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Microemulsions (ME) are isotropic, thermodynamically stable structures holding a very high concentration of surfactant. Clove oil is essential oil extracted from Syzygium aromaticum which contains eugenol (80-88 %) with low eugenyl acetate and high content of caryophyllene. Nonionic surfactants (Tween in this case) as neutral particles likewise recognized as harmless and biocompatible produces; resist pH alterations in the medium. Cosurfactants are weak amphiphilic fragments which when used alone do not produce MEs, but they powerfully support gathering of the main surfactant. The aim of the current research to formulate clove oil based ME using Tween 20, Tween 80 and glycerin anhydrous as surfactant mixture in a ratio of (1:1). Clove oil and Smix were weighted into glass vials with the weight ratios of 1:9, 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, 8:2, and 9:1 .The prepared formulations were evaluated for their physicochemical properties (pH, particle size and particle size distribution, polydispersity index (PDI), emulsion typre was identified by dye solubility and conductivity test. Stability of ME was examined against freezing-thawing, centrifugation and heating cooling cycle. The results exhibit optimum particle size range from 7.88 - 176 nm for Tmix C3 and T20C8 respectively. pH values ranged from 4.1 - 4.8 and insignificant variation (p > 0.05) established in the original globule dimension for selected MEs that subjected to thermal stability and centrifugation protocols. As a conclusion, such ME possess a potentiality to be a suitable drug delivery system for wide range of the candidate drugs. [ABSTRACT FROM AUTHOR]

Background: Niosomes are vascular systems used as safe and useful carriers for delivering both hydrophilic and hydrophobic drugs. These vesicles are considered as drug delivery systems, which are designed using non-ionic surfactants. Niosomes are designed by mixing of biocompatible and biodegradable non-ionic surfactant (usually spans and tweens) and cholesterol with dispersion in aqueous media. It is composed from a bilayer of non-ionic surfactant with two extents, one of them is hydrophilic and the other is hydrophobic. The purpose of the present study is to prepare diphenhydramine HCl (DPH HCl) proniosomal gel that is capable to convert into niosomal forms on hydration and delivering drug in extended time. Materials and Methods: Proniosomal loading DPH HCl formulas were prepared by coacervation method. Sorbitan esters (Span 20, Span 40, Span 60, and Span 80) and their ethoxylated derivatives (Tween 20, Tween 40, Tween 60, and Tween 80) were used in the preparation of proniosomal formulations. The prepared formulations were evaluated for physical manifestation, pH, shape, vesicles size, entrapment efficiency (EE), and in vitro drug release. Fourier-transform infrared (FT-IR) spectroscopy was used to examine the compatibility between medicine and other ingredients. Results: Results showed that the most prepared niosomal formulations were in the nanosize range and exhibited uniformity in the sizes of the vesicles with higher EE (68.6%-97.83%). FTIR studies indicated that there was no interaction between DPH HCl and other formulation materials of niosomal formulations. The prepared formulations containing Tween surfactants revealed higher release rates when compared with Span formulations. According to the results, niosomal formulation could be formulated for DPH HCl as transdermal delivery system. Conclusion: The above results indicated that DPH was well prepared as proniosomal gel with high EE using coacervation technique. Proniosomal formulation as a drug delivery system seems to be possible with DPH HCl and could act as alternative for delivering the drug with prolonged release at the site of action, in addition to avoid the side effects of drug by the other routes of drug administration. [ABSTRACT FROM AUTHOR]

Background: Metronidazole is nitroimidazole antibiotic that is used for the treatment of numerous infectious diseases caused by different organisms, such as protozoans, Helicobacter pylori, primarily Gram-negative and Gram-positive anaerobic bacteria, and protozoa. The objective of this study was to assess the possibility of using propolis and beeswax in preparation of a matrix form of metronidazole by different techniques. Materials and Methods: Matrices were prepared by melt technique using beeswax and propolis as a release retardant agents. The compatibility between metronidazole and matrices forming agents (propolis and beeswax) was confirmed by differential scanning calorimetry (DSC) and Fourier-transform infrared (FTIR) analysis. Results: The FTIR and DSC analysis showed the stability and compatibility of the drug with other components. Bead matrices were prepared by emulsion congealing techniques by changing the amount of beeswax as a release retardant agent at five ratios mostly1:1, 1:3, 1:5, 1:8, and 1:10 drug to wax ratio. Tween 80 (2% w/v) was used as a surfactant. It was found that by increasing beeswax content, the particle size of spherical particles was increased. The drug release shows initial fast release followed by constant release. Conclusion: According to dissolution studies, it can be concluded that the use of beeswax and propolis as matrices forming agents of metronidazole is a very promising manner to sustain the release of drug. [ABSTRACT FROM AUTHOR]