Mupirocin calcium microencapsulation via spray drying: feed solvent influence on microparticle properties, stability and antimicrobial activity

Optimization, Characterization and In Vivo Evaluation of Mupirocin Nanocrystals for Topical Administration

Treatment of infectious skin conditions resulting from wounds and burns with topical antibiotics is challenging, particularly those caused by methicillin-resistant Staphylococcus aureus bacteria (MRSA). This is due to the formation of bacterial biofilms characterized by antimicrobial resistance. Mupirocin (MP), a widely used topical antibiotic, is active against gram-positive bacteria including MRSA. However, MP suffers from sub-optimal therapeutic efficacy due to its poor water-solubility and the significant rise in MP-resistant S. aureus. In this study, the physico-chemical characteristics of MP were modified through nanocrystallization to improve its therapeutic efficacy for the treatment of skin infections. Mupirocin-nanocrystals (MP-NC) were prepared using a nanoprecipitation technique and optimized using a D-optimal response surface design. The optimization of MP-NC produced ultra-small monodisperse spherical particles with a mean diameter of 70 nm and a polydispersity index of 0.2. The design resulted in two optimal MP-NC formulations that were evaluated by performing series of in vitro, ex vivo, microbiological, and in vivo studies. In-vitro results showed a 10-fold increase in the saturation solubility and a 9-fold increase in the dissolution rate of MP-NC. Ex vivo permeation studies, using pig ears skin, showed a 2-fold increase in the dermal deposition of MP-NC with the highest drug deposition occurring at 500-µm skin depth. Moreover, the optimal MP-NC formulations were lyophilized and incorporated into a 2% w/w cream. Microbiological studies revealed a 16-fold decrease in the minimum inhibitory concentration and the minimum bactericidal concentration of MP-NC. In vivo studies, using a rat excision burn wound model, demonstrated rapid and complete healing of infected burn wounds in rats treated with MP-NC cream in comparison to marketed Avoban ointment. Our results suggest that nanocrystallization of MP may provide an avenue through which higher levels of a topically applied MP can be permeated into the skin to reach relevant infectious areas and exert potential local antibacterial effects.

Biological fabrication and electrostatic attractions of new layered silver/talc nanocomposite using Lawsonia inermis L. and its chitosan-capped inorganic/organic hybrid: Investigation on acceleration of Staphylococcus aureus and Pseudomonas aeruginosa infected wound healing

In the present study, new-layered inorganic/organic hybrid of silver/talc nanocomposites (Ag/Tlc-NPs) and its chitosan-capped derivative (Ag/Tlc/Csn NCs) were biochemically synthesized utilizing Lawsonia inermis L. extract. The silver nanoparticles (Ag NPs) were synthesized employing green method on the exterior surface layer of talc mineral as a solid substrate. The negatively charged surface layer of talc might function as templates and can attract the chitosan cations from a solution to yield a layered hybrid structure, whose inorganic phase is formed by Si-O-Ag bonds. Our results revealed that Ag NPs were formed on the exterior surface of talc with a diameter with size of 124-215 nm. In addition, cytotoxicity, in vitro antibacterial activity, and clinical effects of wound-healing ointments containing talc were investigated. The results implied the successful synthesis of Ag/Tlc/Csn NCs using the extract. The structures were safe up to 0.50 mg/mL. In vitro studies confirmed antioxidant and antibacterial properties of Ag/Tlc/Csn NCs. In sum, our findings showed that the ointments improve wound healing process by inducing an anti-inflammatory M2 phenotype and bFGF, CD206, collagen1A, and IL-10 production that causes fibroblast migration and wound closure through influencing M2 macrophage. Ag/Tlc/Csn is suggested to be taken into consideration as a medical combination for improving infected wound healing and as a promising agent for clinical administration.

Effectiveness of Green Synthesis of Silver/Kaolinite Nanocomposite Using Quercus infectoria Galls Aqueous Extract and Its Chitosan-Capped Derivative on the Healing of Infected Wound

Kaolinite nanocomposites (NCs) could be utilized as agents for wound healing owing to their efficiency and low toxicity. The present study was conducted to synthesize a novel silver/kaolinite NCs (Ag/Kaol NCs) and investigate their chitosan derivation (Ag/Kaol/Chit NCs) using oak extract. XRD, SEM, EDX, FT-IR, and DLS were employed for the investigation of structural and physio-chemical properties of the synthesized NCs. The obtained results revealed that synthesized Ag/Kaol NCs were mesoporous and spherical with sizes ranging from 7-11 nm. They also demonstrated successful synthesis between silver and kaolinite using the extract. Cytotoxicity and in vitro antibacterial activity were also investigated. The clinical effects of ointments containing the NCs for improving wound healing were studied on the wound area, total bacterial count, histological parameters, and protein expression of some genes. Nanocomposites were safe up to 0.50 mg/mL. The results of in vivo and in vitro antibacterial activity showed that Ag/Kaol NCs, were of antibacterial activity ( ). The results of antioxidant activity indicated that Ag/Kaol NCs have antioxidant structures. Our findings concerning molecular mechanism implied that Ag/Kaol/Chit increased the expression of Wnt/ β -catenin and collagen ( ). In sum, Ag/Kaol/Chit showed antibacterial activity and improved wound healing by decreasing the inflammation and promoting the proliferative phase. The novel NCs showed wound healing properties by decreasing inflammation and total bacterial count and increasing proliferative phase. The application of Ag/Kaol/Chit was suggested as a green agent for improving infected wound healing.

The biological synthesis of gold/perlite nanocomposite using Urtica dioica extract and its chitosan-capped derivative for healing wounds infected with methicillin-resistant Staphylococcus aureus

The preparation of ointments from natural compounds is essential for accelerating infected wounds. This study investigated the effects of topical uses of gold nanoparticles (Au)/perlite (Au/Perl) nanocomposites (NCs) by the help of Urtica dioica extract and its chitosan-capped derivative (Chit) on methicillin-resistant Staphylococcus aureus (MRSA)-infected wound healing in a mouse model. Furthermore, Au/Perl/Chit nanocomposite was prepared using protonated chitosan solution. The physicochemical properties of the as-synthesized nanocomposites were also investigated. The effects of Au/Perl/Chit NC were assessed by antibacterial, histopathological parameters as well as molecular evaluations. Then, they were compared with synthetic agent of mupirocin. The results revealed that Au/Perl NC was mesoporous and spherical in a range of 13-15 nm. Topical administration of Au/Perl/Chit ointment accelerated wound healing by reducing bacteria colonization and wound rate enhancing collagen biosynthesis and re-epithelialization, the expressions of IL-10, PI3K, AKT, bFGF, and COL1A genes, which is in agreement with the obtained results for mupirocin. In conclusion, the results strongly demonstrated that administration of ointments prepared from Au/Perl and Au/Perl/Chit nanocomposites stimulates MRSA-infected wound healing by decreasing the length of healing time and regulating PI3K/AKT/bFGF signaling pathway and is a promising candidate in stimulating MRSA-infected wound regeneration.

Polycaprolactone nanofiber coated with chitosan and Gamma oryzanol functionalized as a novel wound dressing for healing infected wounds

This study was conducted to design and evaluate a wound dressing based on a polycaprolactone (PCL) nanofiber coated with gamma oryzanol (GO) and chitosan (CS) in mice model. All the dressings were prepared by electrospinning method, and their morphology and physical properties were investigated. The mice were divided into five groups and treated with I) PCL-sole (PCL), III) PCL-mupirocin (PCL-M), IV) PCL-GO, IV) PCL-CS, and V) PCL-CS-GO. Wound area, total bacterial count, histopathological parameters, and expressions of IL-1β, TNF-α, IL-10, MMP-9, EGF, and VEGF were assessed. The fibers were randomly distributed in PCL group, but loading CS and GO increased the complexity and placing on the dressings. PCLs loaded with GO and CS showed lower viscosity, surface tension, and fiber diameter and higher conductivity and water contact angle compared to unloaded PCLs (P < 0.05). The treatment with PCLs loaded with mupirocin, CS, and GO significantly reduced wound area and total bacterial count (P < 0.05). Loading PCLs with mupirocin, CS, and GO decreased the expressions of IL-1β, TNF-α, MMP-9, but increased the expressions of IL-10 and VEGF compared to the unloaded PCL group (P < 0.05). The most optimal responses to wound healing and physical parameters belonged to the PCL-CS-GO group.

Development, characterisation and nasal deposition of melatonin-loaded pectin/hypromellose microspheres

In this study, we present the development of spray-dried pectin/hypromellose microspheres as efficient melatonin carrier for targeted nasal delivery. Different pectin to hypromellose weight ratios in the spray-dried feed were employed (i.e. 1:0, 3:1, 1:1 and 1:3) in order to optimise microsphere physicochemical properties influencing overall powder behaviour prior, during and upon nasal delivery. All microspheres assured complete melatonin entrapment and increased dissolution rate in relation to pure melatonin powder. Among all combinations tested, combining pectin with hypromellose at 1:3 wt ratio resulted in the microspheres with the highest potential for melatonin nasal delivery as they assured highest swelling ability and most prominent mucoadhesive properties. Studies on deposition profile revealed adequate turbinate and olfactory deposition of microsphere/lactose monohydrate powder blend administered nasally using MIAT® device, complementing findings relevant for their therapeutic potential. In conclusion, developed microspheres bear the potential to ensure prolonged melatonin retention at the nasal mucosa, improved bioavailability and advanced therapeutic outcome.

Electrospun PCL/mupirocin and chitosan/lidocaine hydrochloride multifunctional double layer nanofibrous scaffolds for wound dressing applications

Background

An ideal wound dressing should exhibit good biocompatibility, minimize pain and infection, absorb excess exudates, and maintain a moist environment. However, few clinical products meet all these needs. Therefore, the aim of this study was to fabricate a multifunctional double layer nanofibrous scaffolds (DLS) as a potential material for wound dressing.

Materials and methods

The scaffold was formed from mupirocin and lidocaine hydrochloride homogeneously incorporated into polycaprolactone as the first layer of scaffolds and chitosan as the second layer of scaffolds nanofibers through electrospinning. The fabricated nanofibrous scaffolds were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and measurement of swelling ratio, contact angle, drug release, and mechanical properties. Furthermore, antibacterial assessment, live/dead cell assays, and MTT assays were used to investigate the antibacterial activity and cytotoxicity of the nanofibrous scaffolds.

Results

The morphology of the nanofibrous scaffolds was studied by scanning electron microscopy, showing successful nanofibrous scaffolds. Fourier transform infrared spectroscopy demonstrated the successful incorporation of the material used to produce the produced nanofibrous scaffolds. Thermal studies with thermogravimetric analysis and differential scanning calorimetry indicated that the DLS had high thermal stability. The DLS also showed good in vitro characteristics in terms of improved swelling ratio and contact angle. The mechanical results revealed that the DLS had an improved tensile strength of 3.88 MPa compared with the second layer of scaffold (2.81 MPa). The release of drugs from the scaffold showed different profiles for the two drugs. Lidocaine hydrochlo ride exhibited an initial burst release (66% release within an hour); however, mupirocin exhibited only a 5% release. Furthermore, the DLS nanofibers displayed highly effective antibacterial activities against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa and were nontoxic to fibroblasts.

Conclusion

The fabricated DLS exhibited excellent hydrophilicity, cytocompatibility, sustained drug release, and antibacterial activity, which are favorable qualities for its use as a multifunctional material for wound dressing applications.

Development and validation of an in vitro release method for topical particulate delivery systems

The aim of this study was to develop an in vitro release method for topical particulate delivery systems using the immersion cell in combination with paddle dissolution apparatus. Chitosan- and methacrylate-based microparticles with mupirocin were prepared and used as model topical delivery systems for method development. Diffusion of the drug occurred across a mixed cellulose ester membrane, which demonstrated low drug adsorption and low diffusional resistance. After an initial lag phase the amount of drug released became proportional to the square root of time. The method was discriminative toward differences in formulation, as well as toward differences in drug concentration inside the sample compartment. The method was further used to confirm sameness between batches of the same composition prepared by the same process. Variations in paddle rotation speed (25 rpm, 50 rpm, 100 rpm), paddle height (1cm, 2.5 cm) and volume of release medium (100ml, 200 ml) did not significantly alter the release rates. The method of analysis was validated according to ICH guidelines. Currently there are no compendial or standard methods and apparatuses for in vitro release testing of topical microparticles. The developed method can be a useful guide in formulation development of such delivery systems.

Selection of excipient, solvent and packaging to optimize the performance of spray-dried formulations: case example fenofibrate

CONTEXT

Along with other options, solid dispersions prepared by spray drying offer the possibility of formulating poorly soluble drugs in a rapidly dissolving format. As a wide range of potential excipients and solvents is available for spray drying, it is usually necessary to carry out a comprehensive array of studies to arrive at an optimal formulation.

OBJECTIVE

To study the influence of formulation parameters such as co-sprayed excipients, solvents and packaging on the manufacture, in vitro performance and stability of spray-dried oral drug products using fenofibrate as a model drug.

MATERIALS AND METHODS

Solid dispersions of fenofibrate with different amorphous polymers were manufactured from two solvent systems by spray drying. These were characterized in terms of physicochemical properties, crystalline content and dissolution behavior in biorelevant media upon production and after storage in two packaging systems (Glass and Activ-Vials(™)).

RESULTS AND DISCUSSION

Spray drying the same formulation from two different solvents led to different physicochemical properties, dissolution behavior and long-term stability. The dissolution behavior and long-term stability also varied significantly among excipients. The viscosity of the polymer and the packaging material proved to be important to the long-term stability.

CONCLUSION

For spray-dried products containing fenofibrate, the excipients were ranked according to dissolution and stability performance as follows: PVP derivatives >> HPMC 2910/15, HPMCAS-MF, HP-β-CD >> PVP:PVA 2:8. EtOH 96% proved superior to acetone/water for spray drying with polymers. The results were used to propose a general approach to developing spray-dried formulations of poorly soluble drugs.