Docetaxel Liposomes - A formulation Screening Study

Docetaxel (DOC) is a potent anticancer drug with several limitations, including poor solubility and the reported serious side effects, attributed to either the drug itself or the solvent used. Thus, it is interesting to entrap the drug into liposomes in order to solubilize the drug and improve the therapeutic outcome. The fist aim of this study was to establish a small-scale screening method for preparing and characterizing DOC-liposomes. Secondly, the established methods were applied to investigate the effect of lipid composition on the liposomal drug entrapment

The Expanded Role of Chitosan in Localized Antimicrobial Therapy

Chitosan is one of the most studied natural origin polymers for biomedical applications. This review focuses on the potential of chitosan in localized antimicrobial therapy to address the challenges of current rising antimicrobial resistance. Due to its mucoadhesiveness, chitosan offers the opportunity to prolong the formulation residence time at mucosal sites; its wound healing properties open possibilities to utilize chitosan as wound dressings with multitargeted activities and more. We provide an unbiased overview of the state-of-the-art chitosan-based delivery systems categorized by the administration site, addressing the site-related challenges and evaluating the representative formulations. Specifically, we offer an in-depth analysis of the current challenges of the chitosan-based novel delivery systems for skin and vaginal infections, including its formulations optimizations and limitations. A brief overview of chitosan’s potential in treating ocular, buccal and dental, and nasal infections is included. We close the review with remarks on toxicity issues and remaining challenges and perspectives

Electrospinning of chloramphenicol-containing nanofibrous dressings for treatment of chronic wounds

Background An efficient treatment is crucial to overcome the delayed healing process and high infection rate in chronic wounds. Nanofibrous dressings, having a nano‐sized fiber structure, can enhance cell ingrowth and support the healing process. In addition, nanofibers can deliver active ingredients e.g. antibiotics into the wound to treat wound infection. By incorporating broad‐spectrum antibiotics like chloramphenicol into a nanofibrous dressing, wound infection can be treated whereas systemic side effects are avoided. Active nanofiberforming polymers can be added to achieve more functionalities. Examples are the β‐glucan‐ and chitosan polymers, with their immunostimulating and antimicrobial properties, respectively. Combining these polymers in one dressing might provide a multifunctional and more efficient wound dressing. Goals The goal of this project is to electrospin a multifunctional dressing comprising the active polymers β‐glucan and chitosan. For this, we investigated the effect of the different active ingredients on nanofiber characteristics such as morphology, diameter, swelling index and cytotoxicity. Methods Nanofibers were spun from preformed polymer‐solutions using the needle‐free NanospiderTM technology. Nanofiber morphology and diameter were determined by SEM and the image‐processing program ImageJ. The thickness was measured using a micrometer and swelling index was determined by submerging the nanofibers into artificial wound fluid. Cytotoxicity of the nanofibers was tested using the Cell Counting Kit‐8 (Sigma‐Aldrich). Results and Conclusion Nanofibers comprising 20% chitosan and 20% βG together with the copolymers polyethylene oxide and hydroxypropylmethylcellulose and 1% chloramphenicol were successfully fabricated. All fibers had a randomly distributed fiber structure with a diameter around 100 nm. Nanofibers containing chitosan had a reduced thickness with values from 0.03 mm to 0.05 mm, compared to fibers without chitosan that had a thickness from 0.06 mm to 0.08 mm, but an improved stability upon contact with water. In addition, chitosan containing nanofibers showed a high swelling index, ranging from 700 to 1200 %. Fibers without chitosan disintegrated upon contact with water, the swelling index could therefore not be measured. All fibers showed no cytotoxicity compared to medium as control when tested on human keratinocytes. The incorporation of chloramphenicol neither influenced the fiber morphology nor the swelling index or cytotoxicity, proving that the design of nanofibers containing both active polymers together with chloramphenicol was successful

Liposomes-in-chitosan hydrogel boosts potential of chlorhexidine in biofilm eradication in vitro

Successful treatment of skin infections requires eradication of biofilms found in up to 90 % of all chronic wounds, causing delayed healing and increased morbidity. We hypothesized that chitosan hydrogel boosts the activity of liposomally-associated membrane active antimicrobials (MAA) and could potentially improve bacterial and biofilm eradication. Therefore, liposomes (∼300 nm) bearing chlorhexidine (CHX; ∼50 μg/mg lipid) as a model MAA were incorporated into chitosan hydrogel. The novel CHX-liposomes-in-hydrogel formulation was optimized for skin therapy. It significantly inhibited the production of nitric oxide (NO) in lipopolysaccharide (LPS)-induced macrophage and almost completely reduced biofilm formation. Moreover, it reduced Staphylococcus aureus and Pseudomonas aeruginosa adherent bacterial cells in biofilm by 64.2–98.1 %. Chitosan hydrogel boosted the anti-inflammatory and antimicrobial properties of CHX

Chitosan-based delivery system enhances antimicrobial activity of chlorhexidine

Infected chronic skin wounds and other skin infections are increasingly putting pressure on the health care providers and patients. The pressure is especially concerning due to the rise of antimicrobial resistance and biofilm-producing bacteria that further impair treatment success. Therefore, innovative strategies for wound healing and bacterial eradication are urgently needed; utilization of materials with inherent biological properties could offer a potential solution. Chitosan is one of the most frequently used polymers in delivery systems. This bioactive polymer is often regarded as an attractive constituent in delivery systems due to its inherent antimicrobial, anti-inflammatory, anti-oxidative, and wound healing properties. However, lipid-based vesicles and liposomes are generally considered more suitable as delivery systems for skin due to their ability to interact with the skin structure and provide prolonged release, protect the antimicrobial compound, and allow high local concentrations at the infected site. To take advantage of the beneficial attributes of the lipid-based vesicles and chitosan, these components can be combined into chitosan-containing liposomes or chitosomes and chitosan-coated liposomes. These systems have previously been investigated for use in wound therapy; however, their potential in infected wounds is not fully investigated. In this study, we aimed to investigate whether both the chitosan-containing and chitosan-coated liposomes tailored for infected wounds could improve the antimicrobial activity of the membrane-active antimicrobial chlorhexidine, while assuring both the anti-inflammatory activity and cell compatibility. Chlorhexidine was incorporated into three different vesicles, namely plain (chitosan-free), chitosan-containing and chitosan-coated liposomes that were optimized for skin wounds. Their release profile, antimicrobial activities, anti-inflammatory properties, and cell compatibility were assessed in vitro. The vesicles comprising chitosan demonstrated slower release rate of chlorhexidine and high cell compatibility. Additionally, the inflammatory responses in murine macrophages treated with these vesicles were reduced by about 60% compared to non-treated cells. Finally, liposomes containing both chitosan and chlorhexidine demonstrated the strongest antibacterial effect against Staphylococcus aureus. Both chitosan-containing and chitosan-coated liposomes comprising chlorhexidine could serve as excellent platforms for the delivery of membrane-active antimicrobials to infected wounds as confirmed by improved antimicrobial performance of chlorhexidine

Characterization of Liposomes Using Quantitative Phase Microscopy (QPM)

The rapid development of nanomedicine and drug delivery systems calls for new and effective characterization techniques that can accurately characterize both the properties and the behavior of nanosystems. Standard methods such as dynamic light scattering (DLS) and fluorescent-based assays present challenges in terms of system’s instability, machine sensitivity, and loss of tracking ability, among others. In this study, we explore some of the downsides of batch-mode analyses and fluorescent labeling, while introducing quantitative phase microscopy (QPM) as a label-free complimentary characterization technique. Liposomes were used as a model nanocarrier for their therapeutic relevance and structural versatility. A successful immobilization of liposomes in a non-dried setup allowed for static imaging conditions in an off-axis phase microscope. Image reconstruction was then performed with a phase-shifting algorithm providing high spatial resolution. Our results show the potential of QPM to localize subdiffraction-limited liposomes, estimate their size, and track their integrity over time. Moreover, QPM full-field-of-view images enable the estimation of a single-particle-based size distribution, providing an alternative to the batch mode approach. QPM thus overcomes some of the drawbacks of the conventional methods, serving as a relevant complimentary technique in the characterization of nanosystems

Deformable liposomes for skin therapy with human epidermal growth factor: The effect of liposomal surface charge

Accepted manuscript version, licensed CC BY-NC-ND 4.0. Published version available at https://doi.org/10.1016/j.ejps.2018.10.005.The topical administration of exogenous human epidermal growth factor (hEGF) is a promising approach for improved chronic wound therapy. To develop therapeutically superior hEGF formulation, we prepared hEGF-containing neutral (NDLs), cationic (CDLs) and anionic (ADLs) deformable liposomes (DLs), respectively, since it is expected that the liposomal surface charge can affect both the liposomal physicochemical properties, their skin penetration potential and therapeutic efficacy of liposome-associated drug. All prepared liposomes were of similar size (300–350 nm) with high hEGF load (~80% entrapment efficacy). Among the studied DLs, ADLs were found to be most promising for sustained release of hEGF, as assessed in vitro using the polyamide membrane. Ex vivo studies revealed that all DLs were excellent systems for skin therapy with hEGF and no penetration of hEGF through the full thickness human skin was detected. ADLs provided a depot exhibiting the highest hEGF retention onto the human skin surface. ADLs also revealed enhanced mitogenic activities in human fibroblasts compared to both NDLs and CDLs after 48 hrs treatment. Moreover, hEGF-containing ADLs significantly enhanced mitogenic activity in fibroblast as compared to activity of hEGF solution (positive control). Similar trends were observed in human keratinocytes after 24 hrs of treatment. We proved that the liposomal surface charge affects the therapeutic potential of hEGF-containing liposomes. hEGF-containing ADLs can be a promising nanosystem-based formulation for localized therapy of chronic wounds

A new preparation method for preparation of liposomes-in-hydrogels primed for treatment of skin diseases

Poster presented at the Liposome Research Days 2014: Living Innovation, at the Technical University of Denmark, Copenhagen, 4-7 August 2014Liposomes are spherical vesicles that form spontaneously when phospholipids are dispersed in an aqueous medium. However, to get liposomes with a more unimodal size distribution, liposomes are usually processed further to reduced size and lammellarity, typically by extrusion, sonication or homogenization. Liposome formulations for topical application needs a vehicle to assure the desirable retention and adhesion of the drug-loaded liposomes onto the skin, and for this, hydrogels are regarded as promising systems. The hydrogel “soluble beta-glucan” (SBG) has caught our attention since it also promotes wound healing on its own. Dual asymmetric centrifuge (DAC) utilizes a unique combination of two contra rotating movements of the sample-holder, which results in shear forces that efficiently homogenize and gives a size reduction of liposomes. We have investigated the use of DAC for both use in liposome size reduction and for further mixing of liposomes into hydrogels

The isolated perfused human skin flap model: A missing link in skin penetration studies?

Manuscript. Published version available in http://dx.doi.org/10.1016/j.ejps.2016.10.003 Development of effective (trans)dermal drug delivery systems requires reliable skinmodels to evaluate skin drug penetration. The isolated perfused human skin flap remainsmetabolically active tissue for up to 6 h during in vitro perfusion. We introduce the isolated perfused human skin flap as a close-to-in vivo skin penetration model. To validate the model's ability to evaluate skin drug penetration the solutions of a hydrophilic (calcein) and a lipophilic (rhodamine) fluorescence marker were applied. The skin flaps were perfused with modified Krebs- Henseleit buffer (pH 7.4). Infrared technology was used to monitor perfusion and to select a well-perfused skin area for administration of the markers. Flap perfusion and physiological parameters were maintained constant during the 6 h experiments and the amount of markers in the perfusate was determined. Calcein was detected in the perfusate, whereas rhodamine was not detectable. Confocal images of skin cross-sections shoved that calcein was uniformly distributed through the skin, whereas rhodamine accumulated in the stratum corneum. For comparison, the penetration of both markers was evaluated on ex vivo human skin, pig skin and cellophanemembrane. The proposed perfused flapmodel enabled us to distinguish between the penetrations of the two markers and could be a promising close-to-in vivo tool in skin penetration studies and optimization of formulations destined for skin administratio

Successful co-encapsulation of benzoyl peroxide and chloramphenicol in liposomes by a novel manufacturing method - dual asymmetric centrifugation

Accepted manuscript version. Published version available at http://dx.doi.org/10.1016/j.ejps.2016.11.017 Encapsulation of more than one active pharmaceutical ingredient into nanocarriers such as liposomes is an attractive approach to achieve a synergic drug effect and less complicated dosing schedules in multi-drug treatment regimes. Liposomal drug delivery in acne treatment may improve drug efficiency by targeted delivery to pilosebaceous units, reduce adverse effects and improve patient compliance. We therefore aimed to co-encapsulate benzoyl peroxide (BPO) and chloramphenicol (CAM) into liposomes using the novel liposome processing method – dual asymmetric centrifugation (DAC). Liposomes were formed from soybean lecithin, propylene glycol and distilled water (2:1:2 w/v/v ratio), forming a viscous liposome dispersion. Liposomes containing both drugs (BPO-CAM-Lip), single-drug (BPO-Lip and CAM-Lip), and empty liposomes were prepared. Drug entrapment of BPO and CAM was determined by a newly developed HPLC method for simultaneous detection and quantification of both drugs. Encapsulation of around 50% for BPO and 60% for CAM respectively was obtained in both single- drug encapsulated formulations (BPO-Lip and CAM-Lip) and co-encapsulated formulations (BPO- CAM-Lip). Liposome sizes were comparable for all liposome formulations, ranging from 130 to 150 nm mean diameter, with a polydispersity index < 0.2 for all formulations. CAM exhibited a sustained release from all liposomal formulations, whereas BPO appeared retained within the liposomes. BPO retention could be attributed to its poor solubility. However, HaCaT cell toxicity was found dependent on BPO released from the liposomes. In the higher concentration range (4% v/v), liposomal formulations were less cytotoxic than the corresponding drug solutions used as reference. We have demonstrated that DAC is a fast, easy, suitable method for encapsulation of more than one drug within the same liposomes