Improvement of dermal delivery of tetracycline using vesicular nanostructures

Breaking boundaries: the advancements in transdermal delivery of antibiotics

Transdermal drug delivery systems (TDDS) for antibiotics have seen significant advances in recent years that aimed to improve the efficacy and safety of these drugs. TDDS offer many advantages over other conventional delivery systems such as non-invasiveness, controlled-release pattern, avoidance of first-pass metabolism. The objective of this review is to provide an overview on the recent advances in the TDDS of different groups of antibiotics including β-lactams, tetracyclines, macrolides, and lincosamides, utilized for their effective delivery through the skin and to explore the challenges associated with this field. The majority of antibiotics do not have favorable properties for passive transdermal delivery. Thus, novel strategies have been employed to improve the delivery of antibiotics through the skin, such as the use of nanotechnology (nanoparticles, solid-lipid nanoparticles, nanoemulsions, vesicular carriers, and liposomes) or the physical enhancement techniques like microneedles and ultrasound. In conclusion, the transdermal delivery systems could be a promising method for delivering antibiotics that have the potential to improve patient outcomes and enhance the efficacy of drugs. Further research and development are still needed to explore the potential of delivering more antibiotic drugs by using various transdermal drug delivery approaches.

Kinetic assessment of iontophoretic delivery efficiency of niosomal tetracycline hydrochloride incorporated in electroconductive gel

The purpose of this study was to conduct the kinetic assessment of iontophoretic delivery of niosomal tetracycline-HCl formulated in an electroconductive gel. Tween-80 and Span-80 were used to obtain tetracycline-HCl niosomes with an average diameter of 101.9 ± 3.3 nm, a polydispersity index of 0.247 ± 0.004, a zeta potential of - 34.1 mV, and an entrapment efficiency of 70.08 ± 0.16%. Four different gel preparations, two of which contained niosomal tetracycline-HCl, were transdermally delivered using Franz diffusion cells under the trigger effect of iontophoresis, applied at 0.2, 0.5, and 1 mA/cm2 current density. The control group was the passive diffusion results of the preparation made using a tetracycline-HCl-based drug marketed in Turkey. The control group was compared with the groups that contained (a) tetracycline-HCl in an electroconductive gel, (b) the niosomal tetracycline-HCl formulation in water, and (c) the niosomal tetracycline-HCl formulation in the electroconductive gel. The group with the niosomal formulation in the electroconductive gel displayed the highest increase in iontophoretic transdermal delivery relative to the control group, displaying a 2-, 2.1-, and 2.2-fold increase, respectively, by current density. The experimental results of transdermal delivery using the synergistic effect of niosomal formulation in electroconductive gel and the trigger effect of iontophoresis appeared to divert slightly from zero-order kinetics, demonstrating a statistically significant increase in the rate of controlled transdermal drug delivery. Considering that about 20% of the formulation is transdermally delivered in the first half-hour, the iontophoretic transdermal delivery of niosomal tetracycline-HCl can be efficiently used in local iontophoretic therapy.

Ultrasound-assisted synthesis of MIL-88(Fe) conjugated starch-Fe3O4 nanocomposite: A safe antibacterial carrier for controlled release of tetracycline

A constructing antibiotic carrier with a sustained release profile is a promising method to stop long-term bacterial infection, which is of ideal interest in different biomedical fields. To end this, the present study aims to design a novel carrier based on the modification of biopolymeric starch for the rising possible interaction between carrier and antibiotic agent. We established an in-situ ultrasound-assisted method was applied to grow and create MIL-88(Fe) framework in the structure of magnetic polysaccharide (i.e., St/Fe₃O₄) synthesized by precipitation method resulting in St/Fe₃O₄/MIL-88(Fe) nanocomposite. It was loaded with a high amount of Tetracycline (TC) through its immersion into the TC aqueous solution. The release profile of TC-loaded St/Fe₃O₄/MIL-88(Fe) displays a lower initial burst release (about 26 % after 12 h) and followed by a controlled and sustained release (about 73 % up to 168 h) in the simulated physiological environment at pH 7.4. The in vitro cytotoxicity showed good cytocompatibility against Human skin fibroblast (HFF-1) cells. TC-loaded St/Fe₃O₄/MIL-88(Fe) showed higher antibacterial activity against both S. aureus and E. coli with the MIC value of 64 and 128 μg·mL^-1, respectively.

Topological Optimisation Structure Design for Personalisation of Hydrogel Controlled Drug Delivery System

Personalised controlled drug delivery systems (CDDSs) can adjust drug concentration levels according to patient needs, which has enormous research prospects in precision medicine. In this study, the topological optimisation method was utilised in the structural design of a hydrogel CDDS to achieve a parameter-based adjustment of the drug average concentration in the hydrogel. A polyacrylamide/sodium alginate dual-network hydrogel was selected as a drug carrier, and tetracycline hydrochloride was used as a model drug. The topological optimisation model of the hydrogel CDDS was developed. The effects of the mesh size, target concentration, and volume factor on the optimised results were investigated. Hydrogel flow channel structures were obtained, which satisfied the different target concentrations. To verify the rationality of the optimisation model, in vitro drug release experiments were carried out. The results show that the hydrogel CDDS can control drug release within 7 days, and the drug release tends to follow zero-order release behaviour. The adjustable average concentration of tetracycline hydrochloride in hydrogel CDDS is recommended in the range of 20.79 to 31.04 mol/m³. This novel method provides a reference for personalised structure design of CDDS in the context of precision medicine.

Hydrogel-forming microarray patch mediated transdermal delivery of tetracycline hydrochloride

Antibiotic resistance is one of the most serious health problems today and is expected to worsen in the coming decades. It has been suggested that antibiotic administration routes that bypass the human gut could potentially tackle this problem. In this work, an antibiotic hydrogel-forming microarray patch (HF-MAP) system, which can be used as an alternative antibiotic delivery technology, has been fabricated. Specifically, poly(vinyl alcohol)/poly(vinylpyrrolidone) (PVA/PVP) microarray showed excellent swelling properties with >600% swelling in PBS over 24 h. The tips on the HF-MAP were proven to be able to penetrate a skin model which is thicker than stratum corneum. The antibiotic (tetracycline hydrochloride) drug reservoir was mechanically robust and dissolved completely in an aqueous medium within a few minutes. In vivo animal studies using a Sprague Dawley rat model showed antibiotic administration using HF-MAP achieved a sustained release profile, in comparison with animals receiving oral gavage and intravenous (IV) injection, with a transdermal bioavailability of 19.1% and an oral bioavailability of 33.5%. The maximum drug plasma concentration for HF-MAP group reached 7.40 ± 4.74 μg/mL at 24 h, whereas the drug plasma concentration for both oral (5.86 ± 1.48 μg/mL) and IV (8.86 ± 4.19 μg/mL) groups peaked soon after drug administration and had decreased to below the limit of detection at 24 h. The results demonstrated that antibiotics can be delivered by HF-MAP in a sustained manner.

Chitosan -based nanoniosome for potential wound healing applications: Synergy of controlled drug release and antibacterial activity

This study aims to develop a niosomal platform which can delivery drugs such as tetracycline hydrochloride (TCH) to treat bacterial infections in wounds. To this end, chitosan (CS) was used to obtain a controlled drug release and at the same time antibacterial activity. By design of experiments the niosome encapsulated TCH (TCH-Nio) were optimized for their particle size and encapsulation efficiency, followed by analysis of the release profile of TCH and stability of TCH-Nio and TCH-Nio@CS. The antibacterial activity and cytotoxicity of the fabricated nanoparticles were investigated as well. The release rate of TCH from TCH-Nio@CS in all conditions is less than TCH-Nio. In addition, higher temperature increases the release rate of drug from these formulations. The size, polydispersity index, and encapsulation efficacy of TCH-Nio and TCH-Nio@CS were more stable in 4 °C compared to 25 °C. TCH, TCH-Nio, and TCH-Nio@CS had MIC values of 7.82, 3.91, and 1.95 μg/mL for Escherichia coli, 3.91, 1.95, and 0.98 μg/mL for Pseudomonas aeruginosa, and 1.96, 0.98, and 0.49 μg/mL for Staphylococcus aureus, respectively. Coating of chitosan on niosome encapsulated TCH (TCH-Nio@CS) led to a reduced burst release of TCH from niosome (TCH-Nio), and enabled 2-fold higher antibacterial and anti-biofilm activity against the tested bacterial pathogens E. coli, P. aeruginosa and S. aureus, compared to the uncoated TCH-Nio, and 4-folder higher than the TCH solution, suggesting the synergetic effect of niosome encapsulation and chitosan coating. Moreover, the formulated niosomes displayed no in vitro toxicity toward the human foreskin fibroblast cells (HFF). Both TCH-Nio and TCH-Nio@CS were found to down-regulate the expression of certain biofilm genes, i.e., csgA, ndvB, and icaA in the tested bacteria, which might partially explain the improved antibacterial activity compared to TCH. The obtained results demonstrated that TCH-Nio@CS is capable of controlled drug release, leading to high antibacterial efficacy. The established platform of TCH-Nio@CS enlighten a clinic potential toward the treatment of bacterial infections in skin wounds, dental implants and urinary catheter.

Nanotechnology: a contemporary therapeutic approach in combating infections from multidrug-resistant bacteria

In the 20th century, the discovery of antibiotics played an essential role in the fight against infectious diseases, including meningitis, typhoid fever, pneumonia and Mycobacterium tuberculosis. The development of multidrug resistance in microflora due to improper antibiotic use created significant public health issues. Antibiotic resistance has increased at an alarming rate in the past few decades. Multidrug-resistant bacteria (superbugs) such as methicillin-resistant Staphylococcus aureus (MRSA) as well as drug-resistant tuberculosis pose serious health implications. Despite the continuous increase in resistant microbes, the discovery of novel antibiotics is constrained by the cost and complexities of discovery of drugs. The nanotechnology has given new hope in combating this problem. In the present review, recent developments in therapeutics utilizing nanotechnology for novel antimicrobial drug development are discussed. The nanoparticles of silver, gold and zinc oxide have proved to be efficient antimicrobial agents against multidrug-resistant Klebsiella, Pseudomonas, Escherichia Coli and MRSA. Using nanostructures as carriers for antimicrobial agents provides better bioavailability, less chances of sub-therapeutic drug accumulation and less drug-related toxicity. Nanophotothermal therapy using fullerene and antibody functionalized nanostructures are other strategies that can prove to be helpful.

Nano-Size Characterization and Antifungal Evaluation of Essential Oil Molecules-Loaded Nanoliposomes

Nanoliposomes, bilayer vesicles at the nanoscale, are becoming popular because of their safety, patient compliance, high entrapment efficiency, and prompt action. Several notable biological activities of natural essential oils (EOs), including fungal inhibition, are of supreme interest. As developed, multi-compositional nanoliposomes loaded with various concentrations of clove essential oil (CEO) and tea tree oil (TTO) were thoroughly characterized to gain insight into their nano-size distribution. The present work also aimed to reconnoiter the sustainable synthesis conditions to estimate the efficacy of EOs in bulk and EO-loaded nanoliposomes with multi-functional entities. Following a detailed nano-size characterization of in-house fabricated EO-loaded nanoliposomes, the antifungal efficacy was tested by executing the mycelial growth inhibition (MGI) test using Trichophyton rubrum fungi as a test model. The dynamic light scattering (DLS) profile of as-fabricated EO-loaded nanoliposomes revealed the mean size, polydispersity index (PdI), and zeta potential values as 37.12 ± 1.23 nm, 0.377 ± 0.007, and −36.94 ± 0.36 mV, respectively. The sphere-shaped morphology of CEO and TTO-loaded nanoliposomes was confirmed by a scanning electron microscope (SEM). The existence of characteristic functional bands in all tested counterparts was demonstrated by attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy. Compared to TTO-loaded nanoliposomes, the CEO-loaded nanoliposomes exhibited a maximum entrapment efficacy of 91.57 ± 2.5%. The CEO-loaded nanoliposome fraction, prepared using 1.5 µL/mL concentration, showed the highest MGI of 98.4 ± 0.87% tested against T. rubrum strains compared to the rest of the formulations.

Overcoming hydrolytic degradation challenges in topical delivery: non-aqueous nano-emulsions

INTRODUCTION

Non-aqueous nano-emulsions (NANEs) are colloidal lipid-based dispersions with nano-sized droplets formed by mixing two immiscible phases, none of which happens to be an aqueous phase. Their ability to incorporate water and oxygen sensitive drugs without any susceptibility to degradation makes them the optimum dosage form for such candidates. In NANEs, polar liquids or polyols replace the aqueous phase while surfactants remain same as used in conventional emulsions. They are a part of the nano-emulsion family albeit with substantial difference in composition and application.

AREAS COVERED

The present review provides a brief insight into the strategies of loading water-sensitive drugs into NANEs. Further advancement in these anhydrous systems with the use of solid particulate surfactants in the form of Pickering emulsions is also discussed.

EXPERT OPINION

NANEs offer a unique platform for delivering water-sensitive drugs by loading them in anhydrous formulation. The biggest advantage of NANEs vis-à-vis the other nano-cargos is that they can also be prepared without using equipment-intensive techniques. However, the use of NANEs in drug delivery is quite limited. Looking at the small number of studies available in this direction, a need for further research in this field is required to explore this delivery system further.

Nanotechnology-based formulations toward the improved topical delivery of anti-acne active ingredients

Introduction: Acne vulgaris is a chronic inflammatory skin disorder that affects an extremely concerning percentage of teenagers (ca. 85%), gathering serious negative impacts on the social life and psychological well-being of individuals. Conventional topical formulations for acne show low tolerability and side effects, such as skin irritation, leading to a decrease in the user's adherence to therapy. Nanotechnology-based formulations were developed as new strategies for topical acne management, particularly to overcome the difficulties associated with conventional treatments.Areas covered: This paper presents a critical analysis of reviewed nanosized anti-acne technological strategies, strongly supporting controlled active ingredient release, improved skin permeation, and lower skin irritation. An updated regulatory framework, considering the promising applications in nanomedicine, and the toxicity of these nanosystems are also addressed.Expert opinion: Nanosystems evidence several advantages, attending to the possibility of controlled active ingredient release, better skin permeation, and lower skin irritation. However, novel nanotechnological strategies for acne treatment and care can lead to new side effects, but also environmental nano pollution. Little is known about the toxicology of these nanotechnology-based formulations, therefore, as future trends, more studies should be conducted to assure the consumers' health and environmental safety.

Ultrasound-assisted synthesis of MIL-88(Fe) coordinated to carboxymethyl cellulose fibers: A safe carrier for highly sustained release of tetracycline

For stopping long-time harmful bacterial infection, designing a drug carrier with a highly prolonged release profile is a promising approach that is of interest to different biomedical areas. The subject of this work is to synthesis a novel carrier system through coordination of MIL-88(Fe) to carboxymethyl cellulose (CMC) for enhancing interaction between drug and carrier. We established an ultrasound-assisted synthetic method for in situ synthesis of MIL-88(Fe) in the presence of CMC resulting in CMC/MIL-88(Fe) composite. The CMC/MIL-88(Fe) was loaded with a high amount of Tetracycline (TC) by immersion of carrier to the TC aqueous solution. The release profile in the simulated physiological conditions, pH 7.4, revealed a low initial burst release followed by a sustained and prolonged release over 384 h. The in vitro cytotoxicity of CMC/MIL-88(Fe) against Human skin fibroblast (HFF-1) cells was calculated by MTT assay and showed a good cytocompatibility. The antibacterial activity was found for TC-loaded CMC/MIL-88(Fe) toward both E. coli and S. aureus with MIC 64 mg·ml^-1.

Insight Into Nanoliposomes as Smart Nanocarriers for Greening the Twenty-First Century Biomedical Settings

The necessity to develop more efficient, biocompatible, patient compliance, and safer treatments in biomedical settings is receiving special attention using nanotechnology as a potential platform to design new drug delivery systems (DDS). Despite the broad range of nanocarrier systems in drug delivery, lack of biocompatibility, poor penetration, low entrapment efficiency, and toxicity are significant challenges that remain to address. Such practices are even more demanding when bioactive agents are intended to be loaded on a nanocarrier system, especially for topical treatment purposes. For the aforesaid reasons, the search for more efficient nano-vesicular systems, such as nanoliposomes, with a high biocompatibility index and controlled releases has increased considerably in the past few decades. Owing to the stratum corneum layer barrier of the skin, the in-practice conventional/conformist drug delivery methods are inefficient, and the effect of the administered therapeutic cues is limited. The current advancement at the nanoscale has transformed the drug delivery sector. Nanoliposomes, as robust nanocarriers, are becoming popular for biomedical applications because of safety, patient compliance, and quick action. Herein, we reviewed state-of-the-art nanoliposomes as a smart and sophisticated drug delivery approach. Following a brief introduction, the drug delivery mechanism of nanoliposomes is discussed with suitable examples for the treatment of numerous diseases with a brief emphasis on fungal infections. The latter half of the work is focused on the applied perspective and clinical translation of nanoliposomes. Furthermore, a detailed overview of clinical applications and future perspectives has been included in this review.

Nanocarriers for treatment of dermatological diseases: Principle, perspective and practices

Skin diseases are the fourth leading non-fatal skin conditions that act as a burden and affect the world economy globally. This condition affects the quality of a patient's life and has a pronounced impact on both their physical and mental state. Treatment of these skin conditions with conventional approaches shows a lack of efficacy, long treatment duration, recurrence of conditions, systemic side effects, etc., due to improper drug delivery. However, these pitfalls can be overcome with the applications of nanomedicine-based approaches that provide efficient site-specific drug delivery at the target site. These nanomedicine-based strategies are evolved as potential treatment opportunities in the form of nanocarriers such as polymeric and lipidic nanocarriers, nanoemulsions along with emerging others viz. carbon nanotubes for dermatological treatment. The current review focuses on challenges faced by the existing conventional treatments along with the topical therapeutic perspective of nanocarriers in treating various skin diseases. A total of 213 articles have been reviewed and the application of different nanocarriers in treating various skin diseases has been explained in detail through case studies of previously published research works. The toxicity related aspects of nanocarriers are also discussed.

Microscopic Investigation of the Combined Use of Antibiotics and Biosurfactants on Methicillin Resistant Staphylococcus aureus

One current strategy to deal with the serious issue of antibiotic resistance is to use biosurfactants, weak antimicrobials in their own right, with antibiotics in order to extend the efficacy of antibiotics. Although an adjuvant effect has been observed, the underlying mechanisms are poorly understood. To investigate the nature of the antibiotic and biosurfactant interaction, we undertook a scanning electron microscopy (SEM) and atomic force microscopy (AFM) microscopic study of the effects of the tetracycline antibiotic, combined with sophorolipid and rhamnolipid biosurfactants, on Methicillin-resistant Staphylococcus aureus using tetracycline concentrations below and above the minimum inhibitory concentration (MIC). Control and treated bacterial samples were prepared with an immersion technique by adsorbing the bacteria onto glass substrates grafted with the poly-cationic polymer polyethyleneimine. Bacterial surface morphology, hydrophobic and hydrophilic surface characters as well as the local bacterial cell stiffness were measured following combined antibiotic and biosurfactant treatment. The sophorolipid biosurfactant stands alone insofar as, when used with the antibiotic at sub-MIC concentration, it resulted in bacterial morphological changes, larger diameters (from 758 ± 75 to 1276 ± 220 nm, p-value = 10^-4) as well as increased bacterial core stiffness (from 205 ± 46 to 396 ± 66 mN/m, p-value = 5 × 10^-5). This investigation demonstrates that such combination of microscopic analysis can give useful information which could complement biological assays to understand the mechanisms of synergy between antibiotics and bioactive molecules such as biosurfactants.

A brief overview on nano-sized materials used in the topical treatment of skin and soft tissue bacterial infections

Introduction: Skin and soft tissue infections are a significant clinical problem that can happen anywhere on the body. Bacteria are the most common cause of skin and soft tissue infections in humans. Despite the fact that there is a lot of antimicrobial agents and antibiotics for elucidating bacterial infections, the prevention and control of infectious diseases continue to be one of the greatest challenges for public health worldwide. At the present time, an alarming increase in multidrug resistance instantly requests to find suitable alternatives to current antibiotics. Therefore, drug resistance has been attempted to be resolved by the development of new classes of antimicrobial agents or targeted delivery systems for antibacterial drugs using nanotechnology.Area covered: The present review summarizes the emerging topical efforts to support the use of nano-sized materials as a new opportunity to combat today's skin infectious diseases.Expert opinion: Nano-sized materials can overcome the stratum corneum barrier and deliver drugs specifically to bacterial skin infections with trivial side effects. Depending on the physicochemical characteristics of nano-scaled materials, they can specifically be selected to target bacterial pathogens and also to get into the skin layers. These systems can overcome the antibiotic-resistance mechanisms and help us to the design of novel topical formulations that will make administration of antibacterial compounds safer, easier and more convenient.

Liposome-based combination therapy for acne treatment

Acne vulgaris is one of the most common chronic diseases worldwide with the high prevalence ratio of about 80-85% in patients who are in puberty period. For the treatment options, many conventional dosage forms are available; however, existing limitations of systemic administration of drugs (oral antibiotics), such as adverse events and resistance, led for seek of new formulation options. In this study, liposomes containing tetracycline HCl and tretinoin were prepared by the film formation method. In vitro characterization studies revealed that liposomes (111.10 ± 8.02 nm; P.D.I.=0.198 ± 0.03; Z.P.=25.83 ± 0.40 mV) with an encapsulation efficiency more than 80% for both APIs were formulated. In order to maintain a suitable viscosity for topical application, optimized liposomal formulations were dispersed in carbopol-based gel. In vitro release of APIs was sustained for 24 hours with released amounts of 56.44% and 58.44% for tetracycline HCl and tretinoin, respectively. Stability evaluation of both liposomes and liposomes in hydrogels was investigated for 6 months at 4 °C and 25 °C; and no statistically significant change was observed in terms of particle size, zeta potential, encapsulation efficiency, appearance, pH, and viscosity. Cytotoxicity tests confirmed the nontoxic structure of liposomal gel formulations on mice fibroblast cells. In addition, antibacterial efficacy has been proven with Staphylococcus aureus and Streptococcus epidermidis strains as well as the effect on biofilm formation and eradication. As a result, we hereby presented a new combination drug product, which consists of dual active ingredients having comedolytic and bacteriostatic effects in a single, safe, and stable liposome formulation.

Freeze-thaw-induced cross-linked PVA/chitosan for oxytetracycline-loaded wound dressing: the experimental design and optimization

Oxytetracycline is an antibiotic for the treatment of the infections caused by Gram-positive and Gram-negative microorganisms. Among novel formulations applied for damaged skin, hydrogels have shown to be superior as they can provide a moist environment for the wound. The purpose of this study was to prepare and evaluate the hydrogels of oxytetracycline consisted of polyvinyl alcohol (PVA) and chitosan polymers. A study design based on 4 factors and 3 levels was used for the preparation and evaluation of hydrogels formed by freeze-thaw (F-T) cycle using PVA and chitosan as a matrix-based wound dressing system. Furthermore, an experimental design was employed in order to study the effect of independent variables, namely drug amount (X₁, 500-1000 mg), the amount of PVA (X₂, 3.33-7.5%), the amount of chitosan (X₃, 0.5-1%), and F-T cycle (X₄, 3-7 cycles) on the dependent variables, including encapsulation efficiency, swelling index, adsorption of protein onto hydrogel surface, and skin permeation. The interaction of formulation variables had a significant effect on both physicochemical properties and permeation. Hydrogel microbial tests with sequential dilution method in Muller-Hinton broth medium were also carried out. The selected hydrogel (F6) containing 5% PVA, 0.75% chitosan, 1000 mg drug, and 3 F-T cycles was found to have increased encapsulation efficiency, gel strength, and higher skin permeation suitable for faster healing of wounds. Results showed the biological stability of oxytetracycline HCl in the hydrogel formulation with a lower dilution of the pure drug. Thus, oxytetracycline-loaded hydrogel could be a potential candidate to be used as a wound dressing system.