Liposome Suspensions Research Articles

Design of an oral formulation combining PVA nanofibers and PEGylated liposomes for enhanced drug delivery

Modifying the surface properties of nanoparticles is crucial for enhancing the oral absorption of encapsulated drugs. Although both mucoadhesion and mucus permeability are essential properties for improving oral absorption, their opposing characteristics render their combination in a single formulation challenging. The present study aimed to integrate both strategies and design a novel oral formulation by creating nanofibers from a mucoadhesive polymer solution containing approximately 100 nm PEGylated liposomes. First, we evaluated the physicochemical properties of PEGylated liposomes released from nanofibers made of sodium carboxymethylcellulose (CMC-Na) and polyvinyl alcohol (PVA), as well as from PVA alone nanofibers. Liposomes released from CMC-Na/PVA nanofibers had a particle size of 533.9 ± 85.0 nm, showing aggregation, while those from PVA nanofibers maintained a particle size without aggregation (142.8 ± 7.31 nm). To increase the liposome content in PVA nanofibers, we used hydroxypropyl-β-cyclodextrin (HPβCD) as a cryoprotectant, converting the suspension to powder and increasing liposome content by approximately 30-fold. PVA nanofibers increasing liposome content had a fiber diameter of 355.5 ± 77.1 nm, and liposomes released from nanofibers retained their morphology. We then used the flow-through method to evaluate the formulation's adhesive properties, and our findings confirmed its better mucosal adhesion and reduced excretion by mucus clearance (about 1/10) compared to a liposome suspension. Subsequent application to rat intestinal tissue showed that the mucus partially dissolved the nanofibers, allowing PEGylated liposomes to penetrate the mucus layer. Oral administration to rats showed improved gastrointestinal retention, thereby confirming that this novel oral formulation may improve drug oral absorption.

The Effect of Different Surfactants and Polyelectrolytes on Nano-Vesiculation of Artificial and Cellular Membranes.

Nano- and micro-sized vesicular and colloidal structures mediate cell-cell communication. They are important players in the physiology of plants, animals, and humans, and are a subject of increasing interest. We investigated the effect of three surfactants, N-cetylpyridinium chloride (CPC), sodium dodecyl sulfate (SDS), and Triton X-100 (TX100), and two anionic polyelectrolytes, sodium polystyrene sulfonate (NaPSS) and sodium polymethacrylate (NaPMA), on nanoliposomes. In addition, the effect of SDS and TX100 on selected biological membranes (erythrocytes and microalgae) was investigated. The liposomes were produced by extrusion and evaluated by microcalorimetry and light scattering, based on the total intensity of the scattered light (Itot), hydrodynamic radius (Rh), radius of gyration (Rg), shape parameter p (=Rh/Rg,0), and polydispersity index. The EPs shed from erythrocytes and microalgae Dunaliella tertiolecta and Phaeodactylum tricornutum were visualized by scanning electron microscopy (SEM) and analyzed by flow cytometry (FCM). The Rh and Itot values in POPC liposome suspensions with added CPC, SDS, and TX100 were roughly constant up to the respective critical micelle concentrations (CMCs) of the surfactants. At higher compound concentrations, Itot dropped towards zero, whereas Rh increased to values higher than in pure POPC suspensions (Rh ≈ 60-70 nm), indicating the disintegration of liposomes and formation of larger particles, i.e., various POPC-S aggregates. Nanoliposomes were stable upon the addition of NaPSS and NaPMA, as indicated by the constant Rh and Itot values. The interaction of CPC, SDS, or TX100 with liposomes was exothermic, while there were no measurable heat effects with NaPSS or NaPMA. The SDS and TX100 increased the number density of EPs several-fold in erythrocyte suspensions and up to 30-fold in the conditioned media of Dunaliella tertiolecta at the expense of the number density of cells, which decreased to less than 5% in erythrocytes and several-fold in Dunaliella tertiolecta. The SDS and TX100 did not affect the number density of the microalgae Phaeodactylum tricornutum, while the number density of EPs was lower in the conditioned media than in the control, but increased several-fold in a concentration-dependent manner. Our results indicate that amphiphilic molecules need to be organized in nanosized particles to match the local curvature of the membrane for facilitated uptake. To pursue this hypothesis, other surfactants and biological membranes should be studied in the future for more general conclusions.

Intranasal Administration of Bedaquiline-Loaded Fucosylated Liposomes Provides Anti-Tubercular Activity while Reducing the Potential for Systemic Side Effects.

Liposomal formulations of antibiotics for inhalation offer the potential for the delivery of high drug doses, controlled drug release kinetics in the lung, and an excellent safety profile. In this study, we evaluated the in vivo performance of a liposomal formulation for the poorly soluble, antituberculosis agent, bedaquiline. Bedaquiline was encapsulated within monodisperse liposomes of ∼70 nm at a relatively high drug concentration (∼3.6 mg/mL). Formulations with or without fucose residues, which bind to C-type lectin receptors and mediate a preferential binding to macrophage mannose receptor, were prepared, and efficacy was assessed in an in vivo C3HeB/FeJ mouse model of tuberculosis infection (H37Rv strain). Seven intranasal instillations of 5 mg/kg bedaquiline formulations administered every second day resulted in a significant reduction in lung burden (∼0.4-0.6 Δlog10 CFU), although no differences between fucosylated and nonfucosylated formulations were observed. A pharmacokinetic study in healthy, noninfected Balb/c mice demonstrated that intranasal administration of a single dose of 2.5 mg/kg bedaquiline liposomal formulation (fucosylated) improved the lung bioavailability 6-fold compared to intravenous administration of the same formulation at the same dose. Importantly, intranasal administration reduced systemic concentrations of the primary metabolite, N-desmethyl-bedaquiline (M2), compared with both intravenous and oral administration. This is a clinically relevant finding as the M2 metabolite is associated with a higher risk of QT-prolongation in predisposed patients. The results clearly demonstrate that a bedaquiline liposomal inhalation suspension may show enhanced antitubercular activity in the lung while reducing systemic side effects, thus meriting further nonclinical investigation.

Pharmacokinetics of Extended-release Buprenorphine and Clinical Efficacy for Postoperative Pain Management in the Domestic Ferret (Mustela putorius furo).

Buprenorphine hydrochloride (Bup-HCl) is a common injectable opioid analgesic. In ferrets, Bup-HCl must be administered every 8 to 12 h to maintain clinical efficacy. Extended-release analgesics offer multiple advantages, including reduced handling and injection frequency, improved compliance, and increased protection from end-of-dose failure. Although efficacy of extended-release buprenorphine formulations has been demonstrated in other species, their use in the domestic ferret has not been investigated. In this study, we evaluated the pharmacokinetics of a compounded polymeric formulation of buprenorphine (Bup-ER) and a pharmaceutical-grade, FDA-indexed liposomal suspension (Bup-XR). Two doses each of Bup-ER (0.12 and 0.2 mg/kg) and Bup-XR (0.2 and 0.6 mg/kg SC) were administered to young adult female ferrets and plasma concentrations were measured between 0 and 96 h (n = 4 animals per timepoint). All doses of both drugs achieved therapeutic plasma levels by 30 min. Furthermore, high-dose Bup-XR maintained therapeutic levels for 72 h, followed by high-dose Bup-ER (less than 48 h), low-dose Bup-XR (24 h), and low-dose Bup-ER (less than 24 h). In this study, we also developed a pain scoring system and utilized this to compare analgesic efficacy between single high-dose Bup-XR (0.6 mg/kg SC) and a standard postoperative course of Bup-HCl (0.02 mg/kg SC every 10 to 12 h for 8 doses) after ovariohysterectomy. Ferrets receiving Bup-XR had significantly lower respiratory rate and posture scores in the first 24 h postoperatively than did those that received Bup-HCl and were less likely to react to palpation of the surgical incision. Of note, ferrets that received high-dose Bup-ER had a significantly higher incidence of injection site reactions than ferrets that received Bup-HCl (P = 0.0137). This study demonstrates that a single dose of Bup-XR (0.6 mg/kg SC) is a safe and effective analgesic in female ferrets, with a duration of action up to 72 h and minimal side effects, offering a refinement to analgesia in this species.

Physical Properties of Cellulose Derivative-Based Edible Films Elaborated with Liposomes Encapsulating Grape Seed Tannins.

Combined use of edible films (EF) with nanoencapsulation systems could be an effective alternative for improving the films' physical properties and maintaining bioactive compounds' stability. This research work focuses on the combined use of EF of cellulose-derived biopolymers enriched with liposomes that encapsulate grape seed tannins and on the subsequent evaluation of the physical properties and wettability. Tannin-containing liposomal suspensions (TLS) showed 570.8 ± 6.0 nm particle size and 99% encapsulation efficiency. In vitro studies showed that the release of tannins from liposomes was slower than that of free tannins, reaching a maximum release of catechin of 0.13 ± 0.01%, epicatechin of 0.57 ± 0.01%, and gallic acid of 3.90 ± 0.001% over a 144 h period. Adding liposomes to biopolymer matrices resulted in significant decrease (p < 0.05) of density, surface tension, tensile strength, elongation percentage, and elastic modulus in comparison to the control, obtaining films with greater flexibility and lower breaking strength. Incorporating TLS into EF formulations resulted in partially wetting the hydrophobic surface, reducing adhesion and cohesion compared to EF without liposomes. Results indicate that the presence of liposomes improves films' physical and wettability properties, causing them to extend and not contract when applied to hydrophobic food surfaces.

Design, Optimization, and Characterization of Zolmitriptan Loaded Liposomal Gels for Intranasal delivery for acute migraine therapy

Zolmitriptan is the primary drug for the treatment of Migraine. However, the bioavailability of the drug is low and requires repetitive administration leading to side effects. Zolmitriptan's bioavailability can be improved by incorporating it into liposomes as a topical intranasal gel. The formulation was developed using a Central composite design employing a response surface approach. The new formulations were tested for particle size, shape, drug entrapment efficiency, and in vitro drug release. Permeation experiments and histopathology in rats were also conducted to determine the formulation's safety. The vesicle size was found to be in the range of 103.82±7.16 to 694.38±1.02 nm, zeta potential --19.28 to -32.8 mV, Entrapment Efficiency from 55.49±1.37 to 99.12±0.36 %, and cumulative drug release from 59.71±6.94 to 99.38±0.13 % respectively. In-vitro drug release of G1 and G3 gel formulations showed a non-Fickian released pattern during the studies. A comparison of the permeation coefficient of G1 (0.539 μg/cm2) and G3 (5.3 μg/cm2) showed a slight variation in the drug release rate after 24 hrs. For the liposomal gel and its solution, we found a significant difference in drug penetration of p0.05 after 12 hours compared to the control gel. There were substantial differences in bioavailability and pharmacokinetics between the optimal Liposomal Gel Formulation and other formulations, including the drug solution, liposomal suspension, and optimized formulation F12. The liposomal gel is non-irritating and safe for topical administration by histopathological investigations. Therefore, the study demonstrated that Zolmitriptan Liposomal gel has better efficacy, good tolerability, and enhanced bioavailability, making it an optimal treatment for acute Migraine.

Effect of ultrasound exposure time in the size distribution of lecithin liposomes in the nanoscale

Abstract The characteristics of liposome suspensions subjected to ultrasound were studied using the Nanoparticle Trajectory Analysis (NTA) technique. These were prepared with either DPPC or soy lecithin using the thin layer method. For each preparation protocol, the size and ζ potential probability densities were determined by averaging the densities obtained in several measurements. Ultrasound exposure changed the characteristics of the size and ζ potential distributions. For the size distribution, the exposure resulted in an increment of the number of liposomes with diameters in the range of ∼ 100 nm, the corresponding size distributions became slimmer, with mean diameters smaller than the ones without exposure. This is reflected in the reduction of the polydispersity index experienced by the liposome suspensions after sonication. For DPPC liposomes, it changed from ≈ 0.26 without exposure to ≈ 0.19 after 10 min sonication whereas for soy lecithin liposomes it changed from ≈ 0.30 without exposure to ≈ 0.21 after 10 min sonication. For the ζ potential, after 10 min exposure, the distributions became wider, with mean values more negative than the ones without exposure. The mean ζ potential, for DPPC liposomes, changed from ≈ −35 mV without exposure to ≈ −39 mV after 10 min sonication whereas for soy lecithin liposomes it changed from ≈ −38 mV without exposure to ≈ −42 mV after 10 min sonication. Therefore, our results show that exposure to ultrasound reduced the polydispersity and increased the stability of the liposome suspensions.

Liposomes bearing poly(hydroxyethyl acrylate-co-ethyl vinyl sulfide) and indocyanine green and their temperature, oxidation, and near infrared-responsive release property

Liposomes are widely used for smart delivery due to their biodegradability and biocompatibility. Recently, liposomes have been developed to respond to dual and multi-stimuli. This development leads to the potential for superior in vitro and in vivo drug delivery in the future. In this study, egg PC liposomes responsive to temperature, oxidation, and NIR irradiation were prepared by modifying the liposomal membranes with poly(hydroxyethyl acrylate-co-ethyl vinyl sulfide) (P(HEA-co-EVS)) and including indocyanine green (ICG) in the liposomes.The copolymer was found to exhibit a lower critical solution temperature (LCST) and it was oxidizable and surface-active.On the TEM photos of the liposomes, multi-lamellar vesicles were found and the size was in accordance with the hydrodynamic diameter. The liposomes released their payload in response to H2O2 concentration possibly because the EVS was oxidized by the oxidizing agent. The liposome exhibited a temperature-responsive release possibly due to the thermal contraction of the copolymer chains.In addition, the release was triggered when a near-infrared(NIR) laser was irradiated to the liposome suspensions. Under NIR irradiation, the photosensitizer (i.e. ICG) can generate heat and reactive oxygen species, which, in turn, would induce the conformational and polarity change of the polymer chains, leading to a release.

Photobiomodulation therapy using a class 3b laser does not cause premature rupture of multivesicular liposomal bupivacaine suspensions in a cadaver model.

To determine if photobiomodulation causes a premature release of liposomal bupivacaine (LB) suspensions. A 25-kg mixed breed dog cadaver euthanized for reasons unrelated to this study. In September 2022, a proximomedial tibial incision was made in a dog cadaver, and a tibial plateau leveling osteotomy plate was implanted. A stab incision was made one-half inch distal to the incision, and a tunnel to the plate was created prior to closure of the primary wound. A 3-cc anal sac catheter was advanced through the distal incision until the bulb rested against the face of the plate. Seven treatment groups of treatment power (watts) and total energy (joules/cm2) were defined as: A, 0.5 W, 2.0 J/cm2; B, 0.5 W, 4.0 J/cm2; C, 0.5 W, 6.0 J/cm2; D, 1.0 W, 2.0 J/cm2; E, 1.0 W, 4.0 J/cm2; F, 1.0 W, 6.0 J/cm2; and sham, 0.0 W, 0.0 J/cm2. Ten samples per group of 2 mL of LB were infused into a new catheter and treated percutaneously with a class 3b laser. All samples remained in the catheter for 12 seconds to reflect the longest treatment time. Post-treatment free bupivacaine concentrations were identified with high-performance liquid chromatography. The median free bupivacaine concentration was reported as: sham, 1.89 mg/mL; A, 1.93 mg/mL; B, 2.01 mg/mL; C, 2.05 mg/mL; D, 1.92 mg/mL; E, 2.03 mg/mL; and F, 2.00 mg/mL. There were no differences in median free bupivacaine concentrations between groups (P = .988). Concurrent LB and photobiomodulation are recommended during the postoperative period. The results of this proof-of-concept study suggest that concurrent use of LB and photobiomodulation may be safe, but in vivo studies at similar and stronger photobiomodulation settings are warranted.

Average dose rate is the primary determinant of lipid peroxidation in liposome membranes exposed to pulsed electron FLASH beam

BackgroundLipid peroxidation, a self-propagating chain reaction that oxydates lipid molecules, contributes to harmful effects of ionizing radiation. A decrease in peroxidation at higher dose rates could play a role in the FLASH sparing effect. PurposeWe explored how lipid peroxidation induced by FLASH (>100 Gy/s) and conventional (CONV, <0.2 Gy/s) radiation depends on lipid concentration and content of polyunsaturated fatty acids (PUFA). Additionally, we investigated the correlation between the lipid peroxidation and the main beam parameters characterizing pulsed electron beams, namely the dose per pulse (DRp) and the average dose rate (DRav). MethodsWe employed phosphatidylcholine (PC) liposomes as a model of biological membranes. Suspensions of liposomes containing different proportions of linoleic acid (LA) were prepared at various concentrations and irradiated at FLASH and CONV dose rates. Additionally, the liposomes were exposed to beams characterized by diverse combinations of DRp and DRav. The extent of lipid peroxidation was assessed by monitoring oxygen consumption (ΔpO2) and measuring the yield of malondialdehyde (MDA), and in certain instances, of lipid peroxides (LOOH). ResultsRegardless of the radiation dose, liposome concentration or LA content, ΔpO2 and the yield of MDA were significantly lower for FLASH than for CONV irradiation. Increase in the proportion of readily oxidizable LA in the lipid had negative effect on the MDA yield but correlated positively with ΔpO2 and LOOH yield. Exposing liposomes to beams operating at different pulse repetition frequencies, while keeping the total dose and DRp constant, resulted in markedly different ΔpO2 and MDA yields. In contrast, DRav was found to exhibit stable correlation with both MDA yield and ΔpO2. ConclusionsIrradiation at FLASH dose rates produces lower yield of lipid peroxidation in PUFA-containing artificial PC membranes than CONV irradiation under all tested conditions. Time-averaged dose rate, in contrast to pulse dose rate, was the critical parameter determining the level of lipid peroxidation induced by pulsed electron beams.

Does a liposomal bupivacaine suspension (Nocita®) provide extended pain mitigation when disbudding dairy calves?

The goal of this study was to explore a liposomal bupivacaine suspension product (Nocita®) (LB) as a local anesthetic for calf disbudding relative to bupivacaine (B) and a lidocaine control (C). We hypothesized that LB would provide extended pain miti­gation relative to B and C.

Synthesis of cationic liposome nanoparticles using a thin film dispersed hydration and extrusion method.

Liposome nanoparticles can carry a wide range of therapeutic molecules including small molecules and nucleic acid-based therapeutics. Potential benefits include translocation across physiological barriers, reduced systemic toxicity, and enhanced pharmacokinetic parameters such as absorption, distribution, selective release and optimal elimination kinetics. Liposome nanoparticles can be generated with a wide range of natural and synthetic lipid-based molecules that confer desirable properties depending on the desired therapeutic application Nel et al (2023), Large (2021), Elkhoury (2020). This protocol article seeks to detail the procedures involved in the production of cationic liposomes using thin-film dispersed hydration method with an estimated uniform size of 60-70 nm for targeted drug administration in tumor cells, by modifying the previous one also published by the same authors cited here. The method was carrying out using N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methyl (DOTAP, 2 mg) as cationic lipid and cholesterol (0.5 mg) in a molar ratio of 7:3 respectively. The liposomal suspension was obtained and its physical, chemical and biological properties were determined. A two-step extrusion process, using 100 nm and 50 nm polycarbonate membranes, was carried. The results demonstrate generation of liposome nanoparticles with a size of 60-70 nm stable for at least 16 weeks and with an encapsulation efficiency of approximately 81% using Doxorubicin.

Fucoidan coated liposomes loaded with novel antituberculosis agent: preparation, evaluation, and cytotoxicity study

In this article, we described a novel antituberculosis imidazotetrazine derivative designed in fucoidan-coated liposomes to reduce its cytotoxicity and investigate its mucoadhesive properties. Firstly, fucoidan extracted from Ascophyllum nodosum was used for additional stabilization of liposomal suspensions and to give it mucoadhesive properties. PEG-600 and/or Tween-80 were used to increase the shelf life of liposomal suspension. The ratio of the fucoidan: lipids 1:2 was found to be the optimum that produces stable fucoidan-coated liposomes. The particle size of the optimum formulation was 336.3 ± 5.4, the PDI was 0.33, and the zeta potential was −39.6. This size and the practical spherical shape of the particles were confirmed by atomic force microscopy. In addition, the in vitro release profiles from uncoated and fucoidan-coated liposomes revealed significant and faster release compared to free antituberculosis agent. Using the MTT assay test, the fucoidan-coated liposomes exhibited fourteen times lower cytotoxicity (IC50 7.14 ± 0.91 µg/ml) than the free drug (IC50 0.49 ± 0.06). Moreover, the mucoadhesive capabilities of these liposomal formulations were also confirmed using snail mucin, which highlighting their potential use as an effective delivery system for antituberculosis therapy, with notable improvements in dissolution rate and reduced cytotoxicity.

Effect of DMSO on Structural Properties of DMPC and DPPC Liposome Suspensions.

The study and characterization of the biophysical properties of membranes and drug-membrane interactions represent a critical step in drug development, as biological membranes act as a barrier that the drug must overcome to reach its active site. Liposomes are widely used in drug delivery to circumvent the poor aqueous solubility of most drugs, improving systemic bioavailability and pharmacokinetics. Further, they can be targeted to deliver to specific disease sites, thus decreasing drug load, and reducing side effects and poor adherence to treatment. To improve drug solubility during liposome preparation, DMSO is the most widely used solvent. This raises concern about the potential effect of DMSO on membranes and leads us to investigate, using DSC and EPR, the influence of DMSO on the behavior of lipid model membranes of DMPC and DPPC. In addition, we tested the influence of DMSO on drug-membrane interaction, using compounds with different hydrophobicity and varying DMSO content, using the same experimental techniques. Overall, it was found that with up to 10% DMSO, changes in the bilayer fluidity or the thermotropic properties of the studied liposomes were not significant, within the experimental uncertainty. For higher concentrations of DMSO, there is a stabilization of both the gel and the rippled gel phases, and increased bilayer fluidity of DMPC and DPPC liposomes leading to an increase in membrane permeability.

Bupivacaine liposomal injectable suspension does not provide improved pain control in dogs undergoing abdominal surgery.

To evaluate the difference in postoperative pain scores of dogs undergoing abdominal surgery receiving surgical incision infiltration of saline or bupivacaine liposomal injectable suspension (BLIS). 40 dogs undergoing exploratory laparotomy. Dogs were prospectively enrolled and randomized to receive either BLIS or saline surgical incision infiltration. All dogs received 5.3 mg of BLIS/kg or an equal volume of saline infiltrated in the muscle/fascia, subcutaneous tissue, and intradermal layer during closure. All dogs received a standardized postoperative pain management protocol. Pain assessment was performed at select time points postoperatively by blinded observers with an electronic algometer, short version of the Glasgow Composite Measure Pain Scale (GCMPS), and indirect measures of pain, including systolic blood pressure, heart rate, and serum cortisol levels. At day 0, blood pressure was higher in the saline group (149.6 vs 125.8 mm Hg; P = .006). At day 3, GCMPS was lower in the BLIS group (BLIS = 1, saline = 2, P = .027), though both average GCMPS scores were low and only 10 dogs were available for day 3 assessments (6 BLIS and 4 saline). No other differences in algometer readings, GCMPS scores, other measured parameters, or need for rescue analgesia were present between BLIS and saline groups at any time point. There was no difference in postoperative incisional infection rate or complications. Use of BLIS for exploratory laparotomy did not provide improved pain control over postoperative opioid administration alone. Patients that received BLIS had no increase in short-term complications.

Liposomal Bupivacaine Suspension Can Reduce the Length of Stay of Patients Undergoing Open Reduction and Internal Fixation of Mandibular Fracture

Poorly controlled postoperative pain results in prolonged length of stay (LOS). The use of liposome bupivacaine injectable suspension (LB) for postoperative pain control is a relatively recent practice. The purpose of this study was to investigate the following. In patients undergoing open reduction and internal fixation of mandibular fracture(s), does the use of LB reduce LOS compared with regular bupivacaine? We implemented a retrospective cohort study of consecutive patients with mandibular fracture(s) presented to Grady Memorial Hospital in Atlanta, GA, from January 2021 to January 2022. Adult patients diagnosed with 1 or more isolated mandibular fracture(s) and treated by open reduction and internal fixation were included. We excluded patients with non-isolated mandibular fracture(s), isolated condyle, infected, previously treated fractures, and documented allergy to amide local anesthetics and/or its preservatives. Primary predictor variable was the use of local anesthetic. Primary outcome variable was LOS, defined as the number of days from surgical procedure until discharge. Secondary outcome variables were number of opioid prescription refill(s) and postoperative pain at discharge, determined with visual analogue score. Demographics, American Society of Anesthesiologists classification, smoking, alcohol exposure, illicit drug use, etiology, location, laterality, number of fracture(s), surgical approach, and method of maxillomandibular fixation. Univariate and bivariate analyses were calculated. Statistical significance was P<.05. Sixty-two subjects met the inclusion criteria (31 subjects in each group). The mean ages in LB/regular bupivacaine and regular bupivacaine alone groups were 33.3 (±12) and 35.1 (±15.6), respectively (P=.94), the mean LOS in days was 0.23 (±0.44) in LB/regular bupivacaine and 1.48 (±1.77) in regular bupivacaine alone (P=<.001), and the mean VAS pain scores for LB/regular bupivacaine and regular bupivacaine alone groups were 0.53 (±1.07) and 1.87 (±2.66), respectively (P=.02). Mean number of opioid prescription refill(s) was 0 in LB/regular bupivacaine and 1 in regular bupivacaine alone group, respectively (P=.01). The study findings suggest that the use of LB/regular bupivacaine for mandibular fracture(s) results in decrease in LOS and number of opioid refills compared to regular bupivacaine alone.

Single-Impact Electrochemistry of Redox Liposomes for the Detection of Virulence Factors

Early detection of pathogens is a key factor for the successful therapy of infectious diseases. Some of the pathogenic bacteria involved in diseases interact with the host by producing compounds that are toxic or disruptive to the cells. As these virulence factors can be easier to spot than the pathogen, strategies of detection can be focused on these released compounds to identify the pathogenic bacterium.[1] Liposomes are vesicles composed of a lipid bilayer membrane, and as such are often used to mimic living cells. Here, the strategy consists in making redox liposomes by encapsulating an electroactive probe in their inner cavity, which will be detected at the electrode.[2] Virulence factors interacting with the vesicles increase the permeability of the lipid membrane and the contents of the liposomes are released over time. This redox probe is then detected with an electrode polarized at the appropriate potential. This work aims to study the single-impact electrochemistry of redox liposomes in different conditions. Previous results indicate that the addition of a surfactant to a liposomal suspension leads to their rupture when they stochastically collide with an ultramicroelectrode.[3] Similarly, virulence factors increase their release or electrolysis of contents upon impact with an ultramicroelectrode.[4] Chronoamperometry measurements recorded at the ultramicroelectrode polarized at the redox potential of the electrochemical probe show impact events (vesicle blocking) and opening events (vesicle reactor) when the encapsulated redox probe is released by the liposome, which are traced back to the presence of pathogenic bacteria.

Blinded, randomized, placebo-controlled study of the efficacy of bupivacaine liposomal suspension using static bodyweight distribution and subjective pain scoring in dogs after tibial plateau leveling osteotomy.

Blinded, randomized, placebo-controlled study of the efficacy of bupivacaine liposomal suspension using static bodyweight distribution and subjective pain scoring in dogs after tibial plateau leveling osteotomy.

Effect of curvature on bilayer thickness of liposome suspensions in water

The bilayer thickness of different sizes of SOPC lipid liposomes is measured using small-angle neutron scattering (SANS) at 30 °C and a model is developed to estimate the bilayer thickness of liposome based on its diameter. Three different sizes of liposome suspensions are prepared by extruding the suspension through 30 nm, 100 nm, and 200 nm membrane pore sizes. The bilayer thickness of liposomes is measured for these suspensions using small-angle neutron scattering and the results show a slight reduction in bilayer thickness as liposome size increases. The average diameter of liposomes in these extruded suspensions varies from 59 nm to 109 nm as measured by dynamic light scattering. A model is developed that calculates the bilayer thickness depending on the diameter of the liposome. The model shows a decrease in bilayer thickness as liposome size increases. However, the calculated bilayer thickness drops to a very small extent with the increase in liposome diameter. We also study the effect of the addition of ethanol on the bilayer thickness of liposomes. SANS measurements find that the bilayer thickness of liposomes decreases after adding ethanol to liposome suspensions. The decrease in bilayer thickness in ethanol is of similar extent for various sizes of liposomes and it reduces by 12%–15% at a concentration of 20 vol% ethanol.

Response to: Does Liposomal Bupivacaine Injectable Suspension Peripheral Nerve Block Further Aid in Decreasing At-home Narcotic Utilization in Children and Adolescents After Anterior Cruciate Ligament Reconstruction.

Response to: Does Liposomal Bupivacaine Injectable Suspension Peripheral Nerve Block Further Aid in Decreasing At-home Narcotic Utilization in Children and Adolescents After Anterior Cruciate Ligament Reconstruction.