bahman khameneh

Today, the non-covalent PEGylation methods of protein pharmaceuticals attract more attention and possess several advantages over the covalent approach. In the present study, Amino Acid-mPEGs (aa-mPEGs) were synthesized, and the human Growth Hormone (hGH) stability profile was assessed in their presence and absence.

aa-mPEGs were synthesized with different amino acids (Trp, Glu, Arg, Cys, and Leu) and molecular weights of polymers (2 and 5 KDa). The aa-mPEGs were analyzed with different methods. The physical and structural stabilities of hGH were analyzed by SEC and CD spectroscopy methods. Physical stability was assayed at different temperatures within certain intervals. Molecular dynamics (MD) simulation was used to realize the possible mode of interaction between protein and aa-mPEGs. The cell-based method was used to evaluate the cytotoxicity.

HNMR and FTIR spectroscopy indicated that aa-mPEGs were successfully synthesized. hGH as a control group is known to be stable at 4 °C; a pronounced change in monomer degradation is observed when stored at 25 °C and 37 °C. hGH:Glu-mPEG 2 kDa with a molar ratio of 1:1 to the protein solution can significantly increase the physical stability. The CD spectroscopy method showed that the secondary structure of the protein was preserved during storage. aa-mPEGs did not show any cytotoxicity activities. The results of MD simulations were in line with experimental results.

This paper showed that aa-mPEGs are potent excipients in decreasing the aggregation of hGH. Glu-mPEG exhibited the best-stabilizing properties in a harsh environment among other aa-mPEGs.

Microbial biofilms are one of the main causes of persistent human infections. Encapsulation of an antibiotic and a biofilm dispersal agent within a nano-carrier has been recognized as a novel approach to combat the problem of biofilm-related infections. Here, we develop the nanoliposomal formulation for delivery of vancomycin in combination with cis-2- decenoic acid (C2DA), to Staphylococcus epidermidis biofilm. The effects of the formulations were studied at two stages: biofilm growth inhabitation and biofilm eradication.

Liposomal formulations were prepared by the solvent evaporation dehydrationrehydration method and were evaluated for size, zeta potential, and encapsulation efficacy. The ability of different agents in free and encapsulated forms were assessed to evaluate the anti-biofilm activities.

Vancomycin and C2DA were successfully co-encapsulated in the same nanoliposome (liposomal combination). The zeta potential values of the liposomal formulations of vancomycin, C2DA, and the liposomal combination were 37.2, 40.2, 51.5 mV, and the mean sizes of these liposomal formulations were 167.8±1.5, 215.5±8.8, 235.5±0.01, respectively. Encapsulation efficacy of C2DA was 65% and about 40% for vancomycin. The results indicated that liposomal combination exerted strong anti-biofilm activities, slightly exceeding those observed by the free form of a combination of vancomycin and C2DA, but higher than either agent used alone in their free forms. The anti-biofilm activity of formulations followed concentration and time-dependent manner.

The combination of vancomycin and C2DA could inhibit biofilm formation. Employing the liposomal combination is a considerable method to remove bacterial biofilm.

Staphylococcus epidermidis is a common cause of medical device-associated infections due to biofilm formation, and its elimination is extremely challenging. Although rifampin efficacy against S. epidermidis biofilms has been confirmed, its use as a single agent may lead to resistance. As such, it is assumed that the combination of rifampin and N-acetylcysteine (NAC) could exert additive effects as a mucolytic agent. The present study aimed to use a liposomal system for the delivery of these compounds to bacterial biofilm.

Liposomal formulations were prepared using the dehydration-rehydration method and characterized in terms of the size, zeta potential, and encapsulation efficacy. In addition, the ability of various formulations in the eradication of bacterial biofilm and inhibition of biofilm formation was assessed based on the optical density ratio.

The zeta potential of the liposomes was positive, and the mean size of these liposomal formulations was less than 200 nanometers. Liposomal rifampin was the most effective formulation against S. epidermidis, and the anti-biofilm activity of most of the formulations was concentration-dependent and time-dependent.

According to the results, the rifampin-loaded liposomes were effective against S. epidermidis biofilm formation.

The in vivo efficacy of nanoliposomal formulation of vancomycin against methicillin-resistant Staphylococcus aureus (MRSA) assessed.

Nanoliposomal formulations were prepared and characterized. The in vivo study was carried out on rabbits which received liquid culture medium containing MRSA under anesthesia. After 48 hr, the eyes treated with the liposomal and free form of vancomycin. The rabbits were euthanized at predesignate intervals at 12, 24, 48, 96, 144 hr intervals injection. The antibacterial activity of different vancomycin formulations was assayed by the time killing method.

The zeta potential, mean sizes and encapsulation efficacy of liposomal vancomycin were 29.7 mV, 381.93±30.13 nm and 47%, respectively. The results of time–killing studies indicated that the liposomal formula was more effective than the free form of vancomycin.

The results of this study revealed that liposomal vancomycin formulation is a powerful nano-antibacterial agent to combat infectious endophthalmitis.

The quality of extracts used in the skin prick test directly influences the interpretation of the test. Accordingly, the outcomes and effectiveness of immunotherapy for the management of IgE-mediated allergies depend on the quality of the extracts used. Excipients, which are pharmacologically inert ingredients, are intentionally added to the active ingredients. The aim of this study was to address optimum excipients for stability Platanus (P.) orientalis extract. In this study the excipients examined were l-lysine (20 mM), l-cysteine (20 mM), albumin (0.5%), sorbitol (2%), sucrose (750 mM), trehalose (20 mM), D-mannitol (2% w/v), urea (100 mM) and Tween-20 (0.1%). Their effects on P. orientalis extract stability were analyzed using an inhibition enzyme linked immune assay at 37 ᵒC. A mixture of lysine (20 mM), trehalose (20 mM), and D-mannitol (2% w/v) conferred the greatest stability on the P. orientalis extract. The P. orientalis extract stability was increased by a mixture of lysine (20 mM), trehalose (20 mM), and D-mannitol

In recent years, there has been an increasing interest in using herbal products to overcome bacterial resistance. The aim of this study was to investigate the effect of lemon verbena aqueous extract, verbascoside and caffeine in combination with gentamicin against standard and clinical isolates of Staphylococcus aureus and Escherichia coli strains.
The MIC and MBC values of different antibacterial agents against bacterial strains were determined. The effect of co-administration lemon verbena extract, verbascoside, and caffeine and gentamicin was studied in vitro using a checkerboard method and calculating fraction inhibitory concentration index (FICI).
Herbal extract, verbascoside and caffeine alone showed no inhibitory effects on any of the bacterial strains (at doses up to 200 mg/ml). Herbal extract, verbascoside and caffeine were able to decrease the MIC of gentamicin against the standard resistant strains and two clinical isolates. Among these combinations, the co-administration of verbascoside and gentamicin was more effective and synergistic activities (FICI The results of the present study revealed that herbal extract, verbascoside and caffeine potentiated the antimicrobial action of gentamicin against some clinical isolates of S. aureus and E. coli.

At the present study, relationship between phagocytosis of PLGA particles and combined effects of particle size and surface PEGylation was investigated. Microspheres and nanospheres (3500 nm and 700 nm) were prepared from three types of PLGA polymers (non-PEGylated and PEGylation percents of 9% and 15%). These particles were prepared by solvent evaporation method. All particles were labeled with FITC-Albumin. Interaction of particles with J744.A.1 mouse macrophage cells, was evaluated in the absence or presence of 7% of the serum by flowcytometry method. The study revealed more phagocytosis of nanospheres. In the presence of the serum, PEGylated particles were phagocytosed less than non-PEGylated particles. For nanospheres, this difference was significant (P<0/05) and their uptake was affected by PEGylation degree. In the case of microsphere formulation, PEGylation did not affect the cell uptake. In the serum-free medium, the bigger particles had more cell uptake rate than smaller ones but the cell uptake rate was not influenced by PEGylation. The results indicated that in nanosized particles both size and PEgylation degree could affect the phagocytosis, but in micron sized particles just size, and not the PEGylation degree, could affect this.

In the current study, sunscreen and moisturizing properties of solid lipid nanoparticle (SLN)-safranal formulations were evaluated. Series of SLN were prepared using glyceryl monostearate, Tween 80 and different amounts of safranal by high shear homogenization, and ultrasound and high-pressure homogenization (HPH) methods. SLN formulations were characterized for size, zeta potential, morphology, thermal properties, and encapsulation efficacy. The Sun Protection Factor (SPF) of the products was determined in vitro using transpore tape. The moisturizing activity of the products was also evaluated by corneometer. The SPF of SLN-safranal formulations was increased when the amount of safranal increased. Mean particle size for all formulas was approximately 106 nm by probe sonication and 233 nm using HPH method. The encapsulation efficiency of safranal was around 70% for all SLN-safranal formulations. The results conclude that SLN-safranal formulations were found to be effective for topical delivery of safranal and succeeded in providing appropriate sunscreen properties.

The purpose of this study was preparation and evaluation of PLGA nanospheres containing the influenza virus and different adjuvants, Quillaja saponin (QS) and CpG-ODN. Nanospheres were prepared using the double emulsion-solvent evaporation method. The morphological and physicochemical properties were studied by scanning electron microscopy (SEM), determination of zeta potential, encapsulation efficiency and release profile. The particle size of formulations was less than 1000 nm, except for formulations containing antigen. The results were confirmed with SEM images. Encapsulation efficiency of antigen, QS and CpG ODN were 80%, 62% and 31%, respectively. The zeta potential of nanospheres was about -30 mV. The burst release was observed for all encapsulates and reached to about 48%, 44% and 35% within 90 min for antigen, CpG-ODN and Qs content, respectively. The formulations showed proper physicochemical properties. These nanospheres have good potential to be used as delivery systems/adjuvants for immunization against influenza.

Bacterial biofilm has been considered responsible for many deaths and high health costs worldwide. Their better protection against antibacterial agents compared to free living cells leads to poor treatment efficiency. Nanotechnology is promising approach to combat biofilm infections. The aim of the present study was to eradicate Staphylococcus epidermidis biofilm with silver nanoparticles (SNPs). SNPs were used at different concentrations (two fold dilutions) and incubation times (24, 48, 72 h). The crystal violet staining and pour plate assays were used to assess biofilm biomass and bacterial viability, respectively. The ability of SNPs on biofilm matrix eradication was assessed through optical density ratio (ODr). Positive control was defined as an ODr =1.0. The crystal violet assay indicated that the biofilm matrixes were intact at different concentrations of SNOs and incubation times. There were no significant differences between these parameters (P >0.05). Bacterial enumeration studies revealed that higher concentrations of SNPs were more effective in killing bacteria than lower ones. Although, longer incubation times led to enhancement of anti-biofilm activity of SNPs. The anti-biofilm activity of SNPs was concentration- and time-dependent. The results of this study highlighted that SNPs were effective against cell viability; however they were ineffective against biomass.

Biofilm formation of Staphylococcus epidermidis is a major etiological factor of inducing device-related infections. The ability of biofilm formation by the S. epidermidis was assessed in vitro on two brands of foldable (hydrophilic) and two brands of rigid (hydrophobic) intraocular lens materials in order to investigate the role of lens material in postoperative endophthalmitis. To ensure reproducibility of biofilm formation on intraocular lenses, two strains of S. epidermidis and three quantification methods were performed. The S. epidermidis strains, DSMZ3270 (biofilm-producer) and ATCC12228 (non-biofilm-producer) were applied. Organisms were cultivated on disks of different brands of foldable hydrophilic Intra Ocular Lens (IOL) made of acrylic (Didar, Iran; (A) and Omni, India; (B)), and rigid hydrophobic IOL made of polymethyl methacrylate (PMMA; Didar, Iran; (C) and Hexavision, France; (D)). Biofilms were stained with crystal violet (CV) dye, which is an index of biofilm formation. The bacterial population was counted after biofilm homogenization. Scanning electron microscopy (SEM) was performed to examine the extent of biofilm formation. Adherence of DSMZ3270 strain on both types of foldable and rigid IOLs, was significantly more than ATCC12228 (P < 0.001-0.05 and, P < 0.01-0.05, respectively). The bacterial populations between the lenses were significantly different (P < 0.05). Subsequent studies demonstrated significant differences between brands of foldable and PMMA IOLs. According to statistical analyses the incubation time influenced the biofilm formation on both types of IOLs which meant that by increasing incubation time, the biofilm formation increased. According to the SEM pictures, biofilm seems to be lysed at 72 hours. These data demonstrated that the attachment of bacteria to hydrophilic acrylic IOLs was more than hydrophobic PMMA ones independent of the brand. According to these results the bacterial strain might have more hydrophilic properties. Augmenting the biomass of biofilm by passing of time demonstrated the key role of time in biofilm formation on the IOL surfaces. The differences between IOL brands in the biofilm formation indicated the influence of design parameters for IOLs.

Drug delivery via mucosal routes has been confirmed to be effective in inducing strong immune responses. Liposomes could enhance immune responses and mucoadhesive potentials, make them useful mucosal drug delivery systems. Coating of liposomes by mucoadhesive polymers succeeded in enhancing immune responses. Our studies aim at preparation and characterization of trimethylchitosan-coated nanoliposomes for nasal delivery of a model antigen, tetanus toxoid (TT). Anionic liposomes were prepared by dehydration-rehydration method with an average size of 100 nm and were coated with 0.01% (w/v) solution of trimethyulchitosan (TMC) with 50±10% of quaternization. Surface properties and zeta potential were evaluated by DLS. Antigen stability and integrity were studied by SDS-PAGE electrophoresis. Nasal clearance rate and mucoadhesive properties of liposomes were studied by gamma scintigraphy method using 99mTc-labelled liposomes. The zeta potential of non-coated and TMC-coated liposomes was -40 and +38.8, respectively. Encapsulation rate of tetanus toxoid was 77 ± 5.5%. SDS-PAGE revealed that the antigens remained intact during formulation procedure. Gamma scintigraphy confirmed that both types of liposomes could remain in nasal cavity up to ten folds over the normal residence time for conventional nasal formulations. TMC-coated nanoliposomes have several positive potentials including good mucoadhesive properties, preserved integrity of loaded antigen and presence of TMC as a mucoadhesive polymer with innate immunoadjuvant potential which make them suitable for efficient adjuvant/delivery system.