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A wide variety of surfactants are available in the market with different Hydrophilic-lipophilic balance (HLB) values; therefore, one must choose suitable surfactants and their concentration to give maximum effect in the final product in an early stage of formulation development. The required HLB value of the oil phase was determined by experiments and the emulsifier selected of the same HLB value reduced the number of formulations with increased stability and minimum quantity of emulsifier. This study reviews the importance of the required HLB system and methods of determining it. Further, it also provides the surfactants application in the production of coconut oil emulsion with butter-like properties. The Griffin approach does the conventional way of determining the required HLB value of the oil phase. Various emulsions were prepared with emulsifier blends of Span and Tween, covering all the HLB range as per the final product and emulsion type, and observed regarding their separating/emulsifying properties with variable time or concentration. Interfacial Tension (IFT), Droplet Size, Zeta potential, centrifugal separation measurements of the emulsion prepared with food-grade emulsifiers like Polyglycerol polyricinoleate (PGPR), Distilled Monoglycerides (DMG), and Lecithin, was carried out to identify the best suitable emulsifier and its concentration which gives better emulsion stability. The coconut and sunflower oil blend (70:30, w/w) shows, the required HLB value is 3.7 when it emulsified with 60% of water and found that PGPR + DMG blend gives maximum emulsion stability at 3% of emulsifier concentration. [ABSTRACT FROM AUTHOR]

Khaled Hosny,1– 3 Hani Asfour,4 Waleed Rizg,1– 3 Nabil A Alhakamy,1– 3 Amal Sindi,5 Hala Alkhalidi,6 Walaa Abualsunun,1 Rana Bakhaidar,1 Alshaimaa M Almehmady,1 Sara Akeel,5 Sarah Ali,5 Adel Alghaith,7 Sultan Alshehri,7 Rasha Khallaf8 1Department of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; 2Center of Excellence for Drug Research and Pharmaceutical Industries, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 3Advanced Drug Delivery Research Group, Faculty of Pharmacy, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 4Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah, 21589, Saudi Arabia; 5Oral diagnostic sciences department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia; 6Department of Clinical pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; 7Department of Pharmaceutics, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia; 8Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, 62511, EgyptCorrespondence: Khaled HosnyDepartment of Pharmaceutics, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi ArabiaTel +966 561682377Email elswaify2000@yahoo.com; kmhomar@kau.edu.saIntroduction: Natural oil-based nanoemulsions (NEs) have been widely investigated in many diseases that affect the oral cavity. NEs are delivery systems that enhance the solubility of lipid therapeutics and improve their delivery to target sites; they are known as self-nanoemulsifying drug delivery systems (SNEDDSs). The current investigation’s aim was to produce an oregano essential oil-based nanoemulsion (OEO-SNEDD) that would have antibacterial and antifungal effects against oral microbiota and improve oral health.Methods: Several OEO-SNEDDSs were developed using different percentages of OEO (10%, 14%, and 18%), percentages of a surfactant mixture Pluracare L64:Lauroglycol FCC (18%, 32%, and 36%), Smix ratios (1:2, 1:1, and 2:1), and hydrophilic-lipophilic balances (HLBs) of the surfactant mixture (8, 10, and 12) using the Box‒Behnken design. The optimized concentration of excipients was determined using a pseudoternary phase diagram to obtain the NEs. The formulations were evaluated for their droplet size, stability index, and antibacterial and antifungal activities.Results: The NEs had a droplet size of 150 to 500 nm and stability index of 47% to 95%, and the produced formulation reached antibacterial and antifungal inhibition zones of up to 19 and 17 mm, respectively. The Box‒Behnken design was adopted to get the optimum formulation, which was 18% OEO, 36% Smix, 10.29 HLB of Smix, and a 1.25:1 Smix ratio. The optimized formulation had a lower ulcer index compared with various other formulations evaluated in rats.Conclusion: This study illustrated that OEO-SNEDDSs can provide good protection against oral microbial infections.Keywords: oregano essential oil, nanoemulsion, Box‒Behnken design, ulcer index, required HLB, carvacrol, thymol, stability index

Grape seed oil has wound healing activity since contains compounds such as flavonoids, polyphenols, saponins and linoleic acid. The purpose of this study is formulate emulgel containing grape seed oil with good physical characteristic and observed the wound healing activities of the oil and formulated emulgel. The research was begin with grape seed oil characterization and required HLB determination. The emulgel was made using combination Tween 80 and Span 80 as emulgator and carbomer as gelling agent with variation of oil concentration (10%, 20% and 30%). The formulation then subjected to physical evaluations including organoleptic, pH, spreadability, viscosity and rheology, sterility, and stability tests. Wound healing activity test of selected formula was done on seven groups of male Wistar rats. The emulgel containing grape seed oil with HLB value 8, has good physical, sterility, and stability characteristics. In vivo activity test showed that emulgel containing 20% and 30% grape seed oil have wound healing activity that statistically different compared with control (P0.05).

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. [ABSTRACT FROM AUTHOR]

Context: Garlic oil and Eruca oil have been reported to have excellent antimicrobial activity. However, the exact knowledge of their required hydrophilic–lipophilic balance (rHLB) values to facilitate their emulsification are still not reported in the literature. Objective: The objective of this study is to determine rHLB values of Garlic and Eruca oils to formulate an elegant stable cream formulation enriched with both oils. Materials and methods: Emulsions of both oils were prepared by the bottle method using water, Tween 80 and Span 80. Formulated emulsions were evaluated for creaming index (CI), droplet size, and turbidity to determine rHLB. Utilizing determined rHLB, creams were formulated using a combination of two surfactants, Span 60:Brij 58 (1:2.333) at three different concentrations (2, 4, and 6%). Results: rHLB of Garlic oil and Eruca oil was determined to be 7.92 ± 0.27 and 9.76 ± 0.32, respectively. Stable cream (F1) developed with 2% surfactant blend showed elegant rheological properties, the best antimicrobial activity againstStaphyococcus aureusATCC29737, Escherichia coliATCC25299 S. aureus (MRSA), Malassezia fufur AUMC No. 5173with no skin irritation. In addition, its texture parameters and pH were found to be consistent over 12 months at 25 ± 1 °C and 60% relative humidity. Discussion: The lowest CI, smallest droplet size, and highest turbidity were obtained at the optimum surfactant concentration in the prepared emulsions. Increasing surfactant blend concentration in cream formulations leads to increasing viscosity and consequently decreasing antimicrobial activity. Conclusion: Determination of the rHLB of Garlic and Eruca oils allows the ease of preparation of stable, consistent, and non-irritant cream. [ABSTRACT FROM PUBLISHER]

For the development of ultra-small NLC (usNLC) the determination of the required HLB (hydrophilic lipophilic balance) was found to be a suitable method, i.e., usNLC with a size below 50 nm were obtained by this method. Loading with 5% (w/w) coenzyme Q10 (Q10) led to usNLC with a size of about 85 nm. In comparison to classical NLC with a size of 230 nm and a nanoemulsion with similar size, the Q10 loaded usNLC show a higher release, a higher antioxidant capacity, and a better skin penetration for Q10. The reason for this is a flip–flop core–shell structure of the lipid matrix, i.e., the oil with dissolved active is surrounding the solid lipid based core. As the flip–flop structure was probably achieved by admixing high contents of liquid lipid, oil enriched usNLC might represent a novel and promising carrier system for the improved delivery of lipophilic actives. [ABSTRACT FROM AUTHOR]

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]

Abstract: The methods and results obtained by Griffin et al. in the determination of the hydrophilic–lipophilic balance (HLB) values of non-ionic surfactants and of required HLB values of oil mixtures are reviewed in the present work. HLB values published by Griffin were compared with those obtained by calculations from theoretic chemical formulas. Griffin HLB values of polyoxyethylene alkyl ethers, polyoxyethylene monoesters and propylene glycol monoesters coincide with those obtained from such theoretical chemical formulations. These results demonstrate that, for these surfactants, Griffin did not experimentally obtain their HLB values, but instead calculated them from theoretic formulae. For the calculation of the HLB values of glycerol monostearate, sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters, Griffin''s assumptions were possibly based upon the mean saponification values of the ester and the acid of the fatty acid. It is concluded that the HLB values of non-ionic surfactants were not rigorously defined. Moreover, Griffin could not demonstrate the validity of the assumption that individual required HLB values can be added up to obtain the overall required HLB value of an oil mixture. The HLB and required HLB values published by Griffin should only be taken as approximate guidelines. [Copyright &y& Elsevier]

The turbidity ratio method of evaluating the stabilities of water-in-oil emulsions has been established with two wavelengths (450 and 850 nm) by taking the intensity ratio of two beams. The slopes of turbidity ratio of several water-in-oil emulsions with time were calculated to evaluate the emulsion stabilities at different HLB (Hydrophilie-Lipophile Balance), the amounts of emulsifiers, and water contents. The results of the turbidity ratio technique were consistent with the amount of phase separation of emulsions incubated for 30 days at room temperature. From the turbidity ratio measurements, we determined that the required HLB of diesel oil was about 6.0, and that the stability of emulsion increased with the amount of emulsifier. The increasing amount of the water showed a negative effect on emulsion stability. Finally, this method provides a useful tool for the quick evaluation of the required HLB and the condition of emulsification throughout this study. [ABSTRACT FROM AUTHOR]

The required HLB values of eucalyptus, lippia and peppermint essential oils were determined using droplet size analysis and turbidimetric method on emulsions prepared with emulsifier blends of varying HLB values. The percentage increase in mean droplet diameter and the degree of dispersion of droplet sizes were determined before and after centrifugation of the emulsions. The HLB value of the emulsion with the least dispersion ratio or the least percentage increase in mean droplet diameter was taken as the required HLB of the respective essential oil. The turbidimetric method was validated by the existence of correlation (r=−0.958) between the mean droplet diameter and the turbidity of the emulsions. The turbidity curve went through a maximum at the HLB value where the mean droplet diameter was least. Based on these methods, the required HLB values of eucalyptus, lippia and peppermint oils were determined as 9.8, 12.1 and 12.3, respectively (P<0.05). Liquid paraffin was used as a reference standard and its required HLB fell within literature value. [Copyright &y& Elsevier]

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]