[Antifriction and anti-wear performances of bionic lubricating fluid containing gelatin nanoparticles for artificial joint materials].

Objective: The antifriction and antiwear effects of gelatin nanoparticles (GLN-NP) on artificial joint materials in bionic joint lubricant were investigated to provide a theoretical basis for the development of new bionic joint lubricant. Methods: GLN-NP was prepared by cross-linking collagen acid (type A) gelatin with glutaraldehyde by acetone method, and the particle size and stability of GLN-NP were characterized. The biomimetic joint lubricants with different concentrations were prepared by mixing 5, 15, and 30 mg/mL GLN-NP with 15 and 30 mg/mL hyaluronic acid (HA), respectively. The friction reduction and antiwear effects of the biomimetic joint lubricants on zirconia ceramics were investigated on a tribometer. The cytotoxicity of each component of bionic joint lubricant on RAW264.7 mouse macrophages was evaluated by MTT assay. Results: The particle size of GLN-NP was about 139 nm, and the particle size distribution index was 0.17, showing a single peak, indicating that the particle size of GLN-NP was uniform. In complete culture medium, pH7.4 PBS, and deionized water at simulated body temperature, the particle size of GLN-NP did not change more than 10 nm with time, indicating that GLN-NP had good dispersion stability and did not aggregate. Compared with 15 mg/mL HA, 30 mg/mL HA, and normal saline, the friction coefficient, wear scar depth, width, and wear volume were significantly reduced by adding different concentrations of GLN-NP ( P<0.05); there was no significant difference between different concentrations of GLN-NP ( P>0.05). Biocompatibility test showed that the cell survival rate of GLN-NP, HA, and HA+GLN-NP solution decreased slightly with the increase of concentration, but the cell survival rate was more than 90%, and there was no significant difference between groups ( P>0.05). Conclusion: The bionic joint fluid containing GLN-NP has good antifriction and antiwear effect. Among them, GLN-NP saline solution without HA has the best antifriction and antiwear effect.

Biomimetic chitosan nanoparticles with simultaneous water lubricant and anti-inflammatory.

Rheumatoid arthritis (RA) is a chronic inflammatory immune and lubrication dysfunction disease that causes great damage to the joints. Herein, inspired by the unique biochemistry structure and excellent hydration of chondroitin sulfate (CHI) existing in joint system, one kind of novel polysaccharide nanoparticle lubricant, that is chitosan nanoparticles (CS NPs) grafting CHI (CS-CHI), is synthesized by one-step surface chemistry reaction. CHI with negative charges can form hydration layers on the surface of CS NPs, thus improving the lubricity of nanoparticles. Simultaneously, CS-CHI NPs have effective loading and sustained drug release ability for anti-inflammatory drug diclofenac sodium (DS), along with good biocompatibility. Finally, based on a collagen-induced rat RA model, in vitro animals experimental results indicate that the as-synthesized CS-CHI@DS NPs has obvious inhibitory effects on inflammatory factors and can effectively prevent the damaged cartilage from further destruction.

Upscaling of external lubrication from a compaction simulator to a rotary tablet press.

External lubrication is a highly valuable alternative lubrication method as it minimizes the negative impact on tablet properties encountered when using internal lubrication. In current study, experiments were performed with automated external lubrication systems implemented in a compaction simulator and rotary tablet press using three lubricants (magnesium stearate (MgSt), sodium stearyl fumarate (SSF) and glyceryl dibehenate (DBHG)). The effect of process parameters related to the tableting process (main compaction pressure and tableting speed) and external lubrication systems (spraying time, atomizing pressure, dust extraction system and lubricant feed rate) on the responses was studied for a placebo formulation which is non-processable without lubrication. Low and comparable ejection forces were recorded for all lubricants on both tablet presses. No negative effect on tensile strength was observed for process parameters of both external lubrication systems, irrespective of lubricant type. Disintegration times were slightly higher for SSF compared to MgSt and DBHG for the tablets produced on the rotary tablet press, linked to higher lubricant concentrations on the tablets for SSF, while disintegration times were similar for all lubricant types on the compaction simulator. The potential of external lubrication for implementation on production scale tableting equipment and during scale-up was demonstrated for multiple lubricants.

Impact of acetylation process of kraft lignin in development of environment-friendly semisolid lubricants.

The aim of this work was to study the influence of the acetylation process of kraft lignin on developing dispersions potentially applicable as new bio-based semisolid lubricants. Lignin was functionalized with acetic anhydride and pyridine as a catalyst by modifying different reaction variables (temperature, ratio of pyridine/acetic anhydride and time). Acetylated lignin was analyzed using FTIR, 1H and 13C NMR techniques, TGA, DSC and SEM to evaluate the chemical, morphological and thermal changes induced by the acetylation process. The influence of the acetylation process on the rheological and tribological properties of dispersions was related to the development of different microstructures, which depend on chemical and morphological properties of acetylated lignin. In this sense, two different rheological behaviours (gel-like or fluid-like) were found to depend on the reaction time. From the experimental results obtained, it can be concluded that the acetylation process is a key issue to modulate rheological and morphological properties of dispersions, resulting in an effective method to improve the compatibility of lignin and castor oil. Acetylated lignin with medium degrees of substitution with adequate morphological properties can be potentially used as an effective thickening agent to develop semisolid lubricants.

Screening of lubricants towards their applicability for external lubrication.

Internal lubrication is associated with decreasing tensile strength and prolonged disintegration. These effects can be minimized using external lubrication. In current study, six lubricants (magnesium stearate, sodium stearyl fumarate, stearic acid, glyceryl dibehenate, poloxamer 188 and sucrose monopalmitate) were processed with an external lubrication system implemented in a compaction simulator. The effect of process parameters related to the tableting process (main compaction pressure and tableting speed) and external lubrication system (spraying time, atomizing pressure and dust extraction system) on the responses was studied for a placebo formulation (80% mannitol - 20% microcrystalline cellulose). Internally lubricated blends (0.75 - 4%) were processed as reference. All lubricants proved successful in reducing ejection forces through external lubrication while yielding substantially lower lubricant concentrations compared to internal lubrication. No negative effect of external lubrication on tensile strength and disintegration time was observed, irrespective of lubricant type. Similar tensile strengths and disintegration times were measured for the different lubricants. This was in contrast to internal lubrication where a decrease in tensile strength and prolonged disintegration was generally observed. Additionally, the lubricant types affected tensile strength and disintegration differently. This study demonstrates the versatility of external lubrication as an alternative lubrication method for production of pharmaceutical tablets.

Unique ice dendrite morphology on state-of-the-art oil-impregnated surfaces.

Due to its multifaceted impact in various applications, icing and ice dendrite growth has been the focus of numerous studies in the past. Dendrites on wetting (hydrophilic) and nonwetting (hydrophobic) surfaces are sharp, pointy, branching, and hairy. Here, we show a unique dendrite morphology on state-of-the-art micro/nanostructured oil-impregnated surfaces, which are commonly referred to as slippery liquid-infused porous surfaces or liquid-infused surfaces. Unlike the dendrites on traditional textured hydrophilic and hydrophobic surfaces, the dendrites on oil-impregnated surfaces are thick and lumpy without pattern. Our experiments show that the unique ice dendrite morphology on lubricant-infused surfaces is due to oil wicking into the porous dendritic network because of the capillary pressure imbalance between the surface texture and the dendrites. We characterized the shape complexity of the ice dendrites using fractal analysis. Experiments show that ice dendrites on textured oil-impregnated surfaces have lower fractal dimensions than those on traditional lotus leaf-inspired air-filled porous structures. Furthermore, we developed a regime map that can be used as a design guideline for micro/nanostructured oil-impregnated surfaces by capturing the complex effects of oil chemistry, oil viscosity, and wetting ridge volume on dendrite growth and morphology. The insights gained from this work inform strategies to reduce lubricant depletion, a major bottleneck for the transition of micro/nanostructured oil-impregnated surfaces from bench-top laboratory prototypes to industrial use. This work will assist the development of next-generation depletion-resistant lubricant-infused ice-repellent surfaces.

Hospital-prepared low-dose atropine eye drops for myopia progression control using atropine sulfate injection diluted in normal saline and lubricants.

OBJECTIVE: As low-dose atropine eye-drops for myopia progression control prepared in-house by diluting the commercial 0.1% atropine eye-drop with sterile water or normal saline has been a common practice whereas atropine injection is readily available and could be a more feasible alternative, this study aimed to assess the properties of the in-house low-dose atropine eye-drops prepared by diluting the atropine injection in two solvents and tested in two temperature conditions. RESULTS: The 0.01% atropine eye-drops contains no bacteria, fungi, or particulate matter. The levels of atropine sulfate on all samples were comparable to the freshly prepared samples at the 12th week, regardless of the solvents used or storage conditions. The low-dose atropine eye-drops prepared from readily available atropine sulfate injection at healthcare facilities could be an alternative to commercial products.

Lubricant for reducing perineal trauma: A systematic review and meta-analysis of randomized controlled trials.

AIM: To assess the effect of lubricants on reducing perineal trauma during vaginal delivery. METHODS: PubMed, Embase, the Cochrane Library, CINAHL, China National Knowledge Infrastructure, China Biology Medicine disc, WanFang databases, and ClinicalTrials.gov, were searched for literature up to 25 June 2021. Randomized controlled trials published in English or Chinese that compared the vaginal application of lubricant with standard care for women were included. Two reviewers independently performed study screening, data extraction, risk of bias assessment, and certainty of evidence assessment. Pooled effect sizes and corresponding 95% confidence intervals (CI) were calculated using meta-analysis. RESULTS: Nineteen trials enrolling 5445 pregnant women were included. Compared with standard care, women using lubricants had a lower incidence of perineal trauma (risk ratio [RR] 0.84, 95% CI 0.76-0.93; low certainty evidence), second-degree perineal laceration (RR 0.72, 95% CI 0.64-0.82; moderate certainty evidence) and episiotomy (RR 0.77, 95% CI 0.62-0.96; very low certainty evidence), and had a shorter duration of the second-stage labor (MD -13.72 min, 95% CI -22.68 to -4.77; very low certainty evidence). CONCLUSION: Lubricants might reduce the incidence of perineal trauma, especially second-degree perineal laceration, and shorten the duration of the second-stage labor. More well-designed studies will continue developing high-quality evidence in this field.

Hydrogen permeation through steel during cathodic polarization of lubricating oils in a modified Devanathan-Stachurski cell.

In lubricated tribo-contacts, hydrogen ingress in steel is possible due to chemical reactions of lubricant components like base oils or additives, and/or contamination upon service particularly water, and/or corrosion processes, and/or electrostatic fields or current flow. Absorbed by the metal, atomic hydrogen may cause serious deleterious effects on the physical-chemical and mechanical properties, reducing the material's ability to withstand the design loads. The present research work is focused on analyzing the influence of electric field on lubricating oils in contact with steel surface. In order to evaluate the possibility of atomic hydrogen generation and permeation into the steel under cathodic polarization of lubricating oils the electrochemical permeation technique developed by Devanathan and Stachurski is used. The input cell of a Devanathan-Stachurski set up is appropriately modified by realizing a very close distance between the working electrode (steel membrane) and a Pt counter electrode with the oil between. This significantly increases the sensibility of the set up and allows the application of larger voltage and higher temperature to enable hydrogen generation from lubricating oils. The complex effects of cathodic polarization, temperature, additives and presence of water in model lubricating oils on atomic hydrogen permeation into steel is discussed.

Treatment of Sexual Dysfunction in Women with Systemic Autoimmune Rheumatic Disorders: A Systematic Review.

INTRODUCTION: Female sexual dysfunction (SD) is an under-recognized and undertreated problem in patients with systemic autoimmune rheumatic disorders (SARDs). OBJECTIVES: To summarize and evaluate the existing treatment modalities for SD in females with SARDs. METHODS: A systematic review was conducted following the PRISMA guidelines. Electronic databases were searched up to April 2022 for studies that assessed the use of pharmacological and non-pharmacological treatment modalities for the management of SD in females with SARDs. Randomized and observational studies were included. (PROSPERO: CRD42022296381). RESULTS: Seven studies with 426 females with SD were included. Seven different treatment modalities belonging to 5 different classes (androgen therapy, phosphodiesterase-5 inhibitors, exercise, education and local creams) were evaluated in patients with systemic lupus erythematosus, rheumatoid arthritis and systemic sclerosis. The majority of the studies were of low methodological quality. Standardized patient education and 8-week aerobic walking programs were successful in improving female SD. Local creams improved dyspareunia in females with systemic sclerosis. Testosterone did not significantly improve SD in patients with systemic lupus erythematosus. Accordingly, tadalafil did not result in a significant improvement of SD in females with systemic sclerosis, based on the Female Sexual Function Index. CONCLUSION: There is a lack of sufficient evidence to recommend a certain management strategy for SD in females with SARDs. Nonpharmacological therapy and lubricant creams may be beneficial in females with SARDs. No benefit was demonstrated after androgen therapy or tadalafil. Still, no definite conclusions can be drawn due to the important limitations of the available literature. Overall, our results may be considered preliminary and further research in the field is mandatory. Baniotopoulos P, Pyrgidis N, Minopoulou I, et al. Treatment of Sexual Dysfunction in Women with Systemic Autoimmune Rheumatic Disorders: A Systematic Review. Sex Med Rev 2022;10:520-528.

Viscosity of Nanoconfined Branched-Chain Fatty Acids Studied by Resonance Shear Measurements.

Lubricant performance can be improved using additives such as organic friction modifiers (OFMs) and is influenced by their conformation and properties in the space confined between the substrate surfaces, rendering the detailed property analysis of confined OFMs and lubricants a matter of high practical significance. To date, studies on fatty acids as confined OFMs have mainly focused on linear- and unsaturated-chain molecules, leaving branched-chain structures underexplored. To bridge this gap, we used resonance shear measurements in this study to probe the viscosity of two branched-chain C18 fatty acids (isostearic acid T and isostearic acid) confined between mica surfaces at different applied normal loads (L) and surface separation distances (D). The viscosity parameter (bs) of both acids significantly increased at D < ∼4 nm because of structuring and was lower for isostearic acid than that for isostearic acid T at L > ∼0.6 mN. This reversal of bulk viscosity order under nanoconfinement was ascribed to the ability of the bulky methyl-substituted side chain of isostearic acid to prevent ordering in the nanospace between the mica surfaces and thus preserve fluidlike properties. The obtained results provide fundamental insights into the lubricity of branched-chain fatty acids and are expected to promote the development of novel high-performance OFMs.

A compactibility-based lubricant dispersion model describing the effect of formulation and paddle speed.

In rotary tablet presses, the powder flow into the dies is typically facilitated by paddle feeder. For internally lubricated formulations, the shear forces exerted by the paddle rotation can result in a considerable decrease in tablet strength due to the dispersion of lubricant agglomerates. Available models to describe the lubricant dispersion in paddle feeder allow only a limited quantitative description and transferability of the process. This study introduces an empirical dispersion kinetic which is able to precisely describe the reduction of compactibility due to the shear stresses inside the paddle feeder, even for inhomogeneously flowing material. Additionally, by blending different grades of magnesium stearate at three levels of lubricant concentration with two different grades of microcrystalline cellulose, the impact of bulk properties on the lubrication dispersion in the feed frame was investigated. It was shown, that for a given formulation, the kinetics of compactibility reduction are comparable for different magnesium stearate concentrations. Additionally, the bulk properties of the applied magnesium stearate grade critically affect the dispersion kinetics as well as the maximum compactibility reduction inside the feed frame. In summary, the developed model represents a meaningful extension of the currently available process models for pharmaceutical tablet lubrication.

Drug Utilization Study in Outpatient Department of Ophthalmology in Tertiary Care Hospital.

Background The advancement in drug development and availability of newer drugs has improved overall health services including decrease in mortality and hospital stay. Along, it has brought negative impacts such as polypharmacy and associated adverse drug reactions and antimicrobial resistance. Drug utilization research is an essential approach to understand the drug use pattern, identify the early signs of such irrational drug use and to improve quality of drug use. Objective To study the drug utilization pattern in the Ophthalmology Outpatient department (OPD) of Dhulikhel Hospital, Kathmandu University Hospital (DH-KUH). Method A descriptive, cross sectional study was conducted from March 2019 to August 2019 in patients attending OPD of Ophthalmology in Dhulikhel Hospital, Kathmandu University Hospital. Prescriptions of 311 patients were analyzed using World Health Organization (WHO) International Network of Rational Use of Drug (INRUD) and additional other indices. The descriptive data was presented in mean and standard deviation. Result The average number of drugs per prescription was 2.10±1.35. Out of total 311 prescriptions, drugs prescribed in generic name were 152 (23.30%). Total antibiotics encountered were 247 (37.90%) and total drugs prescribed from National Essential Medicine List (NEML) were 371 (56.90%). Antibiotics 247 (37.90%) were the most commonly prescribed drugs followed by lubricants 146 (22.40%). Conclusion Practice of polypharmacy was very high. Most of the drugs were prescribed in brand names and antibiotics were the most frequently used drugs.

Efficacy of single dose dermatological 0.1% Tacrolimus Ointment in the treatment of vernal keratoconjunctivitis.

Objectives: To assess the safety of dermatological 0.1% tacrolimus ointment when used topically and its efficacy in the treatment of vernal keratoconvinctivtis. METHODS: The quasi-experimental, multi-centre study was conducted at the Gujranwala Medical College/District Headquarters Teaching Hospital, Gujranwala, and the Gomal Medial College/Mufti Mehmood Teaching Hospital, Dera Ismail Khan, Pakistan, from July 2019 to March 2020, and comprised patients of severe vernal keratoconvinctivtis. Symptoms and clinical signs were graded on a pre-devised scale. Patients were given small amount of tacrolimus 0.1% ointment applied to the inferior conjunctival fornix before going to bed. The duration of treatment was 3 months and the patients were followed up for up to 6 months. Data was analysed using SPSS 20. RESULTS: Of the 50 patients, 30(60%) were males and 20(40%) were females. The overall mean age was 10.64±3.199 years. Mean symptom score and clinical signs score gradually reduced on each follow-up (p<0.05). Mild recurrence was noted in 12(24%) patients who were managed with lubricants and anti-histamine topical drops. No complication was noted. CONCLUSIONS: Tacrolimus 0.1% was found to be effective and safe in the treatment of severe refractory vernal keratoconvinctivtis even when given once a day. Clinical Trial Registration: Chinese Clinical Trial Registry Id: ChiCTR2000031929 link: www.chictr.org.cn/hvshowproject.aspx?id=28053.

Influence of hyaluronic acid on intra-articular friction - a biomechanical study in whole animal joints.

BACKGROUND: Cartilage is a mechanically highly stressed tissue in the human body and an important part of synovial joints. The joint cartilage is lubricated by synovial fluid with hyaluronic acid (HA) as main component. However, in joints with osteoarthritis HA has a lower concentration and molecular weight compared to healthy joints. In recent years, the intra-articular injection of therapeutic HA lubricant, has become a popular therapy. The effect of HA application on the friction of a complete joint with physiological movement needs to be further determined. METHODS: The aim of the present study was to evaluate the lubrication effect of the joint by three lubricants (NaCl, fetal calf serum (FCS) and HA) and their effect on the friction in nine complete ovine carpo-metacarpal joints. The joints were mounted on a material testing machine and a physiological movement with 10° rotation was simulated with ascending axial load (100 - 400 N). Specimens were tested native, with cartilage damage caused by drying out and relubricated. Dissipated energy (DE) as a measure of friction was recorded and compared. RESULTS: Investigating the effect of axial load, we found significant differences in DE between all axial load steps (p < .001), however, only for the defect cartilage. Furthermore, we could document an increase in DE from native (Mean: 15.0 mJ/cycle, SD: 8.98) to cartilage damage (M: 74.4 mJ/cycle, SD: 79.02) and a decrease after relubrication to 23.6 mJ/cycle (SD: 18.47). Finally, we compared the DE values for NaCl, FCS and HA. The highest values were detected for NaCl (MNorm = 16.4 mJ/cycle, SD: 19.14). HA achieved the lowest value (MNorm = 4.3 mJ/cycle, SD: 4.31), although the gap to FCS (MNorm = 5.1 mJ/cycle, SD: 7.07) was small. CONCLUSIONS: We were able to elucidate three effects in joints with cartilage damage. First, the friction in damaged joints increases significantly compared to native joints. Second, especially in damaged joints, the friction increases significantly more with increased axial load compared to native or relubricated joints. Third, lubricants can achieve an enormous decrease in friction. Comparing different lubricants, our results indicate the highest decrease in friction for HA.

Effect of mineral oil as a lubricant to collect feces from cats for microbiome studies.

BACKGROUND: Fecal specimens are critical for disease screening, diagnosis, and gut microbiome research. For domestic cats, lubricants are often necessary to obtain a sufficient quantity of sample. However, the effect of lubrication on feline microbiome analysis has not been assessed. OBJECTIVES: To evaluate if lubrication using mineral oil during cat feces sample collection affects the DNA extraction, metagenomic sequencing yield, and the microbial composition and diversity in subsequent gut microbiome analyses. ANIMALS: Eight 6-year-old male, neutered, domestic short-haired cats housed in a research facility. METHODS: Cohort study. The gut microbiomes were investigated for fecal sample collection with and without lubrication using whole-genome shotgun metagenomic sequencing. RESULTS: Fecal specimens were collected using a fecal loop under sedation without lubrication and with mineral oil lubrication. There were no significant differences between the 2 groups in the microbial DNA yield in ng/mg fecal sample (75.75 [25.8-125.7] vs 60.72 [33.49-87.95], P = .95), metagenomic sequencing yield in Gbp (10.31 [6.29-14.32] vs 13.53 [12.04-15.02], P = .2), proportion of host contamination (0.1 [0.02-0.18] vs 0.15 [0-0.3], P = .84), relative taxonomy abundance (P > .8), or the number of microbial genes covered (408 132 [341 556-474 708] vs 425 697 [358 505-492 889], P = .31). CONCLUSIONS AND CLINICAL IMPORTANCE: Fecal sampling with mineral oil lubrication did not change the microbial DNA extraction yield, metagenomic sequencing yield, level of host contamination, the microbial composition and diversity in subsequent gut microbiome analyses. Here we reported a proven cat-friendly protocol for fecal sample collection in clinical and research setting for gut microbiome analyses.

A review on properties, challenges and commercial aspects of eco-friendly biolubricants productions.

Lubricants operate as antifriction media, preserving machine reliability, facilitating smooth operation, and reducing the likelihood of frequent breakdowns. The petroleum-based reserves are decreasing globally, leading to price increases and raising concerns about environmental degradation. The researchers are concentrating their efforts on developing and commercializing an environmentally friendly lubricant produced from renewable resources. Biolubricants derived from nonedible vegetable oils are environmentally favorable because of their non-toxicity, biodegradability, and close to net zero greenhouse gas emissions. The demand for bio lubricants in industry and other sectors is increasing due to their non-toxic, renewable, and environmentally friendly nature. Good lubrication, anti-corrosion, and high flammability are characteristic properties of vegetable oils due to their unique structure. This study presents several key properties of nonedible oils that are used to produce lubricants via the transesterification process. Bibliometric analysis is also performed, which provides us with a better understanding of previous studies related to the production of bio lubricants from the transesterification process. Only 371 published documents in the Scopus database were found to relate to the production of bio lubricants using the transesterification process. The published work was mostly dominated by research articles (286; 77.088%). Significant development can be seen in recent years, with the highest occurrence in 2021, reaching 68 publications accounting for 18.38% of the total documents. In the second step, (i) the authors with the most number of publications; (ii) journals with the most productions; (iii) most productive countries; and (iv) the authors' most frequently used keywords were evaluated. These results will provide a pathway for researchers interested in this field. Lastly, recommendation is made on research gaps to device possible strategies for its commercialization.

MTN-033: a Phase 1 Study Comparing Applicator versus "as Lubricant" Delivery of Rectal Dapivirine Gel.

Data to inform behaviorally congruent delivery of rectal microbicides as lubricants are scant. Dapivirine (DPV) is a nonnucleoside reverse transcriptase inhibitor which has been demonstrated to be well-tolerated and efficacious in multiple clinical trials when used in a vaginal ring formulation. DPV gel administered rectally with an applicator was found to be well-tolerated in a phase 1 clinical trial. MTN-033, a single site, open label, sequence randomized, crossover study, enrolled HIV-negative men to receive 0.05% DPV gel intrarectally using an applicator (2.5 g) and self-administered on an artificial phallus as lubricant (up to 10 g). The study evaluated the pharmacokinetics (in plasma, rectal fluid, and mucosal rectal tissue), safety, acceptability, and pharmacodynamics of DPV gel when applied rectally. Statistical comparisons between methods of application were performed using mixed effects models or Wilcoxon's signed rank tests. Sixteen participants used DPV gel by applicator and 15/16 participants used gel as lubricant (mean, 1.8 g; SD, 0.8). DPV plasma AUC0-24h after use as lubricant was estimated to be 0.41 times the AUC0-24h (95% CI 0.24, 0.88) after use with applicator. While DPV was quantifiable in plasma and luminal fluid, it was not quantifiable in tissue for both applicator and as lubricant administration. No related adverse events (AE) were reported, and 15/15 participants felt the gel was easy to use. Evidence of local delivery and systemic absorption of DPV when dosed as an anal lubricant supports the feasibility and potential for development of lubricant-delivered rectal microbicides. There were no safety concerns associated with use of DPV gel and participants reported finding it easy to use. However, lower DPV exposure in plasma and lack of quantifiable DPV in rectal tissue indicate that higher potency, concentration, and longer half-life antiretrovirals with optimized formulations will be needed to achieve protective tissue concentrations.

Probing Molecular Interactions of Antibody Drugs, Silicone Oil, and Surfactant at Buried Interfaces In Situ.

Antibody drugs have been rapidly developed to cure many diseases including COVID-19 infection. Silicone oil is commonly used as a lubricant coating material for devices used in the pharmaceutical industry to store and administer antibody drug formulations. However, the interaction between silicone oil and antibody molecules could lead to the adsorption, denaturation, and aggregation of antibody molecules, impacting the efficacy of antibody drugs. Here, we studied the molecular interactions between antibodies and silicone oil in situ in real time. The effect of the surfactant on such interactions was also investigated. Specifically, the adsorption dynamics of a bispecific antibody (BsAb) onto a silicone oil surface without and with different concentrations of the surfactant PS80 in antibody solutions were monitored. Also the possible lowest effective PS80 concentrations that can prevent the adsorption of BsAb as well as a monoclonal antibody (mAb) onto silicone oil were measured. It was found that different concentrations of PS80 are required for preventing the adsorption of different antibodies. Both BsAB and mAB denature on silicone oil without a surfactant. However, for a low surfactant concentration in the solution, although the surfactant could not completely prevent the antibody from adsorption, it could maintain the native structures of adsorbed BsAb and mAb antibodies on silicone oil. This is important knowledge, showing that to prevent antibody aggregation on silicone oil it is not necessary to add surfactant to a concentration high enough to completely minimize protein adsorption.

Slippery liquid-infused porous surface (SLIPS) with super-repellent and contact-killing antimicrobial performances.

Slippery liquid-filled porous surfaces (SLIPS) have attracted extensive research attention for their unique repellent properties, but such surfaces typically lack essential bactericidal activity and cannot defend against the spread of bacteria once bacterial contamination occurs. Herein, a slippery liquid-infused porous surface (SLIPS), endowed with both super-repellent and contact-killing antimicrobial performances is reported. Firstly, polystyrene (PS) based porous structures are developed via a facile microphase separation technique with poly(ethylene glycol) (PEG) as the sacrifice template. The porous surface was then covalently modified by 3-(trimethoxysilyl)propyl dimethyl undecyl ammonium chloride (QAC-Silane) to get the contact-killing antimicrobial performances. After lubricant (silicone oil) is introduced to the porous structure, the SLIPS surface demonstrates remarkably high super-repellence against both Gram-positive and negative bacteria, and also maintains essential contact-killing antimicrobial activities from the fixed QAC-11 groups, once the infused lubricant was depleted. Also, this surface demonstrates a reduced coefficient of friction (COF) of ∼56% as compared to that of the control flat surface. Moreover, this SLIPS surface can be easily realized on various substrates, such as silica glass, polycarbonate (PC), polyethylene terephthalate (PET), polyethylene (PE) and silicone catheter tube. Owing to its simple, low-cost and fast fabrication approach, this kind of surface may find unique biomedical applications where an effective antibacterial performance and lubricity are highly needed.