comparison of explanation methods of encapsulation efficacy of hydroquinone in a liposomal system

One of the most important parameters describing the liposomal formulation of hydroquinone is encapsulation efficacy. For the efficacy evaluation of hydroquinone trapped in liposomal structure, there is a need to first separate liposome from the matrix surrounding it

There are various separation techniques; however, in this study, the three techniques of centrifuges with and without washing and dialysis were used

From among the laboratory techniques, an appropriate method is the one that offers responses with a high repeatability

The statistical calculations revealed that encapsulation efficacy with a direct method resulted from a separation via the techniques of dialysis and centrifuge without washing had the highest dispersion with SDs of 6.1 and 8.7, respectively, while the SD value in the technique of centrifuge with washing was 5.2. Through an indirect method, hydroquinone encapsulation efficacy showed the best repeatability with SD values of 2.8 and 2.1 by using the two techniques of centrifuge and centrifuge filtration, respectively

It seems that the treatments leading to the dilution of hydroquinone formulation would result in hydroquinone leakage and a reduction of encapsulation efficacy

It seems that measurement of hydroquinone encapsulation efficacy with an indirect method is a better choice; therefore, a centrifuge technique was utilized to report the mentioned efficacy at a speed of 45000 rcf and duration of 30 min due to having a reasonable price and ease of access?

UV spectrophotometric determination and validation of hydroquinone in liposome

The method has been developed and validated for the determination of hydroquinone in liposomal formulation. The samples were dissolved in methanol and evaluated in 293 nm. The validation parameters such as linearity, accuracy, precision, specificity, limit of detection [LOD] and limit of quantitation [LOQ] were determined. The calibration curve was linear in 1-50 microg/mL range of hydroquinone analyte with a regression coefficient of 0.9998. This study showed that the liposomal hydroquinone composed of phospholipid [7.8%], cholesterol [1.5%], alpha ketopherol [0.17%] and hydroquinone [0.5%] did not absorb wavelength of 293 nm if it diluted 500 times by methanol. The concentration of hydroquinone reached 10 microg/mL after 500 times of dilution. Furthermore, various validation parameters as per ICH Q2B guideline were tested and found accordingly. The recovery percentages of liposomal hydroquinone were found 102 +/- 0.8, 99 +/- 0.2 and 98 +/- 0.4 for 80%, 100% and 120% respectively. The relative standard deviation values of inter and intra-day precisions were <%2. LOD and LOQ were 0.24 and 0.72 microg/mL respectively

effect of silver nanoparticles on Staphylococcus epidermidis biofilm biomass and cell viability

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

Review of the pharmacological and toxicological effects of Salvia leriifolia

Salvia leriifolia Benth. [vernacular names such as Nuruozak and Jobleh] is a perennial herbaceous plant that grows exclusively in south and tropical regions of Khorasan and Semnan provinces, I. R. Iran. Unlike other species of Salvia genus, the chemical constituents of S. leriifolia are not well recognized. The stem oil of the plant consisted mainly both monoterpenes and sesquiterpenes, while in leaf and flower oils monoterpenes predominated over sesquiterpenes. In recent years, the different properties of this plant such as the attenuation of morphine dependence, hypoglycemic, antinociceptive and anti-inflammatory, antioxidant, antiischemia, anticonvulsant, antiulcer effects, antibacterial activities and antimutagenic effects were evaluated. These effects introduce this plant for more toxicological and clinical trials evaluations as a herbal medicine

In vitro evaluation of methylxanthines and some antibiotics: interaction against staphylococcus aureus and pseudomonas aeruginosa

The development of resistance to antimicrobial agents is a major problem in chemotherapy. Finding agents which potentiate antimicrobial activity could be favorable. There are some reports that methylxanthines changed the inhibitory effect of antibacterial agents. Thus, possible synergistic effect of methylxanthines aminophylline and caffeine on some antibiotics, carbenicillin, ceftizoxime and gentamicin, which are effective on P. aeruginosa and Staphylococcus aureus, were studied. The interaction of methylxanthines and antibiotics were studied in vitro using a checkerboard method. At concentrations of 0.25-4 mg/ml, aminophylline and caffeine decreased the MIC of the antibiotics 2-4 times against P. aeruginosa and Stqph. aureus. Both methylxanthines also reduced the minimum bactericidal concentration of the antibiotics by up to 2 times. Caffeine and aminophylline had no antimicrobial effect themselves. The results of the present study reveal that aminophylline and caffeine potentiated the antimicrobial action of carbenicillin, ceftizoxime and gentamicin against Staph. aureus and P. aeruginosa

In vitro antibacterial activity of rheum ribs extract obtained from various plant parts against clinical isolates of gram-negative pathogens

Rheum ribes is among the Polygonaceae family which is endemic in Iran and a few neighboring countries. In this investigation, antibacterial effects of root, stalk and leaves extracts of Rheum ribes on a few common clinical isolates of gram negative pathogens were studied, using the cup plate and paper disc methods. Gram negative microorganisms studied were Escherichia coli, Klebsiella pneumoniae, Proteus spp., Pseudomonas aeruginosa and Neisseria gonorrhoeae. For examination of pathogenic microorganisms in the cup plate and disc diffusion method, methanolic extracts of different plant parts at concentrations of 250 and 500 micrograms per cup or disc, were used. The root and leaves extracts have demonstrated significant antibacterial activities in both methods. However, stalk extracts showed a lower degree of antibacterial activity than the root and leaves extracts. Generally, the extracts showed a broad spectrum of activity, although they were more effective against P. aeruginosa and Proteus spp. in comparison with the positive control. The results suggested that extracts of Rheum ribes could be effectively used against clinical isolates