studied in many areas of orthopedics, there is little evidence evaluating its use in patients with fractures. This systematic review of the available data identified a total of eight studies evaluating the use of liposomal bupivacaine in patients with fractures. Overall, these studies demonstrated mixed results. Three studies found no difference in postoperative pain scores on postoperative days 1-4, while two studies found significantly lower pain scores on the day of surgery. Three of the studies evaluated the quantity of narcotic consumption postoperatively and failed to find a significant difference between control groups and groups treated with liposomal bupivacaine. Further, significant variability in comparison groups and study designs made interpretation of the available data difficult. Given this lack of clear evidence, there is a need for prospective, randomized clinical trials focused on fully evaluating the use of liposomal bupivacaine in fracture patients. At present, clinicians should maintain a healthy skepticism and rely on their own interpretation of the available data before widely implementing the use of liposomal bupivacaine.

Nanoparticles as Drug Delivery Systems: A Review of the Implication of Nanoparticles' Physicochemical Properties on Responses in Biological Systems

In the last four decades, nanotechnology has gained momentum with no sign of slowing down. The application of inventions or products from nanotechnology has revolutionised all aspects of everyday life ranging from medical applications to its impact on the food industry. Nanoparticles have made it possible to significantly extend the shelf lives of food product, improve intracellular delivery of hydrophobic drugs and improve the efficacy of specific therapeutics such as anticancer agents. As a consequence, nanotechnology has not only impacted the global standard of living but has also impacted the global economy. In this review, the characteristics of nanoparticles that confers them with suitable and potentially toxic biological effects, as well as their applications in different biological fields and nanoparticle-based drugs and delivery systems in biomedicine including nano-based drugs currently approved by the U.S. Food and Drug Administration (FDA) are discussed. The possible consequence of continuous exposure to nanoparticles due to the increased use of nanotechnology and possible solution is also highlighted.

Peripheral Regional Anesthesia Using Local Anesthetics: Old Wine in New Bottles?

During the past decade, numerous efforts were undertaken aiming at prolonging the analgesic effect of regional anesthesia. With the development of extended-release formulations and enhanced selectivity for nociceptive sensory neurons, a very promising contribution to the development of pain medications has been achieved. At present, liposomal bupivacaine is the most popular, non-opioid, controlled drug delivery system, but its duration of action, which is still controversially discussed, and its expensiveness have decreased initial enthusiasm. Continuous techniques can be seen as an elegant alternative for providing a prolonged duration of analgesia, but for logistic or anatomical reasons, they are not always the best choice. Therefore, focus has been directed towards the perineural and/or intravenous addition of old and established substances. As for perineural application, most of these so-called 'adjuvants' are used outside their indication, and their pharmacological efficacy is often not or only poorly understood. This review aims to summarize the recent developments for prolonging the duration of regional anesthesia. It will also discuss the potential harmful interactions and side effects of frequently used analgesic mixtures.

Development and in vivo validation of phospholipid-based depots for the sustained release of bupivacaine

By direct deposition of the drug at the local site of action, injectable depot formulations - intended for treatment of a local disease or for local intervention - are designed to limit the immediate exposure of the active principle at a systemic level and to reduce the frequency of administration. To overcome known drawbacks in the production of some marketed phospholipid-based depots, here we propose to manufacture drug-loaded negatively charged liposomes through conventional technologies and to control their aggregation mixing a solution of divalent cations prior to administration. We identified phosphatidylglycerol (PG) as the most suitable phospholipid for controlled aggregation of the liposomes and to modulate the release of the anesthetic bupivacaine (BUP) from liposomal depots. In vivo imaging of the fluorescently-labelled liposomes showed a significantly higher retention of the PG liposomes at the injection site with respect to zwitterionic ones. In situ mixing of PG liposomes with calcium salts significantly extended the area under the curve of BUP in plasma compared to the non-depot system. Overall, controlling the aggregation of negatively charged liposomes with divalent cations not only modulated the particle clearance from the injection site but also the release in vivo of a small amphipathic drug such as BUP.

Liposomes: structure, composition, types, and clinical applications

Liposomes are now considered the most commonly used nanocarriers for various potentially active hydrophobic and hydrophilic molecules due to their high biocompatibility, biodegradability, and low immunogenicity. Liposomes also proved to enhance drug solubility and controlled distribution, as well as their capacity for surface modifications for targeted, prolonged, and sustained release. Based on the composition, liposomes can be considered to have evolved from conventional, long-circulating, targeted, and immune-liposomes to stimuli-responsive and actively targeted liposomes. Many liposomal-based drug delivery systems are currently clinically approved to treat several diseases, such as cancer, fungal and viral infections; more liposomes have reached advanced phases in clinical trials. This review describes liposomes structure, composition, preparation methods, and clinical applications.

Efficacy of Liposomal Bupivacaine and Bupivacaine Hydrochloride vs Bupivacaine Hydrochloride Alone as a Periarticular Anesthetic for Patients Undergoing Knee Replacement: A Randomized Clinical Trial

Question

Among patients undergoing knee replacement surgery, does liposomal bupivacaine and bupivacaine hydrochloride administered at the surgical site improve postoperative recovery at 72 hours and postoperative pain from 6 to 72 hours compared with bupivacaine hydrochloride alone?

Findings

In this randomized clinical trial of 533 patients undergoing knee replacement surgery, no difference in the coprimary outcomes of Quality of Recovery 40 score at 72 hours or pain visual analog scale score area under the curve from 6 to 72 hours was detected between patients receiving liposomal bupivacaine and bupivacaine hydrochloride and those receiving bupivacaine hydrochloride alone. In addition, liposomal bupivacaine was not found to be cost-effective.

Meaning

This study found that liposomal bupivacaine did not improve postoperative recovery or pain compared with bupivacaine hydrochloride alone among patients undergoing knee replacement surgery.

Importance

More than half of patients who undergo knee replacement surgery report substantial acute postoperative pain.

Objective

To evaluate the efficacy and cost-effectiveness of periarticular liposomal bupivacaine for recovery and pain management after knee replacement.

Design, Setting, and Participants

This multicenter, patient-blinded, pragmatic, randomized clinical superiority trial involved 533 participants at 11 institutions within the National Health Service in England. Adults undergoing primary unilateral knee replacement for symptomatic end-stage osteoarthritis were enrolled between March 29, 2018, and February 29, 2020, and followed up for 1 year after surgery. Follow-up was completed March 1, 2021. A per-protocol analysis for each coprimary outcome was performed in addition to the main intention-to-treat analysis.

Interventions

Two hundred sixty-six milligrams of liposomal bupivacaine admixed with 100 mg of bupivacaine hydrochloride compared with 100 mg of bupivacaine hydrochloride alone (control) administered by periarticular injection at the time of surgery.

Main Outcome and Measures

The coprimary outcomes were Quality of Recovery 40 (QoR-40) score at 72 hours and pain visual analog scale (VAS) score area under the curve (AUC) from 6 to 72 hours. Secondary outcomes included QoR-40 and mean pain VAS at days 0 (evening of surgery), 1, 2, and 3; cumulative opioid consumption for 72 hours; functional outcomes and quality of life at 6 weeks, 6 months, and 1 year; and cost-effectiveness for 1 year. Adverse events and serious adverse events up to 12 months after randomization were also assessed.

Results

Among the 533 participants included in the analysis, the mean (SD) age was 69.0 (9.7) years; 287 patients were women (53.8%) and 246 were men (46.2%). Baseline characteristics were balanced between study groups. There was no difference between the liposomal bupivacaine and control groups in QoR-40 score at 72 hours (adjusted mean difference, 0.54 [97.5% CI, −2.05 to 3.13]; P = .64) or the pain VAS score AUC at 6 to 72 hours (−21.5 [97.5% CI, −46.8 to 3.8]; P = .06). Analyses of pain VAS and QoR-40 scores demonstrated only 1 statistically significant difference, with the liposomal bupivacaine arm having lower pain scores the evening of surgery (adjusted difference −0.54 [97.5% CI, −1.07 to −0.02]; P = .02). No difference in cumulative opioid consumption and functional outcomes was detected. Liposomal bupivacaine was not cost-effective compared with the control treatment. No difference in adverse or serious adverse events was found between the liposomal bupivacaine and control groups.

Conclusions and Relevance

This study found no difference in postoperative recovery or pain associated with the use of periarticular liposomal bupivacaine compared with bupivacaine hydrochloride alone in patients who underwent knee replacement surgery.

Trial Registration

isrctn.com Identifier: ISRCTN54191675

Liposomal Bupivacaine Infiltration Versus Bupivacaine Hydrochloride for the Management of Unilateral Total Knee Arthroplasty in Geriatric Patients at a 287-Bed Community Hospital

Introduction: Geriatric patients receiving total knee arthroplasty (TKA) are found to have similar postoperative complications, functional scores, and perioperative mortality, as compared to younger patients. Conversely, geriatric patients often have longer lengths of stay. Periarticular injection (PAI) of liposomal bupivacaine (LB) as part of the multimodal pain management strategy is thought to improve recovery, however, mixed comparative efficacy data exists for its use in TKA.2-5. Methods: A retrospective, chart review was conducted at a 287-bed community teaching hospital. Orthopedic surgical patients who received an infiltration with liposomal bupivacaine versus bupivacaine HCl for unilateral TKA were compared. Patients identified in the electronic medical record by Diagnosis Related Group (DRG) 470-major joint replacement or reattachment of lower extremity without major complication or comorbidity codes were utilized. Patients who meet the following criteria were included: age 65 and older who underwent a TKA between 8/1/2018 to 7/31/2019 were discharged to home. Patients who have contraindications or hypersensitivity to bupivacaine formulations or a history of opioid dependence were excluded. The primary outcome is to identify whether patients who received an infiltration with liposomal bupivacaine had a lower total opioid consumption during their hospital stay. Results: A total of 114 patients who had a DRG 470 code and were above the age of 65 years were studied. There was no statistically significant difference in mean total opioid consumption (oral morphine equivalents) between the bupivacaine HCl (n = 25) and liposomal groups (n = 85) respectively, 93.76 versus 83.72 mg; P = .569. In addition, patients in both groups had similar lengths of hospital stay, 2.5 versus 3 days; P = .529 and mean pain scores until discharge 3.7 versus 4.34 on VAS; P = .305. Conclusion: The results of this drug utilization evaluation do not support a strong clinical advantage with local infiltration of liposomal bupivacaine over bupivacaine HCl in geriatric patients undergoing primary TKA surgery at this institution. There was not a statistically significant difference in mean total opioid consumption between the 2 groups. Additionally, the use of non-opioid analgesics, mean pain scores, and hospital lengths of stay were similar in both groups.

A review on multivesicular liposomes for pharmaceutical applications: preparation, characterization, and translational challenges

Multivesicular liposomes (MVLs) are non-concentric, lipid-based micron-sized spherical particles. The usage of MVL for sustained drug delivery has seen progression over the last decade due to successful clinical and commercial applications. It provides attractive characteristics, such as high encapsulation efficiency, variety of sizes, structural stability, and different choices for the route of administration. Drug molecules are encapsulated in internal aqueous compartments of MVL, separated by lipid bilayer septa to form polyhedral structures. The integrity of these entrapped small molecules, peptides, or proteins is maintained throughout the therapy, thus providing sustained drug release on non-vascular administration. Despite the frequent use of unilamellar liposomes, characterization of MVLs is critical due to different puzzling problems, such as real-time size evaluation, initial burst, and in vivo performance. Moreover, available regulatory guidelines on liposomal drug product development are insufficient to assure ample in vitro-in vivo behavior of MVL. This review hereby highlights the innovations pertaining to development and manufacturing procedures, drug release mechanisms, and characterization techniques. The review also summarizes the applications, challenges, and future perspectives for successfully translating the research concept to a clinically accepted delivery system. Despite the intricacies involved in the development of MVL, establishing steadfast characterization techniques and regulatory paths could pave the way to its extensive clinical use.

Multivesicular liposome: A lipid-based drug delivery system for efficient drug delivery

The advancement of delivery tools for therapeutic agents has brought several novel formulations with increased drug loading, sustained release, targeted delivery, and prolonged efficacy. Amongst the several novel delivery approaches, multivesicular liposome has gained potential interest because this delivery system possesses the above advantages. In addition, this multivesicular liposomal delivery prevents degradation of the entrapped drug within the physiological environment while administered. The special structure of the vesicles allowed successful entrapment of hydrophobic and hydrophilic therapeutic agents, including proteins and peptides. Furthermore, this novel formulation could maintain the desired drug concentration in the plasma for a prolonged period, which helps to reduce the dosing frequencies, improve bioavailability, and safety. This tool could also provide stability of the formulation, and finally gaining patient compliance. Several multivesicular liposomes received approval for clinical research, while others are at different stages of laboratory research. In this review, we have focused on the preparation of multivesicular liposomes along with their application in different ailments for the improvement of the performance of the entrapped drug. Moreover, the challenges of delivering multivesicular vesicles have also been emphasized. Overall, it could be inferred that multivesicular liposomal delivery is a novel platform of advanced drug delivery with improved efficacy and safety.

N-acetylgalactosamine-decorated nanoliposomes for targeted delivery of paclitaxel to hepatocellular carcinoma

In this study, we designed and developed a novel asialoglycoprotein receptor (ASGPR)-targeted PEGylated paclitaxel (PTX) nanoliposome for hepatocellular carcinoma (HCC). N-acetylgalactosamine with α configuration (Tn) was synthesized and used as the active targeting ligand. Notably, Tn modified nanoliposomes loaded with PTX (Tn-Lipo-PTX) showed a narrow distribution (PDI = 0.18-0.20) with 74 ± 0.36 nm of average sizes. Tn-Lipo-PTX has a high encapsulation efficiency of more than 93.0% and 13% of drug loading (DL). Compared with no targeted Con-Lipo-PTX, Tn-Lipo-PTX showed lower and sustained release characteristic in PBS in vitro. Tn targeting ASGPR was confirmed by HepG-2 cells uptake experiment by fluorescence microscopy analysis. Tn-Lipo-PTX accumulated in HepG-2 cells and this process was inhibited by adding Tn ligand, supporting receptor-mediated endocytosis mechanism. MTT assays was implemented in four cell lines. Tn-Lipo-PTX exhibited superior inhibition against ASGPR on over-expressing HepG-2 (IC₅₀ = 1.93 nM). The cell cycle experiments showed that Tn-Lipo-PTX could efficiently increase the percentage of cells arrest in the G2/M phase. Through western blotting analysis, the β-tubulin and cyclin B1 expression in the Tn-Lipo-PTX group were significantly higher compared with other groups and the CDK1 was down-regulated compared with PTX group, which indicated that targeting liposome delivery system could not only change periodic proteins expression, but also improve the killing effect of PTX on hepatocarcinoma cell. Tn-installed PEGylated nanoliposomes have a great potential for targeted cancer chemotherapy.

Targeted liposomal drug delivery: a nanoscience and biophysical perspective

Liposomes are a unique platform for drug delivery, and a number of liposomal formulations have already been commercialized. Doxil is a representative example, which uses PEGylated liposomes to load doxorubicin for cancer therapy. Its delivery relies on the enhanced permeability and retention (EPR) effect or passive targeting. Drug loading can be achieved using both standard liposomes and also those containing a solid core such as mesoporous silica and poly(lactide-co-glycolide) (PLGA). Developments have also been made on active targeted delivery using bioaffinity ligands such as small molecules, antibodies, peptides and aptamers. Compared to other types of nanoparticles, the surface of liposomes is fluid, allowing dynamic organization of targeting ligands to achieve optimal binding to cell surface receptors. This review article summarizes development of liposomal targeted drug delivery systems, with an emphasis on the biophysical properties of lipids. In both passive and active targeting, the effects of liposome size, charge, fluidity, rigidity, head-group chemistry and PEGylation are discussed along with recent examples. Most of the examples are focused on targeting tumors or cancer cells. Finally, a few examples of commercialized formulations are described, and some future research opportunities are discussed.

Multivesicular Liposome (Depofoam) in Human Diseases

Drug development is a key point in the research of new therapeutic treatments for increasing maximum drug loading and prolonged drug effect. Encapsulation of drugs into multivesicular liposomes (DepoFoam) is a nanotechnology that allow delivery of the active constituent at a sufficient concentration during the entire treatment period. This guarantees the reduction of drug administration frequency, a very important factor in a prolonged treatment. Currently, diverse DepoFoam drugs are approved for clinical use against neurological diseases and for post-surgical pain management while other are under development for reducing surgical bleeding and for post-surgical analgesia. Also, on pre-clinical trials on cancer DepoFoam can improve bioavailability and stability of the drug molecules minimizing side effects by site-specific targeted delivery. In the current work, available literature on structure, preparation and pharmacokinetics of DepoFoam are reviewed. Moreover, we investigated approved DepoFoam formulations and preclinical studies with this nanotechnology.

Nicardipine Loaded Solid Phospholipid Extrudates for the Prevention of Cerebral Vasospasms: In Vitro Characterization

The aim of the study was to develop nicardipine loaded phospholipid extrudates as an alternative for PLA/PLGA-based implants for the prevention of cerebral vasospasms. Extrudates of different mixtures of saturated and unsaturated phosphatidylcholine (PC) were produced and characterized by DSC, microscopy and texture analysis. Single phospholipid components were identified by ELSD-HPLC. Extrudates of 2 mm diameter were obtained by twin screw extrusion temperatures below 50 °C. The ratio of unsaturated and saturated phosphatidylcholine components determines the physicochemical properties of the extrudates as well as the rate of erosion. Nicardipine loaded phospholipids extrudates released the drug over several weeks in vitro. The phospholipid composition of the remaining extrudate changed during the release, the content of unsaturated phospholipids decreased faster compared to the saturated ones. In conclusion, solid phospholipid extrudates are promising materials for the development of new parenteral controlled release systems.

Recent advancements in liposome technology

The liposomes have continued to be well-recognized as an important nano-sized drug delivery system with attractive properties, such a characteristic bilayer structure assembling the cellular membrane, easy-to-prepare and high bio-compatibility. Extensive effort has been devoted to the development of liposome-based drug delivery systems during the past few decades. Many drug candidates have been encapsulated in liposomes and investigated for reduced toxicity and extended duration of therapeutic effect. The liposomal encapsulation of hydrophilic and hydrophobic small molecule therapeutics as well as other large molecule biologics have been established among different academic and industrial research groups. To date, there has been an increasing number of FDA-approved liposomal-based therapeutics together with more and more undergoing clinical trials, which involve a wide range of applications in anticancer, antibacterial, and antiviral therapies. In order to meet the continuing demand for new drugs in clinics, more recent advancements have been investigated for optimizing liposomal-based drug delivery system with more reproducible preparation technique and a broadened application to novel modalities, including nucleic acid therapies, CRISPR/Cas9 therapies and immunotherapies. This review focuses on the recent liposome' preparation techniques, the excipients of liposomal formulations used in various novel studies and the routes of administration used to deliver liposomes to targeted areas of disease. It aims to update the research in liposomal delivery and highlights future nanotechnological approaches.

Injectable Lipid-Based Depot Formulations: Where Do We Stand?

The remarkable number of new molecular entities approved per year as parenteral drugs, such as biologics and complex active pharmaceutical ingredients, calls for innovative and tunable drug delivery systems. Besides making these classes of drugs available in the body, injectable depot formulations offer the unique advantage in the parenteral world of reducing the number of required injections, thus increasing effectiveness as well as patient compliance. To date, a plethora of excipients has been proposed to formulate depot systems, and among those, lipids stand out due to their unique biocompatibility properties and safety profile. Looking at the several long-acting drug delivery systems based on lipids designed so far, a legitimate question may arise: How far away are we from an ideal depot formulation? Here, we review sustained release lipid-based platforms developed in the last 5 years, namely oil-based solutions, liposomal systems, in situ forming systems, solid particles, and implants, and we critically discuss the requirements for an ideal depot formulation with respect to the used excipients, biocompatibility, and the challenges presented by the manufacturing process. Finally, we delve into lights and shadows originating from the current setups of in vitro release assays developed with the aim of assessing the translational potential of depot injectables.

Pharmacokinetics of multivesicular liposomal encapsulated cytarabine when administered subcutaneously in dogs

Background

Prolonged cytotoxic concentrations of cytarabine (CA) are required for maximum cytotoxicity. DepoCyt is a human liposomal cytarabine (LC) product that lasts longer in plasma and CSF compared with free CA (FC). The use of LC has not been evaluated in dogs.

Objectives

To perform a LC pharmacokinetic (PK) study when administered SC in dogs.

Animals

Five healthy female beagles.

Methods

Three‐period, 3‐treatment, nonblinded, randomized, and crossover design, including a pilot study. LC was administered at 50 mg/m² SC and FC was administered at 25 and 50 mg/m² SC and IV. Plasma CA concentrations were measured until 240, 72, and 8 hours after SC LC, SC FC, and IV FC administration, respectively. CA plasma concentrations were quantitated by ultra‐high‐performance liquid chromatography with mass spectrometry (MS/MS) detection and concentration‐time profiles were evaluated by noncompartmental analysis.

Results

Subcutaneous LC administration resulted in a maximum plasma concentration of 26.3 to 59.78 ng/mL, time to reach maximum plasma concentration of 2 hours, area under the concentration‐time curve to last measurable concentration of 669.3 to 1126 h × ng/mL, and plasma bioavailability (%F) of 19.6% to 31.3%. The PK profiles of FC after SC and IV administration differed when compared with LC.

Conclusions and Clinical Importance

In healthy dogs, SC LC administration at 50 mg/m² results in measurable plasma CA concentrations, is apparently safe and well tolerated, but does not result in prolonged cytotoxic plasma concentrations. Poor absorption of LC prevented establishment of a complete LC PK profile.

Advances of Nano-Structured Extended-Release Local Anesthetics

Extended-release local anesthetics (LAs) have drawn increasing attention with their promising role in improving analgesia and reducing adverse events of LAs. Nano-structured carriers such as liposomes and polymersomes optimally meet the demands of/for extended-release, and have been utilized in drug delivery over decades and showed satisfactory results with extended-release. Based on mature technology of liposomes, EXPAREL, the first approved liposomal LA loaded with bupivacaine, has seen its success in an extended-release form. At the same time, polymersomes has advances over liposomes with complementary profiles, which inspires the emergence of hybrid carriers. This article summarized the recent research successes on nano-structured extended-release LAs, of which liposomal and polymeric are mainstream systems. Furthermore, with continual optimization, drug delivery systems carry properties beyond simple transportation, such as specificity and responsiveness. In the near future, we may achieve targeted delivery and controlled-release properties to satisfy various analgesic requirements.

Study of Peri-Articular Anaesthetic for Replacement of the Knee (SPAARK): study protocol for a patient-blinded, randomised controlled superiority trial of liposomal bupivacaine

Background

Optimising the management of peri-operative pain and recovery following knee replacement has been identified as a patient priority. Current pain relief strategies use opiate-based analgesia; however, up to 50% of patients experience significant side effects. Local anaesthetic incisional infiltration is one alternative. The length of the duration of action is a major limiting factor of current local anaesthetic techniques. Liposomal bupivacaine has been reported to be effective for up to 72 h. This randomised controlled trial will evaluate the clinical and cost effectiveness of liposomal bupivacaine.

Methods

SPAARK is a patient-blinded, multi-centre, active comparator, superiority, two-arm, parallel-group randomised controlled trial. Five hundred patients undergoing knee replacement will be recruited and randomised to liposomal bupivacaine plus bupivacaine hydrochloride or bupivacaine hydrochloride alone. The co-primary outcomes are the Quality of Recovery 40 measured at 72 h post-surgery and also cumulative pain measured daily using a 0–10 visual analogue scale for the first 3 days following surgery. Secondary outcomes include cumulative opioid consumption, fitness for discharge, functional outcomes assessed using the Oxford Knee Score and American Knee Society Score, the EuroQol five dimensions instrument and complications. A cost utility analysis is also planned.

Discussion

The clinical effectiveness and cost effectiveness of liposomal bupivacaine have yet to be evaluated in the National Health Service, making this trial appropriate and timely.

Trial registration

ISRCTN registry, ISRCTN54191675. Registered on 14 November 2017.

Controlled deprotection and release of a small molecule from a compartmented synthetic tissue module

Synthetic tissues built from communicating aqueous droplets offer potential applications in biotechnology, however, controlled release of their contents has not been achieved. Here we construct two-droplet synthetic tissue modules that function in an aqueous environment. One droplet contains a cell-free protein synthesis system and a prodrug-activating enzyme and the other a small-molecule prodrug analog. When a Zn2+-sensitive protein pore is made in the first droplet, it allows the prodrug to migrate from the second droplet and become activated by the enzyme. With Zn2+ in the external medium, the activated molecule is retained in the module until it is released on-demand by a divalent cation chelator. The module is constructed in such a manner that one or more, potentially with different properties, might be incorporated into extended synthetic tissues, including patterned materials generated by 3D-printing. Such modules will thereby increase the sophistication of synthetic tissues for applications including controlled multidrug delivery.

Mileski K, Pezzani R, Redaelli M, C. Cho W, Kobarfard F, Rajabi S, Martorell M, Kumar P, Martins N, Subhra Santra T, Sharifi-Rad J. Liposomal Cytarabine as Cancer Therapy: From Chemistry to Medicine

Cancer is the second leading cause of death worldwide. The main modality to fight against cancer is surgery, radiotherapy, and chemotherapy, and more recently targeted therapy, gene therapy and immunotherapy, which play important roles in treating cancer patients. In the last decades, chemotherapy has been well developed. Nonetheless, administration of the drug is not always successful, as limited drug dosage can reach the tumor cells.. In this context, the possibility to use an encapsulated anti-cancer drug may potentially solve the problem. Liposomal cytarabine is a formulation with pronounced effectiveness in lymphomatous meningitis and reduced cardiotoxicity if compared to liposomal anthracyclines. Thus, the future liposomal cytarabine use could be extended to other diseases given its reduction in cytotoxic side effects compared to the free formulation. This review summarizes the chemistry and biology of liposomal cytarabine, with exploration of its clinical implications.

Prevention of Opioid Abuse and Treatment of Opioid Addiction: Current Status and Future Possibilities

Prescription opioid medications have seen a dramatic rise in misuse and abuse, leading regulators and scientists to develop policies and abuse-deterrent technologies to combat the current opioid epidemic. These abuse-deterrent formulations (ADFs) are intended to deter physical and chemical tampering of opioid-based products, while still providing safe and effective delivery for therapeutic purposes. Even though formulations with varying abuse-deterrent technologies have been approved, questions remain about their effectiveness. While these formulations provide a single means to combat the epidemic, a greater emphasis should be placed on formulations for treatment of addiction and overdose to help those struggling with opioid dependence. This article analyzes various ADFs currently in clinical use and explores potential novel systems for treatment of addiction and prevention of overdose.

Liposomal Bupivacaine Versus Standard Periarticular Injection in Total Knee Arthroplasty With Regional Anesthesia: A Prospective Randomized Controlled Trial

BACKGROUND

Liposomal bupivacaine (Exparel) is a long-acting local anesthetic preparation with demonstrated efficacy over placebo in reducing postoperative pain and opioid requirement. Limited comparative efficacy and cost-effectiveness data exist for its use in total knee arthroplasty (TKA) when used in a multimodal, opioid-sparing analgesic and anesthetic approach. We hypothesized that liposomal bupivacaine offers no clinical advantage over our standard of care but carries significant economic impact.

METHODS

This is a prospective, randomized, single-blinded, controlled trial comparing liposomal bupivacaine periarticular injection (PAI) to our current approach including conventional bupivacaine PAI, in the setting of regional anesthesia. All adult unilateral TKA patients of the collaborating surgeon were eligible to participate in the study. Patients were randomized 1:1 to either the liposomal bupivacaine protocol or the standard-of-care protocol. All patients received regional anesthesia and standard postoperative analgesia protocols. Patients and all postoperative healthcare providers were blinded to study arm assignment.

RESULTS

A total of 59 patients were enrolled per our a priori power calculation after 1 exclusion for randomization error. No significant demographic differences between the study arms were found. There was no statistically significant difference in the primary outcome of number of physical therapy (PT) sessions required to achieve home-going discharge goals (3.0 ± 1.2 vs 3.6 ± 1.3, P = .137), nor in the clinical secondary outcomes. A significant difference in medication charges was found.

CONCLUSION

Our study supports earlier literature suggesting no significant clinical benefit of using liposomal bupivacaine over standard of care in TKA and underscores cost-of-care concerns with this agent.

EMMEZ H, ULUDAĞ O, BAL NB, DEĞİM T. Antinociceptive Effect of Liposomal Bupivacaine Formulations After Intrathecal Administration in Rats

Background/aim

Based on our previous in vitro study with multilamellar liposomal bupivacaine (MLB) versus bupivacaine alone in artificial cerebrospinal fluid, we aimed to investigate in vivo antinociceptive effect of intrathecal MLB by determining tail flick latency (TFL) time after thermal stimulation in rats.

Materials and methods

After preparing MLB and high-yield drug entrapment in liposome (HYDEL) bupivacaine, 18 female Wistar rats were assigned to 3 groups as control (bupivacaine) and study groups (MLB and HYDEL bupivacaine) including 6 rats in each group to administer these drugs intrathecally. Antinociceptive activity was determined in terms of TFL time after thermal stimulation. Maximum possible effect (MPE) calculated from TFL times and rats with motor block were documented.

Results

TFL times after intrathecal injection of HYDEL bupivacaine were significantly longer than that of the control and MLB groups (P < 0.05) and returned to baseline 180 min after intrathecal injection. MPE (100%) with intrathecal HYDEL bupivacaine occurred between 10 to 45 min. Afterwards, MPEs were 70% and 50% for the control and MLB groups, respectively. Motor block disappeared after 20 min in the study groups while it lasted 75 min in the control.

Conclusion

Intrathecal administration of MLB and HYDEL bupivacaine in rats resulted in longer duration of antinociceptive activity with shorter motor block duration.

The synthesis and application of nano doxorubicin- indocyanine green matrix metalloproteinase-responsive hydrogel in chemophototherapy for head and neck squamous cell carcinoma

Background

Head and neck squamous cell carcinoma (HNSCC) is one of the most common malignancies, with high rates of mortality and morbidity worldwide. Owing to the special anatomical location of this tumor, an effective, minimally invasive treatment with low systemic toxicity is highly desirable. Hydrogels have shown great potential for tumor-targeting therapy, with excellent performance. However, there have been few reports on co-loading photosensitizers and chemotherapeutic drugs into hydrogels. In this study, we synthesized a nano doxorubicin-indocyanine green matrix metalloproteinase (MMP)-responsive hydrogel (denoted as NDIMH), combining chemotherapy and phototherapy, to achieve superior antitumor efficacy.

Methods

First, NDIMH was synthesized and characterized by scanning electron microscopy and drug-release assays. Second, the photosensitivity properties and antitumor efficiency of this drug delivery system were studied in vivo and in vitro. Last, the imaging and biodistribution of NDIMH were monitored using the Maestro EX in vivo imaging system.

Results

The nanodrugs loaded into the smart hydrogel exhibited uniform size distribution, excellent size stability, and a sustained release in the presence of MMP-2. NDIMH showed ideal photosensitivity characteristics under light. NDIMH with 808 nm near-infrared (NIR) irradiation effectively inhibited the viability, invasion, and metastasis of SCC-15 in vitro. After intratumoral injection of NDIMH with 808 nm NIR illumination, the hydrogels exhibited favorable synergistic antitumor efficacy and acceptable biosafety. Additionally, fluorescence imaging showed that NDIMH could significantly improve the retention of nanodrugs at the tumor site.

Conclusion

The intratumoral injection of NDIMH with 808 nm NIR irradiation could be a promising chemophototherapy alternative for HNSCC.

Vesicular phospholipid gels as drug delivery systems for small molecular weight drugs, peptides and proteins: State of the art review

Lipid-based drug delivery has been investigated for a long time when it comes to liposomes and solid-lipid implants or solid-lipid nanoparticles. The promising, characteristic properties of these systems have led to the development of newer lipid-based drug delivery systems for the sustained release of drugs like liposomes for sustained delivery of substances, DepoFoam™ technology, phospholipid-based phase separation gels and vesicular phospholipid gels. Vesicular phospholipid gels (VPGs) are highly concentrated, viscous dispersions of high amounts of phospholipids in aqueous drug solution. The easy, solvent-free manufacturing process, high biocompatibility and various applications, as depot formulation for the sustained delivery of drugs and as a storage form of small unilamellar vesicles make VPGs highly attractive as drug carriers. Over the last years, the solvent free preparation process has advanced from high pressure homogenization to dual centrifugation (DC). Thereby a very simple one step process has been established for the preparation of VPGs. The semisolid VPG was first described in 1997 by Brandl et al. Since then, many formulations have been developed, encapsulating small molecular weight drugs like 5-FU (2003), cetrorelix (2005), cytarabine (2012) and exenatide (2015). In 2010, the first pharmaceutical protein, erythropoietin, was encapsulated in VPGs and sustained release of the substance was shown in vitro. In 2015, G-CSF was encapsulated in VPGs and tested in vivo for rotator cuff repair in a rat model and for PEGylated IFN-β-1b sustained release from vesicular phospholipid gels was demonstrated in vitro. Further, a very elegant administration technique for VPGs via needle-free injection was established. However this promising drug delivery system does still leave space for improvement and optimization. This review summarizes information about lipid-based depot systems in general and focuses on the historical development of VPGs. It emphasizes the advantages and drawbacks of VPGs as drug delivery device. Additionally, novel preparation methods and applications of VPGs will be discussed. A focus will be set on delivery of pharmaceutical proteins and peptides.

Probing the mechanism of bupivacaine drug release from multivesicular liposomes

The mechanism of drug release from complex dosage forms, such as multivesicular liposomes (MVLs), is complex and oftentimes sensitive to the release environment. This challenges the design and development of an appropriate in vitro release test (IVRT) method. In this study, a commercial bupivacaine MVL product was selected as a model product and an IVRT method was developed using a modified USP 2 apparatus in conjunction with reverse-dialysis membranes. This setup allowed the use of in situ UV-Vis probes to continuously monitor the drug concentration during release. In comparison to the traditional sample-and-separate methods, the new method allowed for better control of the release conditions allowing for study of the drug release mechanism. Bupivacaine (BPV) MVLs exhibited distinct tri-phasic release characteristics comprising of an initial burst release, lag phase and a secondary release. Temperature, pH, agitation speed and release media composition were observed to impact the mechanism and rate of BPV release from MVLs. The size and morphology of the MVLs as well as their inner vesicle compartments were analyzed using cryogenic-scanning electron microscopy (cryo-SEM), confocal laser scanning microscopy and laser diffraction, where the mean diameters of the MVLs and their inner "polyhedral" vesicles were found to be 23.6 ± 11.5 μm and 1.52 ± 0.44 μm, respectively. Cryo-SEM results further showed a decrease in particle size and loss of internal "polyhedral" structure of the MVLs over the duration of release, indicating erosion and rearrangement of the lipid layers. Based on these results a potential MVL drug release mechanism was proposed, which may assist with the future development of more biorelevant IVRT method for similar formulations.

Preparation of giant lipid vesicles with controllable sizes by a modified hydrophilic polydimethylsiloxane microarray chip

This paper presents an accessible method to prepare giant lipid vesicles (GLVs) with controllable sizes based on the quick formation of patterned lipid films. Lipid solutions naturally penetrate into arrayed micro-apertures on a modified hydrophilic Polydimethylsiloxane (PDMS) chip, and excess lipid films on the surface are removed by a glass slide. Three main factors, the depth and diameter of the micro-apertures and concentration of the lipid solution, were investigated to obtain an optimal preparation condition. Based on this condition, the formed GLVs have a controllable size and narrow size distribution (the standard deviation < 5 μm). By controlling the diameter of the micro-aperture and concentration of the lipid solution, GLVs with various sizes (23, 48, 66 and 82 μm) can be formed.

Injectable nanocomposite analgesic delivery system for musculoskeletal pain management

Musculoskeletal pain is a major health issue which results from surgical procedures (i.e. total knee and/or hip replacements and rotator cuff repairs), as well as from non-surgical conditions (i.e. sympathetically-mediated pain syndrome and occipital neuralgia). Local anesthetics, opioids or corticosteroids are currently used for the pain management of musculoskeletal conditions. Even though local anesthetics are highly preferred, the need for multiple administration presents significant disadvantages. Development of unique delivery systems that can deliver local anesthetics at the injection site for prolonged time could significantly enhance the therapeutic efficacy and patient comfort. The goal of the present study is to evaluate the efficacy of an injectable local anesthetic nanocomposite carrier to provide sustained analgesic effect. The nanocomposite carrier was developed by encapsulating ropivacaine, a local anesthetic, in lipid nanocapsules (LNC-Rop), and incorporating the nanocapsules in enzymatically crosslinked glycol chitosan (0.3GC) hydrogels. Cryo Scanning Electron Microscopic (Cryo SEM) images showed the ability to distribute the LNCs within the hydrogel without adversely affecting their morphology. The study demonstrated the feasibility to achieve sustained release of lipophilic molecules from the nanocomposite carrier in vitro and in vivo. A rat chronic constriction injury (CCI) pain model was used to evaluate the efficacy of the nanocomposite carrier using thermal paw withdrawal latency (TWL). The nanocomposite carriers loaded with ropivacaine and dexamethasone showed significant improvement in pain response compared to the control groups for at least 7 days. The study demonstrated the clinical potential of these nanocomposite carriers for post-operative and neuropathic pain.

STATEMENT OF SIGNIFICANCE

Acute or chronic pain associated with musculoskeletal conditions is considered a major health issue, with healthcare costs totaling several billion dollars. The opioid crisis presents a pressing clinical need to develop alternative and effective approaches to treat musculoskeletal pain. The goal of this study was to develop a long-acting injectable anesthetic formulation which can sustain a local anesthetic effect for a prolonged time. This in turn could increase the quality of life and rehabilitation outcome of patients, and decrease opioid consumption. The developed injectable nanocomposite demonstrated the feasibility to achieve prolonged pain relief in a rat chronic constriction injury (CCI) model.

An overview on the current status of cancer nanomedicines

PURPOSE

Cancer remains a significant cause of morbidity and mortality across the globe. A recent report suggests around 14.1 million new cases and 8.2 million cancer-related deaths, which are expected to reach 21.7 million and 13 million by 2030 worldwide, respectively.

MATERIALS AND METHODS

Because of highly complex mechanisms of cancer progression, it is important to explore and develop new innovative technologies which are more efficient compared with presently available treatment options.

RESULTS

Currently, chemotherapy, radiation and surgery are the most commonly used cancer treatment methods. In the last decade, nanomedicine emerged as an alternative treatment option that uses specific drug-delivery systems, improves efficacy of drugs and reduces detrimental side effects to normal tissues.

CONCLUSION

In this review, we have summarized cancer nanomedicines (active and passive drug delivery) available in the market. We have also discussed other nanomedicines that are at different stages of clinical trials.

Functional aqueous droplet networks

Droplet interface bilayers (DIBs), comprising individual lipid bilayers between pairs of aqueous droplets in an oil, are proving to be a useful tool for studying membrane proteins. Recently, attention has turned to the elaboration of networks of aqueous droplets, connected through functionalized interface bilayers, with collective properties unachievable in droplet pairs. Small 2D collections of droplets have been formed into soft biodevices, which can act as electronic components, light-sensors and batteries. A substantial breakthrough has been the development of a droplet printer, which can create patterned 3D droplet networks of hundreds to thousands of connected droplets. The 3D networks can change shape, or carry electrical signals through defined pathways, or express proteins in response to patterned illumination. We envisage using functional 3D droplet networks as autonomous synthetic tissues or coupling them with cells to repair or enhance the properties of living tissues.

The Effects of Body Mass Index on Pain Control With Liposomal Bupivacaine in Hip and Knee Arthroplasty

BACKGROUND

There is evidence to suggest that liposomal bupivacaine (LB) is an effective component of a multimodal pain regimen for total joint arthroplasty (TJA). Obesity has been associated with chronic pain following TJA. This study assessed whether early postoperative pain is affected by body mass index (BMI), and whether the standard LB dose has similar effects on obese vs nonobese patients.

METHODS

A retrospective analysis of 2629 primary TJA over a 12-month period was conducted, with LB used in half of this group. Patients were further classified as nonobese (BMI < 30) or obese (BMI ≥ 30). Pain scores and narcotic use were recorded. Independent-sample t-tests were used for continuous variables and chi-squared analyses for categorical variables. A multivariate regression analysis was performed.

RESULTS

Significantly less narcotic was required on postoperative days (POD) 0 and 1 in patients receiving LB compared to those who did not in both obese and nonobese patient groups. On POD 2, obese and nonobese patients had an increase in narcotic requirement, which was significant in obese patients. A regression analysis found that on POD 0 and POD 1, lack of LB use, obesity, and younger age were independently associated with increased narcotic use.

CONCLUSION

While narcotic requirement of obese and nonobese patients decreased on POD 0 and POD 1 with initiation of LB at our institution, all patients demonstrated increased narcotic requirement on POD 2 which was statistically and clinically significant in obese patients. Further studies are needed to determine the optimal pain regimen in the growing obese population undergoing TJA.

Study on the in situ aggregation of liposomes with negatively charged phospholipids for use as injectable depot formulation

Compared to conventional parenteral formulations injectable depot formulations, owing to a sustained drug release, offer several advantages, such as a reduced dosing frequency - and consequent improved compliance - or a predictable release profile. Additionally, fluctuations in the drug blood level may be smoothened and consequently side effects reduced. Because of their capability to encapsulate water soluble drugs and their very low toxicity profile liposomes comprising phospholipids, most certainly represent a vehicle of choice for subcutaneous (s.c.) or intramuscular (i.m.) administration typical for depot injections too. In the past, especially liposomes containing negatively charged phosphatidylserines were investigated regarding their aggregation and fusion behavior upon addition of calcium ions. Liposomes need to have a large size to prevent fast removal from the s.c. or i.m. injection site to make them useful as depot vehicle. In order to obtain such large liposomes, aggregation of smaller liposomes may be considered. Aim of the present study was to induce and investigate controlled aggregation of vesicles containing other negatively charged phospholipids besides phosphatidylserines upon mixing with a solution of divalent cations. L-α-phosphatidylcholine from egg (EPC) liposomes formulated with 25 mol% of 1,2-dipalmitoyl-sn-glycero-3-phosphate (DPPA) or 1,2-distearoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DSPG) proved to be possible lipid-based depot candidates due to their strong aggregation induced by calcium and magnesium cations. Different aggregation profiles with both cations could be observed. Morphological investigations of the aggregates showed that individual liposomes remain stable in the aggregates and no fusion occurred. A fluorescence-based fusion assay confirmed these results. Differential scanning calorimetry measurements supported the findings of the diverse aggregation profiles with calcium or magnesium owing to different binding sites of the cations to the lipid molecules.