Transdermal delivery of anticancer drug caffeine from water-in-oil nanoemulsions

Recently caffeine has been investigated for the treatment of various types of cancers upon oral administration. There is also some evidence that dermally applied caffeine can protect the skin from skin cancer caused by sun exposure. Therefore nanoemulsion formulation of caffeine for transdermal drug delivery was developed and evaluated in the present investigation. Different w/o nanoemulsion formulations of caffeine were prepared by oil phase titration method. Thermodynamically stable nanoemulsions were characterized for morphology, droplet size, viscosity and refractive index. The in vitro skin permeation studies were performed on Franz diffusion cell using rat skin as permeation membrane. The in vitro skin permeation profile of optimized formulation was compared with aqueous solution of caffeine. Significant increase in permeability parameters was observed in nanoemulsion formulations (P<0.05) as compared to aqueous solution of caffeine. The steady-state flux (J(ss)) and permeability coefficient (K(p)) for optimized nanoemulsion formulation (C12) were found to be 147.55+/-8.21 microg/cm(2)/h and 1.475 x 10(-2)+/-0.031 x 10(-2)cm/h, respectively. Enhancement ratio (E(r)) was found to be 17.37 in optimized formulation C12 compared with other formulations. Overall these results suggested that w/o nanoemulsions are good carriers for transdermal delivery of caffeine.

Skin permeation mechanism and bioavailability enhancement of celecoxib from transdermally applied nanoemulsion

BACKGROUND

Celecoxib, a selective cyclo-oxygenase-2 inhibitor has been recommended orally for the treatment of arthritis and osteoarthritis. Long term oral administration of celecoxib produces serious gastrointestinal side effects. It is a highly lipophilic, poorly soluble drug with oral bioavailability of around 40% (Capsule). Therefore the aim of the present investigation was to assess the skin permeation mechanism and bioavailability of celecoxib by transdermally applied nanoemulsion formulation. Optimized oil-in-water nanoemulsion of celecoxib was prepared by the aqueous phase titration method. Skin permeation mechanism of celecoxib from nanoemulsion was evaluated by FTIR spectral analysis, DSC thermogram, activation energy measurement and histopathological examination. The optimized nanoemulsion was subjected to pharmacokinetic (bioavailability) studies on Wistar male rats.

RESULTS

FTIR spectra and DSC thermogram of skin treated with nanoemulsion indicated that permeation occurred due to the disruption of lipid bilayers by nanoemulsion. The significant decrease in activation energy (2.373 kcal/mol) for celecoxib permeation across rat skin indicated that the stratum corneum lipid bilayers were significantly disrupted (p < 0.05). Photomicrograph of skin sample showed the disruption of lipid bilayers as distinct voids and empty spaces were visible in the epidermal region. The absorption of celecoxib through transdermally applied nanoemulsion and nanoemulsion gel resulted in 3.30 and 2.97 fold increase in bioavailability as compared to oral capsule formulation.

CONCLUSION

Results of skin permeation mechanism and pharmacokinetic studies indicated that the nanoemulsions can be successfully used as potential vehicles for enhancement of skin permeation and bioavailability of poorly soluble drugs.

Nanoemulsions as potential vehicles for transdermal and dermal delivery of hydrophobic compounds: an overview

INTRODUCTION

In recent years, nanoemulsions have been investigated as potential drug delivery vehicles for transdermal and dermal delivery of many compounds especially hydrophobic compounds in order to avoid clinical adverse effects associated with oral delivery of the same compounds. Droplet size and surface properties of nanoemulsions play an important role in the biological behavior of the formulation.

AREAS COVERED

In this review, current literature of transdermal and dermal delivery of hydrophobic compounds both in vitro as well as in vivo has been summarized and analyzed.

EXPERT OPINION

Nanoemulsions have been formulated using a variety of pharmaceutically acceptable excipients. In many cases of dermal and transdermal nanoemulsions, the skin irritation or skin toxicity issues on human beings have not been considered which needs to be evaluated properly. In the last decade, much attention has been made in exploring new types of nanoemulsion-based drug delivery system for dermal and transdermal delivery of many hydrophobic compounds. This area of research would be very advantageous for formulation scientists in order to develop some nanoemulsion-based formulations for their commercial exploitation and clinical applications.

Solubility and thermodynamic function of vanillin in ten different environmentally benign solvents

The solubility of vanillin in ten different environmentally benign solvents namely water, ethanol, ethylene glycol (EG), ethyl acetate (EA), isopropanol (IPA), propylene glycol (PG), polyethylene glycol-400 (PEG-400), Transcutol, butanol-1 and butanol-2 was measured and correlated at T=(298-318)K. The resulting experimental data were correlated with the modified Apelblat and Van't Hoff models. Both the models showed good correlation of experimental solubility data with calculated ones with root mean square deviations in the range of (0.08-1.55)%. The mole fraction solubility of vanillin was observed highest in PEG-400 (4.29 × 10(-1) at 298 K) followed by Transcutol, EA, butanol-2, ethanol, EG, PG, IPA, butanol-1 and water from T=(298-318)K. The results of thermodynamic function in terms of dissolution enthalpy, Gibbs energy and dissolution entropy showed endothermic, spontaneous and entropy-driven dissolution of vanillin in all environmentally benign solvents.

Celecoxib nanoemulsion: skin permeation mechanism and bioavailability assessment

The aim of the present study was to assess the skin permeation mechanism and bioavailability of celecoxib (CXB) using novel nanoemulsion formulation. Fourier transform infrared spectra and differential scanning calorimetric thermogram of skin treated with nanoemulsion indicated that permeation occurred due to the extraction of stratum corneum (SC) lipids by nanoemulsion. The significant decrease in activation energy for CXB permeation across rat skin indicated that the SC lipid bilayers were significantly disrupted (p < 0.05). Photomicrograph of skin sample showed the disruption and extraction of lipid bilayers as distinct voids and empty spaces visible in the epidermal region. The absorption of CXB through transdermally applied nanoemulsion and nanoemulsion gel resulted in 3.03- and 2.65-fold increases in bioavailability when compared with conventional oral capsule formulation. Overall, these findings indicated that nanoemulsions can be successfully used for the enhancement of skin permeation and bioavailability of poorly soluble drugs.

Investigation of true nanoemulsions for transdermal potential of indomethacin: characterization, rheological characteristics, and ex vivo skin permeation studies

The aim of the present study was to investigate the potential of true nanoemulsions for transdermal delivery of indomethacin. Thermodynamically stable true nanoemulsions were characterized for morphology using transmission electron microscopy (TEM), droplet size, rheological characteristics, and refractive index. The rheological behavior for all true nanoemulsions was found to be Newtonian as viscosity was unchanged by increasing the rate of shear. The ex vivo skin permeation studies were performed using Franz diffusion cell with rat skin as permeation membrane. The ex vivo skin permeation profile of optimized formulation was compared with marketed Indobene gel and nanoemulsion gel. Significant increase in permeability parameters was observed in nanoemulsion formulations (P < 0.05). The steady-state flux (J(ss)) and permeability coefficient (K(p)) for optimized nanoemulsion formulation were found to be 73.96 +/- 2.89 mug/cm(2)/h and 1.479 x 10(-2) +/- 0.289 x 10(- 2 )cm/h, respectively, which were significant compared with Indobene gel and nanoemulsion gel (P < 0.05). Enhancement ratio (E(r)) was found to be 7.88 in optimized formulation F6 compared with other formulations. These results suggested that nanoemulsions can be used as potential vehicles for improved transdermal delivery of indomethacin.

Bioavailability enhancement and pharmacokinetic profile of an anticancer drug ibrutinib by self-nanoemulsifying drug delivery system

OBJECTIVE

The current studies were undertaken to enhance dissolution and bioavailability/pharmacokinetic profile of a newly approved anticancer drug ibrutinib (IBR) via encapsulation of drug into self-nanoemulsifying drug delivery system (SNEDDS).

METHODS

Various SNEDDS formulations of IBR were developed by aqueous phase titration method using Capryol-PGMC (oil phase), Tween-20 (surfactant), Carbitol (cosurfactant) and water (aqueous phase). Developed SNEDDS of IBR was evaluated in vitro for various physicochemical properties and drug release profile.

KEY FINDINGS

Based on lowest droplet size (28.7 ± 3.2 nm), least polydispersity (0.123), optimal values of zeta potential (-32.8 mV) and refractive index (1.336), highest % transmittance (98.7 ± 0.2%), highest drug release profile via dialysis membrane (98.9 ± 8.2% after 48 h) and the presence of lowest concentration of Capryol-PGMC (12% w/w), SNEDDS I1 was selected for in-vivo pharmacokinetic/bioavailability studies in female Wistar rats. In-vivo pharmacokinetic studies in rats showed that optimized SNEDDS I1 controlled the absorption of IBR compared with IBR suspension. The bioavailability of IBR from optimized SNEDDS I1 was enhanced around 2.64 times in comparison with IBR suspension.

CONCLUSION

These results indicated the potential of developed SNEDDS as an alternative drug delivery system for IBR to enhance its bioavailability and anticancer efficacy.

Solubility and thermodynamic behavior of vanillin in propane-1,2-diol+water cosolvent mixtures at different temperatures

The solubilities of bioactive compound vanillin were measured in various propane-1,2-diol+water cosolvent mixtures at T=(298-318)K and p=0.1 MPa. The experimental solubility of crystalline vanillin was determined and correlated with calculated solubility. The results showed good correlation of experimental solubilities of crystalline vanillin with calculated ones. The mole fraction solubility of crystalline vanillin was recorded highest in pure propane-1,2-diol (7.06×10(-2) at 298 K) and lowest in pure water (1.25×10(-3) at 298 K) over the entire temperature range investigated. Thermodynamic behavior of vanillin in various propane-1,2-diol+water cosolvent mixtures was evaluated by Van't Hoff and Krug analysis. The results showed an endothermic, spontaneous and an entropy-driven dissolution of crystalline vanillin in all propane-1,2-diol+water cosolvent mixtures. Based on solubility data of this work, vanillin has been considered as soluble in water and freely soluble in propane-1,2-diol.

Experimental and Computational Approaches for Solubility Measurement of Pyridazinone Derivative in Binary (DMSO + Water) Systems

The current research work was performed to evaluate the solubilization behavior, solution thermodynamics, and solvation behavior of poorly soluble pyridazinone derivative i.e., 6-phenyl-pyridazin-3(2H)-one (PPD) in various binary solvent systems of dimethyl sulfoxide (DMSO) and water using experimental and various computational approaches. The solubility of PPD in various binary solvent system of DMSO and water was investigated within the temperature range T = 298.2 K to 318.2 K at constant air pressure p = 0.1 MPa, by employing an isothermal technique. The generated solubility data of PPD was computationally represented by five different cosolvency models including van't Hoff, Apelblat, Yalkowsky-Roseman, Jouyban-Acree, and Jouyban-Acree-van't Hoff models. The performance of each computational model for correlation studies was illustrated using root mean square deviations (RMSD). The overall RMSD value was obtained <2.0% for each computational model. The maximum solubility of PPD in mole fraction was recorded in neat DMSO (4.67 × 10-1 at T = 318.2 K), whereas the lowest one was obtained in neat water (5.82 × 10-6 at T = 298.2 K). The experimental solubility of PPD in mole fraction in neat DMSO was much higher than its ideal solubility, indicating the potential of DMSO for solubility enhancement of PPD. The computed values of activity coefficients showed maximum molecular interaction in PPD-DMSO compared with PPD-water. Thermodynamic evaluation showed an endothermic and entropy-driven dissolution of PPD in all the mixtures of DMSO and water. Additionally, enthalpy-entropy compensation evaluation indicated an enthalpy-driven mechanism as a driven mechanism for the solvation property of PPD.

Nanoemulsion: a promising tool for solubility and dissolution enhancement of celecoxib

The solubility and dissolution of the poorly soluble drug celecoxib (CXB) was enhanced using many techniques like nanoemulsion, solid lipid nanoparticle and solid dispersion in the present investigation. The solubility of CXB in each formulation was determined using the reported HPLC method at the wavelength of 250 nm. Dissolution studies of pure CXB and its formulations were performed using USP dissolution apparatus in distilled water. The highest solubility (228. 24 mg/mL) as well as % dissolution (99.9) of CXB was obtained with nanoemulsion technique. The results of solubility and dissolution were highly significant using the nanoemulsion technique as compared to other techniques (P < 0.01). All three formulations showed a sustained type of drug release. The best sustained type drug release was obtained with nanoemulsion. This indicated that nanoemulsion can be successfully used for sustained and controlled drug delivery of CXB. Overall these findings suggested that nanoemulsion is a promising vehicle for solubility and dissolution enhancement of CXB.

Chemoprevention of skin cancer using low HLB surfactant nanoemulsion of 5-fluorouracil: a preliminary study

Oral delivery of 5-fluorouracil (5-FU) is difficult due to its serious adverse effects and extremely low bioavailability. Therefore, the aim of present investigation was to develop and evaluate low HLB surfactant nanoemulsion of 5-FU for topical chemoprevention of skin cancer. Low HLB surfactant nanoemulsions were prepared by oil phase titration method. Thermodynamically stable nanoemulsions were characterized in terms of droplet size distribution, zeta potential, viscosity and refractive index. Selected formulations and control were subjected to in vitro skin permeation studies through rat skin using Franz diffusion cells. Optimized formulation F9 was subjected to stability and in vitro cytotoxic studies on melanoma cell lines. Enhancement ratio was found to be 22.33 in formulation F9 compared with control and other formulations. The values of steady state flux and permeability coefficient for formulation F9 were found to be 206.40 ± 14.56 µg cm(-2) h(-1) and 2.064 × 10(-2) ± 0.050 × 10(-2 )cm h(-1), respectively. Optimized formulation F9 was found to be physical stable. In vitro cytotoxicity studies on SK-MEL-5 cancer cells indicated that 5-FU in optimized nanoemulsion is much more efficacious than free 5-FU. From these results, it can be concluded that the developed nanoemulsion might be a promising vehicle for chemoprevention of skin cancer.