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Medically, the oil-in-water nanosized emulsions are used mainly as delivery carriers for lipophilic drug molecules which show therapeutic activity when administered via parenteral, ocular and transdermal routes. To extract multifunctional activities, the nanosized emulsions containing neutral, anionic and cationic charges over dispersed oil droplets are designed with the help of variety of excipients especially emulsifiers. This type of decoration on the dispersed oil droplet’s surface allows the nanosized emulsions to be useful for drug delivery and/or drug targeting to otherwise inaccessible internal organs of human body. The aim of this review is to address the various manufacturing techniques and excipients used during the formulation of the multifunctional o/w nanosized emulsions for medical applications.

Medically, the oil-in-water nanosized emulsions are used mainly as delivery carriers for lipophilic drug molecules which show therapeutic activity when administered via parenteral, ocular and transdermal routes. To extract multifunctional activities, the nanosized emulsions containing neutral, anionic and cationic charges over dispersed oil droplets are designed with the help of variety of excipients especially emulsifiers. This type of decoration on the dispersed oil droplet’s surface allows the nanosized emulsions to be useful for drug delivery and/or drug targeting to otherwise inaccessible internal organs of human body. The aim of this review is to address the various manufacturing techniques and excipients used during the formulation of the multifunctional o/w nanosized emulsions for medical applications.

Aim: To investigate eutectic liquid-based emulsion-like dispersions for intratympanic injections to augment cinnarizine permeability across round window membrane in a healthy rabbit inner ear model. Methods: Two-tier systematic optimization was used to get the injection formula. The drug concentrations in perilymph and plasma were analyzed via. Ultra-performance liquid chromatography-tandem mass spectrometry method after 30-, 60-, 90- and 120-min post intratympanic injection time points in rabbits. Results: A shear-thinning behavior, immediate drug release (∼98.80%, 10 min) and higher cell viability (>97.86%, 24 h) were observed in dispersions. The cinnarizine level of 8168.57 ± 1236.79 ng/ml was observed in perilymph at 30 min post intratympanic injection in rabbits. Conclusion: The emulsion-like dispersions can augment drug permeability through round window membrane. Article highlights Intratympanic injections containing cinnarizine-loaded emulsion-like dispersions was prepared using camphor-menthol (1:0.97 molar ratio) eutectic liquid. The formula for preparing cinnarizine-loaded emulsion-like dispersions was obtained by applying linear (response surface methodology) and non-linear (artificial neural network) models. The optimized cinnarizine-loaded emulsion-like dispersions was prepared as per the formula suggested by the non-linear model. The MPS, PDI, ZP and drug amount in whole dispersions values of drug-loaded emulsion-like dispersions were 175.40 ± 5.20 nm, 0.245 ± 0.018, 43.20 ± 3.30 mV and 72.37 ± 5.67% w/v, respectively. The DEE, pH and osmolality values of drug-loaded emulsion-like dispersions prepared using the optimized formula were 96.50 ± 0.44%, 7.40 ± 0.07 and 299 ± 42.29 mOsm/kg H2O, respectively. The emulsion-like dispersions were found to be shear thinning (0.1 to 100 s-1 shear rate) and was not affected by coalescence and Ostwald ripening till 90 days at 25°C. The MTT test results performed in L-929 cells displayed cell viability values of more than 97.86% for all tested concentrations of drug-loaded emulsion-like dispersions. The presence of cinnarizine in perilymph and plasma of healthy rabbit inner ear model after intratympanic administration of drug-loaded emulsion-like dispersions was checked using a UPLC-MS/MS bioanalytical method. The intratympanic administration of drug-loaded emulsion-like dispersions displayed cinnarizine concentrations of 470.10 to 8168.57 ng/ml in perilymph for 30–120 min. [ABSTRACT FROM AUTHOR]

Background: To prepare ocular emulsions containing bipartitioned oil droplets to entrap cyclosporin A (0.05% w/w) and etodolac (0.2% w/w) by using castor, olive and silicon oils. Methods: The physicochemical characterizations of prepared emulsions were performed. The drug's biodistribution profiles and pharmacokinetic parameters from emulsions were checked using the ultraperformance liquid chromatography–tandem mass spectrometry method in the ocular tissues of the healthy rabbit eye model. Results: The emulsions displayed 365.13 ± 7.21 nm size and 26.45 ± 2.09 mV zeta potential. The ferrying of two drugs after releasing from emulsions occurred across corneal/conjunctival tissues to enter the vitreous and sclera following a single drop administration into the rabbit's eyes. Conclusion: The dual drug-loaded emulsions were more likely to produce synergistic anti-inflammatory activity for managing moderate-to-severe dry eye disease. Summary points Ocular emulsion eyedrops containing bipartitioned oil droplets to entrap cyclosporin A (CsA) and etodolac (Edc) were prepared using castor, olive and silicon oils. The mean particle size, polydispersity index and zeta potential values observed for emulsions were 365.13 ± 7.21 nm, 0.282 ± 0.03 and 26.45 ± 2.09 mV, respectively. The drug-entrapment efficiency values of 77–82% were found for CsA and Edc in emulsions. A faster Edc release from emulsions was observed compared with CsA release in 7.4 pH simulated tear fluid. The combination index value of 0.806 computed from the in vitro protein denaturation assay indicates synergism in the anti-inflammatory activity of emulsions. The cell viability (%) values of 95.710 ± 2.78 to 99.263 ± 0.92% were noticed in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay using human corneal epithelial cells. The ultraperformance liquid chromatography–tandem mass spectrometry bioanalytical method was utilized for the simultaneous estimation of CsA and Edc in ocular tissues of healthy rabbit eyes. The highest area under the curve from 0 to 90 min time period (AUC0-90 min) values were obtained for CsA from emulsions in the cornea followed by conjunctiva, sclera, vitreous and aqueous humor. The highest AUC0-90 min values were found for Edc from emulsion in the cornea, followed by the sclera, conjunctiva, aqueous humor and vitreous. [ABSTRACT FROM AUTHOR]

A design of experiments (DoE)-driven RP-HPLC method conditions was employed to analyze simultaneously chloroquine (CQ) phosphate and flavopiridol (FLAP) in emulsions and solution. After subjecting the various critical method attributes to preliminary risk assessment and screening by Pareto-chart-based fractional factorial design, the 17 runs were produced in Box–Behnken design for optimization. Analysis of variance, lack of fit, prediction equations, 3D response surface plots and contour plots were used to evaluate the critical analytical attributes such as retention time, tailing factor and theoretical plate count. The optimized RP-HPLC method conditions include 262 nm as detection wavelength, 37°C temperature for column, 20-μl injection volume, 1-ml/min flow rate and mobile phase mixture [70:30 ratio of 0.4% triethylamine in methanol&sodium phosphate buffer (11 mM, pH 3.0)]. The studied validation parameters were found within the ICH–prescribed limits. Exposing the combined drug solution at oxidative stress condition resulted to diminish the FLAP recovery value (53.39 ± 0.86) and arrival of an extra chromatographic peak. However, the % drug entrapment efficiency values of 96.22 ± 2.47 and 85.86 ± 3.66, respectively, were noticed for CQ phosphate and FLAP in emulsions. Thus, DoE-driven approach could be helpful for systematically optimizing RP-HPLC method conditions. [ABSTRACT FROM AUTHOR]