Local Drug Research Articles

Chemotherapeutic Agents in Periodontics: A Review

"Selman Waksman" first used the term "antibiotic" in 1942 to refer to any material produced by a bacterium that inhibits the growth of other micro-organisms in high dilution. The pathogenic bacteria, the patient, and the medication are the three main components of the antibiotic periodontal therapy idea. Patients with attachment loss or with aggressive types of periodontitis or those with periodontitis linked with underlying medical conditions are the best candidates for systemic antimicrobial therapy. The three main objectives of Periodontal Therapy are disrupting biofilms, suppressing potential periodontal pathogens throughout the entire oral cavity, and halting the illness. The microbial etiology of inflammatory periodontal disease provides the rationale for the use of antibiotic medication in periodontal therapy. This idea is predicated on the idea that a certain bacterium causes destructive periodontal disease and that antibiotic agents can be present in humans in doses greater than those required to kill or inhibit infections. Keywords: Antibiotics, Systemic drug delivery, Local drug delivery, Periodontal therapy.

Dynamic Hydrogels against Infections: From Design to Applications.

Human defense against infection remains a global topic. In addition to developing novel anti-infection drugs, therapeutic drug delivery strategies are also crucial to achieving a higher efficacy and lower toxicity of these drugs for treatment. The application of hydrogels has been proven to be an effective localized drug delivery approach to treating infections without generating significant systemic adverse effects. The recent emerging dynamic hydrogels further show power as injectable formulations, giving new tools for clinical treatments. In this review, we delve into the potential applications of dynamic hydrogels in antibacterial and antiviral treatments and elaborate on their molecular designs and practical implementations. By outlining the chemical designs underlying these hydrogels, we discuss how the choice of dynamic chemical bonds affects their stimulus responsiveness, self-healing capabilities, and mechanical properties. Afterwards, we focus on how to endow dynamic hydrogels with anti-infection properties. By comparing different drug-loading methods, we highlight the advantages of dynamic chemical bonds in achieving sustained and controlled drug release. Moreover, we also include the design principles and uses of hydrogels that possess inherent anti-infective properties. Furthermore, we explore the design principles and applications of hydrogels with inherent anti-infective properties. Finally, we briefly summarize the current challenges faced by dynamic hydrogels and present a forward-looking vision for their future development. Through this review, we expect to draw more attention to these therapeutic strategies among scientists working with chemistry, materials, as well as pharmaceutics.

Storage implications on the microbiological quality of some locally manufactured pharmaceuticals

Pharmaceutical products non-sterile are expected to have a minimal microbial load which must not exceed the limits as stated in pharmacopoeia monographs. This study attempted to evaluate storage implications on the microbiological quality of some non-sterile pharmaceutical products manufactured locally in some states in south east Nigeria. Twenty brands of pharmaceutical products comprising 13 tablets, 5 capsules and 2 suspension procured from patent medicine and local drug markets in Aba and Enugu states were stored at room temperature (25oC) for 6 months. Microbial growth was evaluated at 0 and 6 months using standard microbiological procedures including Total aerobic bacteria plate count, isolation, characterization and identification of microbial contaminants. The results from the study showed that 55% and 30% of the pharmaceutical products had bacteria and fungi contamination at 0 month which increased to 70% and 50% at 6 months storage period respectively. Statistical analysis showed there was a significant increase (p < 0.05) in growth of micro-organisms at 6 months for both bacteria and the fungi/moulds (p < 0.05). The isolated bacteria were Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli while the fungi include Trichosporonasahii, Curvularia bothriochloae, Candida albicans, Candida parapsilosis. All contaminated samples had microbial counts above the British Pharmacopoeia (BP) acceptabl limit of 103 and 102 CFU/ml for bacteria and fungi respectively. This can be attributed to poor adherence to current Good Manufacturing Practice (cGMP) by the manufacturers. Thus, it is recommended that manufacturers adhere strictly to cGMP and storage conditions stated on these pharmaceutical products followed strictly during distribution and storage to reduce the levels of microbial contamination.

3D-printed short nanofibers/hydrogel-based vaginal films as a novel system for the delivery of anti-HIV microbicide drugs

Acquired immunodeficiency syndrome (AIDS) is a global epidemic that affects the lives of millions of young women, particularly those who live in poverty-stricken regions and engage in unsafe sexual behaviors, forcing the development of unique pre-exposure anti-HIV prophylaxis tools. Using a combination of antiretroviral medications with various antiviral mechanisms significantly improves the prognosis for HIV patients. The integration of 3D printing technology, short nanofiber technology, and hydrogel into a single system known as “3D-printed nanocomposites” is an emerging approach that is gaining traction in tissue engineering, regenerative medicine, and biomedical applications. Based on these foundations, the current study aims to develop, for the first time, a 3D-printed short nanofiber/film for the vaginal delivery of ritonavir and efavirenz in a fixed-dose combination. To identify an optimal 3D-printable short nanofibers/hydrogel formulation, multiple formulations, and fragmentation methods were investigated. Following that, the generated vaginal films were evaluated using several physicochemical characterizations, mechanical properties measurements, and in vitro release studies. The findings revealed that only cryocutting is effective for polycaprolactone nanofiber fragmentation. The 3D-printed short nanofibers-loaded films had an ultimate tensile strength of 6.75 ± 1.27 MPa and elongation at break of 262.67 ± 44.32 MPa, suggesting their reliability for handling and vaginal application. Furthermore, the in vitro release study demonstrated that rapid EFZ release occurred during the first 45 min, whereas RIT release lasted more than 72 h, indicating that the complex drug release profile was met. In summary, the study emphasizes that 3D printing of short nanofiber-based films is likely to be an effective platform for localized vaginal drug delivery, particularly anti-HIV therapies.

Drug Integrating Amphiphilic Nano-Assemblies: 2. Spatiotemporal Distribution within Inflammation Sites.

The need for chronic systemic immunosuppression, which is associated with unavoidable side-effects, greatly limits the applicability of allogeneic cell transplantation for regenerative medicine applications including pancreatic islet cell transplantation to restore insulin production in type 1 diabetes (T1D). Cell transplantation in confined sites enables the localized delivery of anti-inflammatory and immunomodulatory drugs to prevent graft loss by innate and adaptive immunity, providing an opportunity to achieve local effects while minimizing unwanted systemic side effects. Nanoparticles can provide the means to achieve the needed localized and sustained drug delivery either by graft targeting or co-implantation. Here, we evaluated the potential of our versatile platform of drug-integrating amphiphilic nanomaterial assemblies (DIANAs) for targeted drug delivery to an inflamed site model relevant for islet transplantation. We tested either passive targeting of intravenous administered spherical nanomicelles (nMIC; 20-25 nm diameter) or co-implantation of elongated nanofibrils (nFIB; 5 nm diameter and >1 μm length). To assess the ability of nMIC and nFIB to target an inflamed graft site, we used a lipophilic fluorescent cargo (DiD and DiR) and evaluated the in vivo biodistribution and cellular uptake in the graft site and other organs, including draining and non-draining lymph nodes, after systemic administration (nMIC) and/or graft co-transplantation (nFIB) in mice. Localized inflammation was generated either by using an LPS injection or by using biomaterial-coated islet-like bead implantation in the subcutaneous site. A cell transplant inflammation model was used as well to test nMIC- and nFIB-targeted biodistribution. We found that nMIC can reach the inflamed site after systemic administration, while nFIB remains localized for several days after co-implantation. We confirmed that DIANAs are taken up by different immune cell populations responsible for graft inflammation. Therefore, DIANA is a useful approach for targeted and/or localized delivery of immunomodulatory drugs to decrease innate and adaptive immune responses that cause graft loss after transplantation of therapeutic cells.

MOF-based nanoparticles for tumor-targeted protein degradation and photodynamic therapy induce enhanced anti-tumor immunity

Combining proteolysis targeting chimeras (PROTACs) with photodynamic therapy (PDT) is a promising strategy for cancer treatment. However, the therapeutic efficacy is impaired due to the poor water solubility or the unsatisfactory tumor distribution of drugs. Herein, we developed a Hyaluronan (HA) coating MOF-based nanoplatform (ZMCH) to achieve the combined therapy of PROTACs and PDT with tumor-specific delivery and local drug release. The PROTACs molecules and photosensitizers could be easily wrapped into the nanoparticles via the self-assembly of zinc ions and 2-methylimidazole, which is a universal encapsulation approach for the conventional PROTACs or photosensitizers. As a proof-of-concept, we demonstrated that the designed ZMCH nanoreactor effectively suppresses tumor growth in the 4T1-tumor-bearing mice model, resulting from the synergistic effect of MZ1-mediated protein degradation and the Ce6-mediated reactive oxygen species (ROS) damage. Importantly, the ZMCH-induced therapy exhibited the enhanced antitumor T-cell immunity by regulating immunosuppressive tumor microenvironment, thereby effectively inhibiting tumor metastasis in the lungs. This work thus provides a novel approach and insights for the combination therapy of protein degradation and PDT in clinical cancer treatment.

Metal organic framework-based polymeric hydrogel: A promising drug delivery vehicle for the treatment of breast cancer

The constraints associated with current cancer therapies have inspired scientists to develop advanced, precise, and safe drug delivery methods. These delivery systems boost treatment effectiveness, minimize harm to healthy cells, and combat cancer recurrence. To design advanced drug delivery vehicle with these character, in the present manuscript, we have designed a self-healing and injectable hybrid hydrogel through synergistically interacting metal organic framework, CuBTC with the poly(vinyl alcohol) (PVA). This hybrid hydrogel acts as a localized drug delivery system and was used to encapsulate and release the anticancer drug 5-Fluorouracil selectively at the targeted site in response to the physiological pH. The hydrogel was formed through transforming the gaussian coil like matrix of PVA-CuBTC into a three-dimensional network of hydrogel upon the addition of crosslinker; borax. The biocompatible character of the hydrogel was confirmed through cell viability test. The biocompatible hybrid hydrogel then was used to encapsulate and studied for the pH responsive release behavior of the anti-cancer drug, 5-FU. The in vitro cytotoxicity of the drug-loaded hydrogel was evaluated against MCF-7 and HeLa cells. The study confirms that the hybrid hydrogel is effective for targeted and sustained release of anticancer drugs at cancer sites.

Novel nano-in-micro fabrication technique of diclofenac nanoparticles loaded microneedle patches for localised and systemic drug delivery

Diclofenac, a nonsteroidal anti-inflammatory drug, is commonly prescribed for managing osteoarthritis, rheumatoid arthritis, and post-surgical pain. However, oral administration of diclofenac often leads to adverse effects. This study introduces an innovative nano-in-micro approach to create diclofenac nanoparticle-loaded microneedle patches aimed at localised, sustained pain relief, circumventing the drawbacks of oral delivery. The nanoparticles were produced via wet-milling, achieving an average size of 200 nm, and then incorporated into microneedle patches. These patches showed improved skin penetration in ex vivo tests using Franz-cell setups compared to traditional diclofenac formulations. In vivo tests on rats revealed that the nanoparticle-loaded microneedle patches allowed for quick drug uptake and prolonged release, maintaining drug levels in tissues for up to 72 h. With a systemic bioavailability of 57 %, these patches prove to be an effective means of transdermal drug delivery. This study highlights the potential of this novel microneedle delivery system in enhancing the treatment of chronic pain with reduced systemic side effects.

Measuring protective efficacy and quantifying the impact of drug resistance: A novel malaria chemoprevention trial design and methodology.

Recently revised WHO guidelines on malaria chemoprevention have opened the door to more tailored implementation. Countries face choices on whether to replace old drugs, target additional age groups, and adapt delivery schedules according to local drug resistance levels and malaria transmission patterns. Regular routine assessment of protective efficacy of chemoprevention is key. Here, we apply a novel modelling approach to aid the design and analysis of chemoprevention trials and generate measures of protection that can be applied across a range of transmission settings. We developed a model of genotype-specific drug protection, which accounts for underlying risk of infection and circulating genotypes. Using a Bayesian framework, we fitted the model to multiple simulated scenarios to explore variations in study design, setting, and participant characteristics. We find that a placebo or control group with no drug protection is valuable but not always feasible. An alternative approach is a single-arm trial with an extended follow-up (>42 days), which allows measurement of the underlying infection risk after drug protection wanes, as long as transmission is relatively constant. We show that the currently recommended 28-day follow-up in a single-arm trial results in low precision of estimated 30-day chemoprevention efficacy and low power in determining genotype differences of 12 days in the duration of protection (power = 1.4%). Extending follow-up to 42 days increased precision and power (71.5%) in settings with constant transmission over this time period. However, in settings of unstable transmission, protective efficacy in a single-arm trial was overestimated by 24.3% if recruitment occurred during increasing transmission and underestimated by 15.8% when recruitment occurred during declining transmission. Protective efficacy was estimated with greater precision in high transmission settings, and power to detect differences by resistance genotype was lower in scenarios where the resistant genotype was either rare or too common. These findings have important implications for the current guidelines on chemoprevention efficacy studies and will be valuable for informing where these studies should be optimally placed. The results underscore the need for a comparator group in seasonal settings and provide evidence that the extension of follow-up in single-arm trials improves the accuracy of measures of protective efficacy in settings with more stable transmission. Extension of follow-up may pose logistical challenges to trial feasibility and associated costs. However, these studies may not need to be repeated multiple times, as the estimates of drug protection against different genotypes can be applied to different settings by adjusting for transmission intensity and frequency of resistance.

A randomised trial comparing block characteristics of a mixture versus sequential injections of lignocaine and ropivacaine for supraclavicular brachial plexus nerve block in patients undergoing upper limb surgery.

There is no consensus on the appropriate use of mixtures of local anaesthetic drugs in various combinations for nerve blocks. We intended to compare short-acting lignocaine and long-acting ropivacaine as a mixture versus undiluted sequential injections on block characteristics of ultrasound-guided (USG) supraclavicular brachial plexus block for upper limb surgeries. A double-blinded randomised study was conducted on 64 adult patients scheduled for upper limb surgery who received 15 mL each of 2% lignocaine with adrenaline and 0.75% ropivacaine as a 1:1 mixture in the mixed group (Group M) or sequential injections in the sequential group (Group S) by using a USG technique. The primary outcome was the percentage of participants with complete four nerve sensory blocks at 10 minutes post block injection. Secondary outcomes were sensory and motor block characteristics till 30 minutes, total duration of analgesia, sensory and motor block, and complications. Demographic characteristics and time taken for the procedure were similar. The percentage of participants with a complete four-nerve sensory block at 10 minutes was higher in Group S (69%) versus Group M (41%) (P = 0.04). Complete sensory and motor block rates were similar at 30 minutes. The block procedure time, total duration of analgesia, and sensory and motor block were similar in both groups. There were no major complications. Sequential lignocaine-ropivacaine, compared to the mixed injection technique, has a higher initial rate of sensory and motor block onset with a similar total block duration.

Precisely Programmable Degradation and Drug Release Profiles in Triblock Copolyether Hydrogels with Cleavable Acetal Pendants.

Hydrogels hold significant promise as drug delivery systems due to their distinct advantage of sustained localized drug release. However, the challenge of regulating the initial burst release while achieving precise control over degradation and drug-release kinetics persists. Herein, we present an ABA-type triblock copolymer-based hydrogel system with precisely programmable degradation and release kinetics. The resulting hydrogels were designed with a hydrophilic poly(ethylene oxide) midblock and a hydrophobic end-block composed of polyethers with varying ratios of ethoxyethyl glycidyl ether and tetrahydropyranyl glycidyl ether acetal pendant possessing different hydrolysis kinetics. This unique side-chain strategy enabled us to achieve a broad spectrum of precise degradation and drug-release profiles under mildly acidic conditions while maintaining the cross-linking density and viscoelastic modulus, which is unlike the conventional polyester-based backbone degradation system. Furthermore, programmable degradation of the hydrogels and release of active therapeutic agent paclitaxel loaded therein are demonstrated in an in vivo mouse model by suppressing tumor recurrence following surgical resection. Tuning of the fraction of two acetal pendants in the end-block provided delicate tailoring of hydrogel degradation and the drug release capability to achieve the desired therapeutic efficacy. This study not only affords a facile means to design hydrogels with precisely programmable degradation and release profiles but also highlights the critical importance of aligning the drug release profile with the target disease.

Challenges in Optimizing Nanoplatforms Used for Local and Systemic Delivery in the Oral Cavity.

In this study, we focused on innovative approaches to improve drug administration in oral pathology, especially by transmucosal and transdermal pathways. These improvements refer to the type of microneedles used (proposing needles in the saw), to the use of certain enhancers such as essential oils (which, besides the amplifier action, also have intrinsic actions on oral health), to associations of active substances with synergistic action, as well as the use of copolymeric membranes, cemented directly on the tooth. We also propose a review of the principles of release at the level of the oral mucosa and of the main release systems used in oral pathology. Controlled failure systems applicable in oral pathology include the following: fast dissolving films, mucoadhesive tablets, hydrogels, intraoral mucoadhesive films, composite wafers, and smart drugs. The novelty elements brought by this paper refer to the possibilities of optimizing the localized drug delivery system in osteoarthritis of the temporomandibular joint, neuropathic pain, oral cancer, periodontitis, and pericoronitis, as well as in maintaining oral health. We would like to mention the possibility of incorporating natural products into the controlled failure systems used in oral pathology, paying special attention to essential oils.

The role of curcumin in periodontal therapy: An update

Background: Periodontal diseases, including gingivitis and periodontitis, present a significant global health burden, particularly affecting adults and especially the aging population. The etiology involves complex interactions between microbial colonization and host immune-inflammatory responses, leading to tissue destruction and bone resorption. Current conventional treatments, primarily focused on mechanical debridement and antimicrobial agents, often have limitations and challenges, including antibiotic resistance and limited tissue regenerative potential. Curcumin, a polyphenolic compound derived from the Curcuma longa plant, has emerged as a promising adjunctive therapeutic agent owing to its remarkable pharmacological properties. Extensive preclinical research has revealed the potential anti-inflammatory, antioxidant, antimicrobial, and immunomodulatory effects of curcumin. These attributes make it a compelling candidate for addressing various aspects of periodontal pathogenesis. Furthermore, curcumin's capacity to in vitro inhibit various periodontopathogens such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans demonstrates its potential as a natural antimicrobial agent. Its adjunctive use in local drug delivery systems, such as gels or nanoparticles, holds promise for targeted delivery and sustained release within periodontal pockets, enhancing its therapeutic potential. However, challenges related to its bioavailability, stability, and dosage standardization need to be addressed forsuccessful clinical outcomes. Keywords: periodontal diseases; curcumin; bioactive compounds, inflammatory response, microbial dysbiosis

Effect of Intravaginal Application of Palasha Udumbaradi Ointment on Pelvic Organ Prolapse

Prolapse is a downward descent of the female pelvic organs as a result of weakness of the structures that normally retain them in position. The main symptoms of pelvic organ prolapse include micturition disturbances like stress incontinence, imperfect control of micturition, a feeling of lump coming down, postural low back ache, constipation and leucorrhoea. The management of pelvic organ prolapse includes preventive conservative and surgical measures. Surgery is indicated when conservative management fails. The three different conditions like Phalini, Prasramsini and Mahayoni vyapath mentioned by different Acharyas explain the prolapsed condition according to the stage and part prolapsed out. Palasha udumbaradi yoga mentioned in Bhaishajya Ratnavali containing ingredients such as Palasha beeja, Udumbara phala, Thilathaila and Madhu was taken for this study. The Lepa was applied in the modified form of an ointment. The study is an attempt to assess the effect of Palasha udumbaradi ointment on uterine prolapse. The ointment was applied intra vaginally. The presence of dense blood vasculature makes the vagina a potential site for local and systemic drug administration. The key advantages of vaginal drug delivery over oral administration is that this is able to circumvent the harsh gastric environment and also bypass hepatic first-pass metabolism. A 38 year woman with complaints of increased frequency of micturition, stress incontinence, burning micturition, low back ache and dyspareunia consulted the OPD of Govt. Ayurveda Medical College, Tripunithura. Palasha udumbaradi ointment was self-applied intra-vaginally. Administration of ointment was advised for 60 consecutive days excluding the days of menstruation with follow up on 90th day. Assessment was done on 0th, 30th and 60th day and follow up was done on 90th day using POP-Q Scale, urinary incontinence scale, and visual analogue scale.

Comparative efficacy of low-volume retrobulbar anesthesia using three commercial local anesthetics in adult horses.

To compare the efficacy of low-volume (5-mL) locoregional retrobulbar anesthesia ("retrobulbar block") by use of 3 commercial local anesthetic formulations. 8 healthy adult mares. A block-randomized, masked, controlled design was used. A single ultrasound-guided retrobulbar block was performed with 2% lidocaine, 2% mepivacaine, or 0.5% bupivacaine (n = 5 eyes/group). Contralateral eyes served as untreated controls. End points performed at baseline and time intervals up to 24 hours postblock included the following: assessment of neurophthalmic reflexes/responses, intraocular pressure, and vertical pupil diameter measurement, corneal and periocular esthesiometry, and observation for adverse effects. Low-volume block did not result in increased intraocular pressure or other adverse effects at any time point in any treatment group. Statistically significant corneal anesthesia (P < .001) was observed 1 minute after block in all groups, persisting through 4 hours after lidocaine or mepivacaine block and through 24 hours after bupivacaine block. Clinically significant periocular anesthesia was not observed in any group. Significant vertical pupil diameter increase (P < .05) was observed for up to 4 hours after lidocaine or mepivacaine block and 6 hours after bupivacaine block. Low-volume retrobulbar block with any of the 3 local anesthetic drugs evaluated was not associated with adverse effects. In terms of efficacy, mepivacaine block showed no clinical advantage over lidocaine block. However, bupivacaine block induced comparatively rapid and sustained corneal anesthesia. In comparison to published findings using a larger injection volume, low-volume retrobulbar block with lidocaine produced clinically comparable corneal anesthesia. However, periocular soft tissue anesthesia was not achieved with any local anesthetic drug at low volume.

Stimuli-sensitive biomimetic nanoparticles for the inhibition of breast cancer recurrence and pulmonary metastasis

Biomimetic nanoparticles represent a promising avenue for mitigating rapid clearance by the reticuloendothelial system (RES); however, current challenges include insufficient tumour targeting, suboptimal adhesion, and inadequate localized drug release within tumour regions. These shortcomings contribute to persistent contests, such as recurrence and pulmonary metastasis, even with advanced breast cancer therapies. Stimuli-sensitive drug release can furbish the membrane coated nanoparticles for their efficiency against the stated problems. To enhance the efficacy of biomimetic nanoparticles in addressing these issues, we proposed a versatile, stimuli-responsive drug delivery system by encapsulating doxorubicin (Dox) and perfluorohexane (PFH) within poly (lactic-co-glycolic acid) (PLGA) nanoparticles, subsequently coated with macrophage-derived cell membranes. Within this framework, PFH serves as the mediator for ultrasonic (US)-irradiation-triggered drug release specifically within tumour microenvironment, while the macrophage-derived cell membrane coating enhances cell adhesion, enables immune evasion, and natural tumour-homing ability. The characterization assays and in vitro evaluations yielded encouraging results, indicating enhanced targeting and release efficiencies. In vivo studies demonstrated marked inhibitory effects on both breast cancer recurrence and pulmonary metastasis. The resulting data indicate that these engineered nanoparticles have notable potential for targeted delivery and controlled release upon US irradiation, thereby offering significant therapeutic efficacy against primary breast cancer, pulmonary metastasis, and recurrent malignancies. Our findings lay the groundwork for a novel clinical approach, representing an intriguing direction for ongoing investigation by oncologists.

Reevaluating the epinephrine myth: A comprehensive review.

The combination of local anesthetic drugs with epinephrine has conventionally been contraindicated in acral regions due to concerns of potential necrosis caused by compromised blood flow. However, this belief has been challenged since 2001, when studies demonstrated the safety and effectiveness of the combination. This review aims to analyze reported cases of acral area necrosis following the use of local anesthesia with epinephrine since 2001. A thorough search was conducted on PubMed and Google Scholar using specific keywords to identify articles reporting acral area necrosis caused using local anesthesia and epinephrine. Our search yielded eight publications describing a total of 13 cases of ischemic events in acral areas. These cases involved finger necrosis (five cases), scrotal skin necrosis (two cases), and eyelid necrosis (six cases), following the injection of a combination of epinephrine and lignocaine. The majority of affected patients were female who underwent surgical intervention and reconstruction. The use of epinephrine in local anesthesia offers significant advantages and is generally safe for acral areas. However, the risk of necrosis cannot be entirely eliminated, particularly in patients with compromised vascular function. Adhering to proper guidelines and selecting suitable patients can help mitigate the risk. Phentolamine serves as a potential rescue agent if vascular compromise occurs. Precautionary measures must be taken when using this combination in high-risk patients.

Flow of magnetohydrodynamic blood-based hybrid nanofluids with double diffusion in the presence of Riga plate for heat optimization and drug applications

In a recent study, researchers investigated the flow behavior of Casson Hybrid nanofluids (HNFs) combination of single and multi-walled carbon nanotubes (SWCNTs), (MWCNTs) on a Riga plate for drug delivery applications. The study found that the Casson HNFs exhibited non-Newtonian behavior on the Riga plate, with the presence of nanoparticles causing an increase in viscosity and shear-thinning behavior. This rheological behavior is favorable for drug delivery applications as it improves the stability and dispersion of drug particles in the fluid. The similarity equations of the flow problem are easily tackled with the homotopy analysis method (HAM) built on fundamental homotopy mapping. In high-speed flows, Riga actuators are expected to achieve the requirements, since HNF is enhanced by modified Hartmann numbers. As the Eckert number, heat generation/absorption parameter, and thermal relaxation time parameter decrease the temperature, thermal transport increases. Furthermore, with the increments in paramount parameters, the skin friction coefficient and heat transfer rate are remarkably meliorated under higher modified Hartmann number. Furthermore, the study also found that the Casson Hybrid nanofluids showed enhanced heat transfer properties on the Riga plate, which is beneficial for localized drug delivery applications that require precise temperature control.

Impact of Injection-Based Delivery Parameters on Local Distribution Volume of Ethyl-Cellulose Ethanol Gel in Tissue and Tissue Mimicking Phantoms.

Local drug delivery aims to minimize systemic toxicity by preventing off-target effects; however, injection parameters influencing depot formation of injectable gels have yet to be thoroughly studied. We explored the effects of needle characteristics, injection depth, rate, volume, and polymer concentration on gel ethanol distribution in both tissue and phantoms. The polymer ethyl cellulose (EC) was added to ethanol to form an injectable gel to ablate cervical precancer and cancer. Tissue mimicking phantoms composed of 1% agarose dissolved in deionized water were used to establish overall trends between various injection parameters and the resulting gel distribution. Additional experiments were performed in excised swine cervices with a CT-imageable injectate formulation, which enabled visualization of the distribution without tissue sectioning. Needle type and injection rate had minimal impact on gel distribution, while needle depths ≥13 mm yielded significantly larger distributions. Needle gauge and EC concentration impacted injection pressure with maximum gel distribution achieved when the pressure was 70-250 kPa. Injection volumes ≤3 mL of 6% EC-ethanol minimized fluid leakage away from the injection site. Results guided the development of a speculum-compatible hand-held injector to deliver gel ethanol into the cervix. Needle depth, gauge, and polymer concentration are critical to consider when delivering injectable gels. This study addressed key questions related to the impact of injection-based parameters on gel distribution at a scale relevant to human applications including: 1) how best to deliver EC-ethanol into the cervix and 2) general insights about injection protocols relevant to the delivery of injectable gels in tissue.

Signaling switches maintain intercellular communication in the vascular endothelium

The endothelium is a sophisticated coordination center that controls a wide range of vascular functions, which include the regulation of blood pressure and blood flow via changes in vascular contractility. To coordinate vascular function, cell communication and interactions are required for tissue level responses to emerge. A significant form of cell-cell communication occurs by the propagation of Ca2+ signals between cells (‘Ca2+ waves’). The objective of our study was to tease apart the mechanisms driving these intercellular Ca2+ waves in the vascular endothelium. We hypothesised that diffusion of free Ca2+ would drive endothelial Ca2+ wave propagation and effect vessel diameter changes. To investigate the mechanisms, intact mesenteric arteries from male Sprague Dawley rats were mounted in an en face preparation, stained with the Ca2+ indicator Cal-520/AM and were imaged on specialised epifluorescence microscopes. Intercellular endothelial signaling was manipulated using caged compounds in concert with precise spatial and temporal control of UV illumination, as well as global or localized drug application. We show that multiple mechanisms maintain communication so that Ca2+ wave propagation occurs irrespective of the status of cell connectivity. Contrary to our hypothesis, regenerative IP3-induced IP3 production transmits Ca2+ signals between adjoining cells and explains the propagated vasodilation that underlies the increased blood flow accompanying tissue activity. By controlling the production of IP3, the inositide is itself suffcient to evoke a regenerative phospholipase C-dependent Ca2+ wave across coupled cells. None of gap junctions, Ca2+ diffusion nor the release of extracellular messengers are required to support this type of intercellular Ca2+ signaling. Surprisingly, when a discontinuity between cells was created using a fire-polished pipette tip, signal was propagated to the other side of the discontinuity and was able to drive propagated vasodilation. Experiments using counter flow and localised perfusion in the absence and presence of P2Y inhibitors revealed that it is ATP released as a diffusible extracellular messenger that transmits Ca2+ signals across endothelial discontinuities. These results show that signaling switches underlie endothelial cell-cell signal transmission, and reveal how communication is maintained in the face of endothelial damage. The findings provide a new framework for understanding Ca2+ wave propagation and cell-cell signaling in the endothelium. This work was funded by the British Heart Foundation (RG/F/20/110007; PG/20/9/34859 ). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.