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The aim of this study was to characterize the formation of emulsions by droplet size analysis and turbidimetry during reconstitution from a solid dosage form, namely from dry emulsion systems, which carry an oil phase for poorly soluble active ingredients. For the dry emulsion systems tablets were prepared either from oil-in-water systems using a freeze-drying process or through direct compression containing the same oil and excipients. The ratios of oil to emulgents and oil to xanthan gum were equal in both methods. In the preparation methods applied, mannitol, erythritol and lactose were used as excipients and mannitol was found to be the most effective excipient based on droplet size reconstitution, turbidimetry and physical properties. Quality control involved testing the physical properties of tablets and characterizing the reconstituted emulsions., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Different calculations of the hydrophilie-lipophilie balance (HLB) value of Sorbitan fatty acid ester are discussed in literature. Influence on the required HLB value of ethyl oleate was investigated using several emulsifier blends: Span 80/Tween 20, Oleth-3/Steareth-20, Oleth-5/Steareth-20, Oleth-3/PEG-40-Stearate. The calculations of the HLB value of Span 80 have a bearing influence on the determination of the required HLB value. The postulated transferability of the determined required HLB value by the Tween 20/Span 80 system compared to other emulsifier systems is depending on the used equation. Additionally, the required HLB values of the pharmaceutical oils coco-caprate/caprylate and cetearyl isononanoate were determined empirically by preparing submicron emulsions. [ABSTRACT FROM PUBLISHER]

Abstract: The characterization of rosemary essential oil (EO) for its formulation in biodegradable emulsions has been carried out. Firstly, the required HLB (hydrophile–lipophile balance) value of the oil was determined to be 15 based on droplet size analysis and the stability of emulsions with synthetic surfactants. Moreover the emulsion resulted to be stable after 50 days of storage in ambient conditions. Secondly, four biodegradable and non-toxic surfactants derived from starch were tested. The effect of these surfactants was analyzed by measuring interfacial tension between the oil and the aqueous phase. [Copyright &y& Elsevier]

Abstract: Stable emulsions are best formulated with emulsifiers or combinations of emulsifiers, which possess HLB values close to the required HLB of the oil phase. In this work, we have investigated the application of this established method to the development of multiple emulsions. This is of particular interest, since multiple emulsions are highly sensitive in terms of variations of the individual components as a result of the presence of two thermodynamically unstable interfaces. However, multiple W/O/W emulsions are potential skin delivery systems for water-soluble active pharmaceutical ingredients as a result of their pronounced encapsulation properties. Firstly, a suitable primary emulsion was developed based on required HLB determinations of the investigated oils. Secondly and based on the required HLB, multiple W/O/W emulsions were developed using the most appropriate primary emulsion and 1% of hydrophilic emulsifier blends in order to stabilise the second interface. In order to find the appropriate mixtures of hydrophilic emulsifiers, the required HLB for the primary W/O emulsion was determined using two different chemical classes of emulsifier blends, i.e. polyethoxylated ethers and polyethoxylated esters. The physicochemical parameters of the formulations were characterised by means of rheological measurements, droplet size and creaming volume observations as well as by means of conductivity analysis. As discovered, all methods are appropriate for determining the required HLB determination with the exception of the rheological data. Referring to the primary emulsions tested, required HLB values of 4.3–4.7 using paraffin as the oil phase resulted in stable emulsions. Irrespective of the emulsifiers used, the finest droplets, lowest conductivity and minimal creaming volume were obtained for the multiple emulsions at required HLB values between 15 and 15.5 using paraffin as the oil phase. What is more, using a polyethoxylated ether instead of a polyethoxylated fatty acid ester resulted in more stable multiple emulsions. [Copyright &y& Elsevier]

The goals of this articles are to find a correlation between the required HLB values and the solubility parameters of oils; find a more precise correlation between the required HLB values and the dielectric constant, than the one obtained by other authors; and to determine the required HLB values for o/w emulsions of solid fatty acids and alcohols from the values of the solubility parameters and dielectric constants, that could be more trustful than the ones obtained by the methodology proposed by Griffin. It was obtained lineal relation between required HLB and solubility parameter (r = 0.995). Also it was observed lineal relations between required HLB and dielectric constants or logarithm of the dielectric constant more precise than the one obtained by other authors. [ABSTRACT FROM AUTHOR]

This study focused on assessing the physical stabilization of several oil-in-water nanoemulsions obtained by Ultra-High-Pressure Homogenization (UHPH). For this, several formulations were developed using Sacha inchi oil (~9.3% w/w), ultra-pure water, preservatives (0.44% w/w) and several emulsifier mixtures at 2% w/w, which were combined in different proportions to provide surfactant blends with HLB values (HLBB) of 6, 8, 10, and 12. The conventional emulsions were then subjected to UHPH (40,000 psi) and underwent thermal stability assays for 4 weeks, where changes in creaming index, droplet size, polydispersity, viscosity and zeta potential, were evaluated. The results showed the required HLB (HLBr) for SI oil was approximately 8 and when UHPH was utilized, high physical stability of emulsified systems was achieved. It was also found that the increase in HLBB for the emulsions submitted to UHPH leads to a less viscosity, smaller droplet sizes and more homogeneous system. • The required HLB of sacha inchi oil is approximately 8. • The UHPH increases considerably the physical stability of oil-in-water emulsion. • The required HLB value for sacha inchi oil is not necessary when using UHPH. • The increase in HLBB in nanoemulsions leads to less viscosity, smaller and more homogeneous systems. [ABSTRACT FROM AUTHOR]