卵磷脂微乳的制备与理化性质考察

目的：对25℃各卵磷脂系统中微乳的形成区域以及微乳理化性质随系统中各组分的变化情况进行研究。方法：卵磷脂作表面活性剂,短链醇类作助表面活性剂,采用不同油相考察相图中油包水型微乳形成区域的变化;选择不同处方组分的微乳测定微乳理化性质。结果：各个系统均可形成油包水型微乳,室温下放置数月未见分层。卵磷脂/醇质量比(K_m)与水相量对微乳的粘度有显著影响;电导率随着水相含量增加而增大;微乳的粒径随着体系中水相的增加而增大。结论：K_m较大,水相含量适中的微乳体系较为适合制备药物载体。     

Particle size analysis of concentrated phospholipid microemulsions: I. Total intensity light scattering

Water-in-oil phospholipid microemulsions prepared from a constant total surfactant/cosurfactant concentration of 25 wt% at four different lecithin/alcohol weight ratios (K _m of 1∶1, 1.5∶1, 1.77∶1, and 1.94∶1) and containing water concentrations (or volume fractions) ranging from 2.0 to 26 wt% (or 0.04 to 0.26) have been examined at 298 K using total intensity light scattering. The data obtained were analysed using the hard-sphere model of Percus-Yevick, modified to account for the partitioning of the alcohol between the various phases. The light-scattering results showed that, regardless of the K _m or the alcohol used, a minimum water concentration of at least 9 wt% was required for the formation of a microemulsion; although this value was reasonably constant for each of the alcohols investigated, there was a tendency for a slightly higher concentration of water to be required for microemulsion formation at higher K _m values. Simple calculations suggested that a microemulsion was formed only when sufficient water was present to satisfy the hydration of both the phospholipid head groups and the hydroxyl groups of the cosurfactant associated with the droplet. At water concentrations lower than this minimum value, a cosolvent system was observed. In all systems above this minimum concentration, as the concentration of water increased, the size of the microemulsion droplets also increased. Surprisingly, however, there was little difference in the size of the microemulsion droplets obtained with the different alcohols, regardless of the K _m, although for a particular alcohol there was some indication that the higher K _m systems produced the slightly smaller droplets for an equivalent water concentration. There was also a suggestion that the more hydrophobic alcohols produced slightly smaller droplets than the more polar alcohols at the same K _m.     

Investigations into the formation and characterization of phospholipid microemulsions. IV. Pseudo-ternary phase diagrams of systems containing water-lecithin-alcohol and oil; The influence of oil

Phase studies have been performed for quaternary systems composed of egg lecithin, cosurfactant, water and oil. The lecithin used was the commercially available egg lecithin Ovothin 200 (which comprises ≥ 92% phosphatidylcholine). The cosurfactants employed were propanol and butanol, and these were used at lecithin/cosurfactant mixing ratios (K_m) of 1:1 and 1.94:1 (weight basis). Six polar oils were investigated, including the alkanoic acids, octanoic and oleic, their corresponding ethyl esters and the medium and long chain triglycerides, Miglyol 812 and soybean oil. All oils, irrespective of the alcohol and the K_m used, gave rise to systems that produced a stable isotropic region along the surfactant/oil axis (designated as a reverse microemulsion system). In addition, the systems incorporating propanol at both K_m and butanol at a K_m of 1.94: 1, generally gave rise to a liquid crystalline region and, in some cases, a second isotropic non-birefingent area (designated as a normal microemulsion system). The phase behaviour observed was largely dependent upon the alcohol and K_m used and the size and the polarity of the oil present.     

Particle size analysis of concentrated phospholipid microemulsions: II. Photon correlation spectroscopy

The solvated droplet size of concentrated water-in-oil (w/o) microemulsions prepared frome egg and soy lecithin/water/isopropyl myristate and containing short-chain alcohol cosurfactants has been determined using photon correlation spectroscopy (PCS). The effect of increasing the water volume fraction (from 0.04 to 0.26) on the solvated size of the w/o droplets at 298 K has been investigated at 4 different surfactant/cosurfactant weight ratios (K _m of 1∶1, 1.5∶1, 1.77∶1, and 1.94∶1); in all cases the total surfactant/cosurfactant concentration was kept constant at 25% w/w. In the case of the microemulsions prepared from egg lecthin, the diffusion coefficients obtained from PCS measurements were corrected for interparticulate interactions using a hard-sphere model that necessitated estimation of the droplet volume fractions, which in the present study were obtained from earlier total intensity light-scattering (TILS) studies performed on the same systems. Once corrected for hard-sphere interactions, the diffusion coefficients were converted to solvated radii using the Stokes-Einstein equation assuming spherical microemulsion droplets. For both egg and soy lecithin systems, no microemulsion droplets were detected at water concentrations less than 9 wt% regardless of the alcohol and K _m used, suggesting that at low concentrations of added water, cosolvent systems were formed. At higher water concentrations, however, microemulsion droplets were observed. The changes in droplet size followed the expected trend in that for a fixed K _m the size of the microemulsion droplets increased with increasing volume fraction of water. At constant water concentration, droplet size decreased slightly upon increasing K _m. Interestingly, only small differences in size were seen upon changing the type of alcohol used. The application of the hard-sphere model to account for interparticulate interactions for the egg lecithin systems indicated that the uncorrected diffusion coefficients underestimated particle size by a factor of slightly less than 2. Reassuringly, the corrected droplet sizes agreed very well with those obtained from our earlier TILS study.     

Design and Evaluation of Microemulsion Gel System of Nadifloxacin

Topical microemulsion systems for the antiacne agent, nadifloxacin were designed and developed to overcome the problems associated with the cutaneous delivery due to poor water solubility. The solubility of nadifloxacin in oils, surfactants and cosurfactants was evaluated to screen the components of the microemulsion. Various surfactants and cosurfactants were screened for their ability to emulsify the selected oily phase. The pseudoternary diagrams were constructed to identify the area of microemulsion existence. The influence of k_m (surfactant/cosurfactant) ratio on the microemulsion existence region was determined and optimum systems were designed. The systems were assessed for drug-loading efficiency and characterised for optical birefringence, pH and refractive index, robustness to dilution, globule size, drug content and thermodynamic stability. Optimised microemulsion systems were formulated into gel form and evaluated for viscosity, spreadability, drug content, ex vivo skin permeation and antibacterial activity. The maximum solubility of nadifloxacin in the microemulsion system was found to be 0.25%. The nadifloxacin microemulsions had a small and uniform globule size (67.3-121.23 nm). The stability results revealed that all formulations showed a stable globule size and the polydispersity index under stress conditions. Incorporation of nadifloxacin in microemulsion gel increased the ex vivo skin permeation and antibacterial activity when compared to marketed cream.     

以油包水型微乳为载体促进氟尿嘧啶的经皮渗透

以磺化琥珀酸二辛酯钠 (AOT) 为主要表面活性剂,制备氟尿嘧啶油包水型微乳制剂,以促进药物的经皮渗透。以伪三元相图为基础,依据微乳区域大小, 初步筛选微乳处方;用改进的Franz扩散池和离体小鼠皮肤研究氟尿嘧啶的透皮速率,以单位面积的透皮累积渗透量 (Q_n) 为指标, 考察微乳处方中助表面活性剂的种类、水相比例、混合表面活性剂比例、表面活性剂和助表面活性剂质量比和载药量对离体鼠皮透皮吸收的影响, 优化处方。结果表明,氟尿嘧啶微乳的优化处方为含药0.5%（w/v）,水30%,混合表面活性剂（AOT/Tween 85, K_m = 2）20%, 油相（IPM）49.5%,经皮渗透符合一级速率方程,12 h累积渗透量为（1 355.5 ± 41.1）μg·cm^-2, 分别为0.5%药物水溶液和2.5%（w/w）市售乳膏（O/W）的19.1和7倍。水/AOT/Tween 85/IPM微乳系统能促进5-氟尿嘧啶的透皮吸收, 可以作为氟尿嘧啶等亲水性但水溶性差和渗透性差的药物的新型经皮给药载体。

     

Physicochemical characterization and evaluation of a microemulsion system for antimicrobial activity of glycerol monolaurate

The purpose of this study was to improve the depression, enhance the bioavailability, hence strengthen the antimicrobial ability of poorly water-soluble glycerol monolaurate (GML) by loading it in microemulsion system. Microemulsions were prepared with GML as oil, tweens as surfactant, and medium-and-short chain alcohols at different ratio as cosurfactants. The effect of the ratio of surfactant to cosurfactant on the stability of microemulsion was tested. And the effect of the composition and ratio of cosurfactant and the effect of potassium sorbate dissolved in water at different concentration on the area of O/W microemulsion region in pseudo-ternary phase diagrams were also investigated. The results showed that the microemulsion is most stable when the ratio of surfactant to cosurfactant was 3:2, the suitable cosurfactant is pentanol to dodecane at 2:1, the area of O/W microemulsion region in pseudo-ternary phase diagram increased with increasing content of potassium sorbate. The conclusion of this study was that GML loaded in microemulsion had much higher anti-microbial activity than GML alone.     

亚甲蓝油包水微乳的制备及其淋巴示踪特性的考察

目的研究亚甲蓝油包水微乳的处方工艺,并对其淋巴示踪特性进行研究。方法助表面活性剂浓度法绘制伪三元相图,考察油相、表面活性剂、助表面活性剂及其浓度对微乳形成的影响,正交设计优化处方,透射电镜观察形态,激光散射法测定粒径。通过小鼠右后脚掌皮下注射,观察小鼠腘淋巴结、髂淋巴结及腹主动脉(右肾)淋巴结的蓝染情况。结果亚甲蓝微乳的最终处方为m(大豆油)∶m[Span80-Tween80(HLB=8)]∶m(Transcutol P)∶m(质量分数为5%的葡萄糖溶液)=54.0∶36.0∶5.4∶3.6,载药质量分数为1%。亚甲蓝微乳外观圆整而呈球状,平均粒径为74.11 nm,30 m in内可将小鼠三级淋巴结蓝染。结论亚甲蓝微乳是一种具有开发前景的淋巴示踪剂,可使示踪更加准确、有效。     

Assessment of the percutaneous penetration of indomethacin from soybean oil microemulsion: effects of the HLB value of mixed surfactants

The objective of this study was to evaluate the influence of the ratios or the hydrophile-lipophile balance (HLB) values of Cremophor EL and Span 80 on the phase behavior of the O/W microemulsions and the percutaneous absorption and penetration of indomethacin microemulsions. The existence of microemulsion regions is investigated in quaternary systems composed of soybean oil/Cremophor EL and Span 80 (mixed surfactants)/diethylene glycol monoethyl ether (cosurfactant)/water by constructing pseudo-ternary phase diagrams at various Cremophor EL/Span 80 ratios. In addition, five microemulsion formulations with various mixed surfactants HLB values were evaluated by in vitro penetration experiments using mouse skin and Franz diffusion cells. The flux and amount of indomethacin penetration from 5 microemulsion formulations were significantly different from the control, and the enhance ratios ranged from 2.38 to 4.68 and 2.11 to 4.23, respectively. The HLB value of mixed surfactants in the formulations was a principal factor in determining the percutaneous penetration of the drug. The flux and amount of drug penetration increased gradually with increasing content of the lipophilic surfactant Span 80 and skin retention was highest for mixed surfactants with a HLB value of 7.6. Therefore, it is suggested that the presence of mixed surfactants was beneficial in the formation of O/W microemulsions and enhanced percutaneous penetration of indomethacin.     

The effect of component of microemulsions on transdermal delivery of buspirone hydrochloride

The aim of this study was to evaluate the influence of components such as type, level, and hydrophilic-lipophilic balance (HLB) value of surfactant, type and amount of cosurfactant, and drug concentration on the permeability of buspirone hydrochloride microemulsions through rat skin. The cumulative amount at 24 h ranged from 502.2 ± 57.8 to 1754.3 ± 616.6 μg/cm(2), flux ranged from 23.03 ± 1.84 to 83.36 ± 25.08 μg/(cm(2)/h), and lag time ranged from 3.0 to 4.7 h, indicating that the permeation parameters of buspirone from microemulsions were markedly influenced by the composition of microemulsions. In comparison with the effect of composition of microemulsions on the buspirone permeation capacity, it was found that microemulsions containing surfactant with HLB value of 11.16 possessed higher flux. The viscosity of microemulsions increased, flux decreased, and lag time was prolonged when amount of surfactant in microemulsions increased. The various cosurfactants can also influence the microemulsion formation and drug permeability. The microemulsion with ethanol as cosurfactant had higher permeation rate. However, the buspirone microemulsion with higher flux can provide the therapeutic minimum effective concentration, at workable administrated area about 3.3-5.8 cm(2), demonstrating microemulsions could be a promising drug carrier for transdermal delivery systems.     

长春西汀微乳的优化及其理化性质的考察

目的选择适宜比例的油相、表面活性剂、助表面活性剂和水相制备长春西汀微乳制剂以增加药物的溶解度和经皮渗透量，优化处方，并对其理化性质和刺激性进行研究。方法绘制伪三元相图，确定各相的比例，以经皮稳态渗透流量为指标，利用单纯形网格法优化处方，并考察优化微乳的pH、粘度、电导率、折光率、粒径分布等理化性质。采用MTT法考察微乳制剂对人体皮肤细胞系模型Hacat细胞的毒性。结果O/W微乳在相图中的区域随着表面活性剂和助表面活性剂比例的增加而增加；单纯形网格优化法预测的指标值与实测值相近，所得的优化微乳性质稳定，对Hacat细胞无刺激性，与阴性组无显著性差异。结论长春西汀微乳制剂中药物的溶解度极大提高，经皮稳态渗透流量显著增大，安全稳定，可作为经皮给药的新型载体。     

Formulation design of microemulsion for dermal delivery of penciclovir

The purpose of the present study was to evaluate the potential application of microemulsions as a dermal drug delivery loading penciclovir. The pseudo-ternary phase diagrams were developed for various microemulsion formulations composed of oleic acid (oil phase), Cremorphor EL (surfactant) and ethanol (cosurfactant). Composition of microemulsion systems was optimized using simplex lattice mixture design including the concentrations of surfactant, cosurfactant and water (independent variables) and the solubility and the cumulative amount of penciclovir permeated through excised mouse skins per unit area (response variables). The physicochemical properties of the optimized microemulsion and the permeating ability of penciclovir from microemulsions were also investigated. The results showed that the optimized microemusion formulation was composed of oleic acid (5%, w/w), Cremorphor EL (20%, w/w), ethanol (30%, w/w) and water (45%, w/w). The mean particle diameter was 36.5nm and solubility of penciclovir in the emulsion was 7.41 mg g(-1). The cumulative amount of penciclovir permeated through excised mouse skins from microemulsion was about 3.5 times that of the commercial cream. The conclusion was that the permeating ability of penciclovir was significantly increased from the microemulsion formulation compared with commercial cream.     

Transdermal delivery of hydrocortisone from eucalyptus oil microemulsion: effects of cosurfactants

This study investigated the effects of cosurfactants on the transdermal delivery of hydrocortisone (model drug) from eucalyptus oil microemulsion. Eucalyptus oil which was successfully employed for steroidal drugs was used as the oil. Tween 80 which was readily miscible with eucalyptus oil was used as surfactant. Ethanol, isopropanol and propylene glycol which are relatively tolerable by the skin were employed as cosurfactants. Pseudo-ternary phase diagrams were constructed in the presence and absence of cosurfactants. Microemulsion formulations containing 20% oil, 20% water and 60% of either Tween 80 or 1:1 surfactant/cosurfactant mixture were compared. Incorporation of cosurfactants expanded the microemulsion zone. The cosurfactant free microemulsion was viscous showing pseudo-plastic flow. The cosurfactant containing preparations were less viscous with Newtonian flow. The drug loading and release rate were increased in the presence of cosurfactants with the release depending on the viscosity. Incorporation of hydrocortisone in microemulsion increased the transdermal flux compared to saturated aqueous solution. The presence of cosurfactants increased the transdermal drug flux compared to the cosurfactant free formulation. Ethanol produced the greatest effect followed by propylene glycol and isopropanol. The presence of cosurfactant and its type can thus affect both the phase behavior and the transdermal delivery potential of microemulsion.     

Development and evaluation of a microemulsion formulation for transdermal delivery of terbinafine

The aim of the present study is to develop and evaluate microemulsion formulations for Terbinafine (TB) with a view to enhance its permeability through the skin and provide release for 24 h. Various o/w microemulsions were prepared by the spontaneous emulsification method. Oleic acid was chosen as the oil phase, Caprylo caproyl macrogol-8- glyceride (Labrasol S) and purified diethylene glycol monoethyl ether (Transcutol P) were used as surfactant and cosurfactant, respectively, on the basis of solubility studies. Pseudoternary phase diagrams were constructed to obtain the concentration range of oil, surfactant, cosurfactant, and water for microemulsion formulation. The optimized microemulsion consisted of 2% w/w TB, 8% w/w oleic acid, 31% w/w labrasol S, 31% w/w transcutol P, and 30% w/w distilled water. Permeability parameters like Jss and Kp were found to be significantly higher for formulation F4 as compared to other formulations (P < 0.05). Microbiological studies of TB in microemulsion showed better anti-fungal activity against Candida albicans and Aspergillus flavus as compared to marketed product (P < 0.05).     

The influence of cosurfactants and oils on the formation of pharmaceutical microemulsions based on PEG-8 caprylic/capric glycerides

In the present study the effect of type and concentration of a cosurfactant and oil on the ability of nonionic surfactant PEG-8 caprylic/capric glycerides (Labrasol) to solubilize both oil and water phases was evaluated. Seven different cosurfactants (polyglyceryl-6 dioleate (Plurol Oleique) (PO), polyglyceryl-6 isostearate (Plurol Isostearique (PI), polyglyceryl-4 isostearate (Isolan GI 34) (IGI34), octoxynol-12 (and) polysorbate 20 (Solubilisant gamma) 2421) (SG2421), octoxynol-12 (and) polysorbate 20 (and) PEG-40 hydrogenated castor oil (Solubilisant gamma 2429) (SG2429), PEG-40 hydrogenated castor oil (Cremophor) RH 40) (CRH40) and diethyleneglycol monoethyl ether (Transcutol) and six oils (isopropyl myristate, ethyl oleate, decyl oleate, medium chain triglycerides, mineral oil and olive oil) were used in phase behaviour studies of a quaternary system Labrasol/cosurfactant/oil/water. The amount of surfactant required to completely homogenize equal masses of oil and water to form a single phase microemulsion (termed as balanced microemulsion) (S min, %w/w), the minimal concentration of the surfactant/cosurfactant blend required to produce a balanced microemulsion (SCoS min, %w/w) as well as the maximum concentration of water solubilized in investigated surfactant/oil and surfactant/cosurfactant/oil mixtures (W(max), %w/w) were determined. The obtained results indicated that Labrasol showed a good efficiency in the presence of lower molecular volume fatty acid esters with a preferred chemical structure such as isopropyl myristate (S min 56.14% (w/w); W(max) 12.28% (w/w)). Oils with high molecular volume (olive oil and mineral oil) do not result in microemulsion formation. Transcutol decreased the capacity of Labrasol for solubilization of oil and water phases. The tendency of Labrasol to solubilize both, water and oil phases, was favoured by polyglycerol-6 ester type of cosurfactants (PO and PI) while the influence of the polyglycerol-4 ester (IGI34) as well as of polyoxyethylene type of cosurfactants (CRH40, SG2421 and SG2429) on the surfactant efficiency, was not significant. Furthermore, the results revealed the significant influence of the surfactant/cosurfactant mass ratio (K(m)) on synergistic effect between polyglyceryl-6 esters and Labrasol in the formation of microemulsions using isopropyl myristate as oil phase. Optimized microemulsion systems were stabilized with Labrasol/polyglyceryl-6 esters blend at K(m) 5:5 (SCoS min, 27.5% (w/w) and W(max), 71.43% (w/w) for PI; SCoS min, 29.18% (w/w) and W(max), 65.00% (w/w) for PO) and the electrical conductivity measurement results for optimized balanced microemulsions showed that their structures were highly conductive indicating a bicontinuous microstructure.     

Cow ghee fortified ocular topical microemulsion; in vitro,ex vivo,and in vivo evaluation

Abstract

Aim: Utility of cow ghee (CG) as permeation enhancer in development of topical ocular microemulsion (ME) for delivery of fluocinolone acetonide (FA) to posterior eye.

Methods: For ME preparation, oil, surfactant and cosurfactant were screened based on solubility of FA. Pseudoternary phase diagrams were constructed to determine their ratios. The developed MEs were characterised for their physicochemical properties like size, polydispersity index, zeta potential, and stability etc. They were evaluated for ex vivo permeation and irritation. In vivo pharmacokinetic studies were performed on Sprague dawley rats.

Results: Lauroglycol as oil, labrasol as surfactant and Transcutol as cosurfactant were selected. The optimised ratio of oil:surfactant:cosurfactant:water was 4:23:23:50. The developed FA loaded ME fortified with CG was characterised. Ex vivo study revealed higher permeation and non-irritancy. In vivo pharmacokinetic study showed retention of CG fortified ME in posterior rat eye.

Conclusion: Present investigation established CG as permeation enhancer for ocular topical formulation.     

Quality by design approach for oral bioavailability enhancement of Irbesartan by self-nanoemulsifying tablets

Abstract

The present investigation was aimed to develop self-nanoemulsifying tablets (SNETs) as novel nanosized solid oral dosage forms for Irbesartan (IRB). In the first part of the investigation, IRB-loaded self-nanoemulsifying drug delivery systems (SNEDDS) were developed using Capryol 90 – Cremophor RH40 – Transcutol P as three component (oil – surfactant – cosurfactant) SNEDDS system. On the basis of ternary phase diagram IRB-loaded SNEDDS were optimized by using Design of Experiments (DoE) and Principal component analysis (PCA) with amount of oil and surfactant: cosurfactant ratio (K_m) as factors. The optimized batch of IRB-loaded SNEDDS comprised of 31.62% w/w of Capryol 90 as oil phase, 49.90% w/w Cremophor RH40 as surfactant and 18.48% w/w of Transcutol P as cosurfactant exemplified a mean globule size as 23.94?nm. Further, with an aim to provide enhanced patient compliance the optimized batch of liquid SNEDDS was transformed into SNETs by liquisolid compaction technique. Solid state characterization of IRB-loaded liquisolid mixtures revealed a decrease in the magnitude of crystallinity of IRB. The results of in vitro drug release study of optimized batch of IRB-loaded SNET illustrated a remarkable improvement in the dissolution rate as compared to marketed tablets (Avapro® 75). The results of in vivo pharmacokinetic study on Wister rats revealed 1.78-fold enhancement in oral bioavailability for IRB-loaded SNETs against marketed tablets. The present study proposed SNEDDS as one of the suitable approach for developing nanosized solid oral dosage forms of poorly water soluble drugs like Irbesartan.     

Microemulsions as novel drug carriers: the formation,stability, applications and toxicity

A microemulsion, made from water, oil, surfactants and cosurfactant is a thermodynamically stable system. The presence of the cosurfactant is often required in order to lower the interfacial tension of this interface, because a low interfacial tension is essential for the formation of microemulsions. The transparency of microemulsions arises from their small droplet diameter. The droplet diameter in stable microemulsions is usually within the range of 10 – 140 nm. Microemulsions are graphically represented as stability areas in triangular phase diagrams where each triangular corner designates a certain component. Microemulsions are actually quaternary (pseudoternary) systems. In pharmaceutical fields, the interest in microemulsions is increasing and, thus, they are applied to various administration routes.     

Microemulsions as novel drug carriers: the formation, stability, applications and toxicity

A microemulsion, made from water, oil, surfactants and cosurfactant is a thermodynamically stable system. The presence of the cosurfactant is often required in order to lower the interfacial tension of this interface, because a low interfacial tension is essential for the formation of microemulsions. The transparency of microemulsions arises from their small droplet diameter. The droplet diameter in stable microemulsions is usually within the range of 10 - 140 nm. Microemulsions are graphically represented as stability areas in triangular phase diagrams where each triangular corner designates a certain component. Microemulsions are actually quaternary (pseudoternary) systems. In pharmaceutical fields, the interest in microemulsions is increasing and, thus, they are applied to various administration routes.     

Match of Solubility Parameters Between Oil and Surfactants as a Rational Approach for the Formulation of Microemulsion with a High Dispersed Volume of Copaiba Oil and Low Surfactant Content

Purpose

Aim was to formulate oil-in-water (O/W) microemulsion with a high volume ratio of complex natural oil, i.e. copaiba oil and low surfactant content. The strategy of formulation was based on (i) the selection of surfactants based on predictive calculations of chemical compatibility between their hydrophobic moiety and oil components and (ii) matching the HLB of the surfactants with the required HLB of the oil.

Method

Solubility parameters of the hydrophobic moiety of the surfactants and of the main components found in the oil were calculated and compared. In turn, required HLB of oils were calculated. Selection of surfactants was achieved matching their solubility parameters with those of oil components. Blends of surfactants were prepared with HLB matching the required HLB of the oils. Oil:water mixtures (15:85 and 25:75) were the titrated with surfactant blends until a microemulsion was formed.

Results

Two surfactant blends were identified from the predictive calculation approach. Microemulsions containing up to 19.6% and 13.7% of selected surfactant blends were obtained.

Conclusion

O/W microemulsions with a high volume fraction of complex natural oil and a reasonable surfactant concentration were formulated. These microemulsions can be proposed as delivery systems for the oral administration of poorly soluble drugs.