Nazrul Haq

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.

Application of Carbon Nanotubes in Heavy Metals Remediation

Carbon nanotubes (CNTs) are the engineered nanomaterial that has a very simple chemical composition and structure. Extremely high aspect ratios, molecularly smooth hydrophobic graphitic walls, and nanoscale inner diameters of CNTs give rise to the peculiar adsorption properties. This review provides an overview on CNTs functionalization and their application as an adsorbent for scavenging heavy metals and radionuclide from wastewater systems. A summary of recent information obtained using batch studies and deals with mechanisms involved during the adsorption have been reported. Adsorption capacity of CNTs has been observed by numerous investigators to increase substantially after functionalization/treatment with oxidizing agents such as NaOCl, HNO3, H2SO4, KMnO4, and other oxidizing agents. However, the selectivity of CNTs toward metal ions depends on both the route used for their synthesis and reagent employed for purification. The recovery of metal ions and the regeneration of CNTs have minimal impact on their performance. Desorption of metal ions from saturated adsorbent can be achieved using acid/base elution.

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

Abstract 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.

Thermodynamics-based mathematical model for solubility prediction of glibenclamide in ethanol–water mixtures

Abstract Temperature-dependent solubility data of glibenclamide (GBN) in various ethanol–water mixtures is not reported in literature so far. Therefore, the aim of this study was to determine the mole fraction solubility of GBN in various ethanol–water mixtures at the temperature range of 293.15 to 318.15 K. The solubility of GBN was determined by reported shake flask method and the experimental data was fitted in thermodynamics-based modified Apelblat model. The solubility of GBN was found to be increased with increase in temperature and mass fraction of ethanol in ethanol–water mixtures. The experimental data of GBN was well correlated with the modified Apelblat model at each temperature range with correlation coefficient of 0.9940–1.0000. The relative absolute deviation (AD) was found to be less than 0.1% except in pure ethanol and water. The positive values of enthalpies and entropies for GBN dissolution indicated that its dissolution is endothermic and an entropy-driven process.

Surface-adsorbed reverse micelle-loaded solid self-nanoemulsifying drug delivery system of talinolol

Abstract The aim of present investigation was to develop surface-adsorbed reverse-micelle-loaded solid self-nanoemulsifying drug delivery system (SNEDDS) of talinolol in order to enhance its in vitro dissolution rate, which in turn enhance the bioavailability. SNEDDS were prepared using aqueous phase titration method. Thermodynamically stable formulations were characterized in terms of droplet size, viscosity, % transmittance, drug content and surface morphology. Low cost acid-treated coffee husk was used as an effective biosorbent for preparation of solid SNEDDS. Developed SNEDDS were subjected to in vitro drug release/dissolution studies. In vitro drug release studies showed 99.6% release of talinolol from optimized solid SNEDDS TS3 after 120 min of study. The results of solubility studies showed 4849.5-folds enhancement in solubility of talinolol from optimized SNEDDS as compared to its aqueous solubility.

AN ENVIRONMENTALLY BENIGN APPROACH FOR RAPID ANALYSIS OF INDOMETHACIN USING A STABILITY-INDICATING RP-HPLC METHOD

A green RP-HPLC method for analysis of indomethacin (IND) in bulk drug, nanoemulsions, and various marketed formulations was developed and validated in the present investigation. The chromatographic identification was achieved on a Lichrosphere 250 × 4.0 mm RP C8 column having a 5-µm packing as a stationary phase using a green solvent ethyl acetate (100% v/v) as a mobile phase, at a flow rate of 1.0 mL/min with UV detection at 318 nm. The proposed method was validated for linearity, selectivity, accuracy, precision, robustness, sensitivity, and specificity. The utility of the method was verified by assay of IND in developed nanoemulsion, marketed tablet, capsule, suppository, and injection. The proposed method was found to be selective, precise, accurate, robust, sensitive, and specific. The amount of IND in developed nanoemulsion and all marketed formulations ranged from 98.34–101.40%. The proposed method successfully resolved IND peak in the presence of its degradation products which indicates the stability-indicating property of the proposed method. These results indicate that the proposed method can be successfully employed for routine analysis of IND in bulk drug and pharmaceutical dosage forms.

Potential of lipid nanoemulsion for drug delivery of cholesteryl-hexahydrophthaloyl-5-fluorouracil

The present study was undertaken to evaluate lipid nanoemulsions of cholesteryl-hexahydrophthaloyl-5-fluorouracil (CHHP-5-FU) to improve its therapeutic potential and to reduce adverse effects. CHHP-5-FU-loaded lipid nanoemulsions were prepared by high energy emulsification method and evaluated for droplet size, polydispersity index, zeta potential, refractive index and drug release. The drug release was found to be increased significantly by increasing the concentration of surfactants and decreasing droplet size & viscosity of formulations (P

Thermodynamic modeling for solubility prediction of indomethacin in self-nanoemulsifying drug delivery system (SNEDDS) and its individual components

Abstract For the development of an effective self-nanoemulsifying drug delivery system (SNEDDS) of poorly soluble drugs, the knowledge of the solubility in its oil phase and SNEDDS are one of the most important factors to avoid possibility of drug to get phase separated or precipitated upon dilution with gastrointestinal fluids. With this background, this study was undertaken to determine the equilibrium saturated solubility as well as mole fraction solubility of indomethacin in prepared SNEDDS and its individual components at the temperature range of 295.15 to 320.15 K. The equilibrium solubilities of indomethacin in each sample matrices were determined by an isothermal mechanical shaking method and the resulting data was analyzed by regression analysis. The experimental mole fraction solubility data of indomethacin at various temperatures was well correlated with the modified Apelblat model. The equilibrium saturated solubility as well as mole fraction solubility of indomethacin was found to be increased with increase in temperature in SNEDDS as well as in its individual components. The mole fraction solubility of indomethacin was found to be significantly higher in Tween-80 than SNEDDS, Labrafil-M1944CS and Transcutol-HP. These preliminary studies on solubility could be a useful tool for the development of an efficient and thermodynamically stable SNEDDS formulation of various poorly soluble drugs to enhance their solubility/dissolution and oral bioavailability.

Formulation and evaluation of cholesterol-rich nanoemulsion (LDE) for drug delivery potential of cholesteryl-maleoyl-5-fluorouracil

Abstract It has been reported that cholesterol-rich nanoemulsions (LDE) can bind to low density lipoprotein (LDL) receptors which can concentrate anticancer drugs in the tissues via LDL receptor overexpression and reduced the adverse effects of the treatment. Therefore, in this study, LDE nanoemulsions of cholesteryl-maleoyl-5-fluorouracil (5-FU conjugate) were developed and evaluated in vitro. LDE nanoemulsions were prepared by high-energy emulsification technique. Developed formulations were characterized in terms of droplet size, polydispersity index, zeta potential, viscosity and refractive index. Optimized formulation (L5) was also evaluated for surface morphology using transmission electron microscopy (TEM). Developed formulations were subjected to in vitro drug release studies through dialysis membrane. The droplet size (50 nm), polydispersity index (0.109) and viscosity (32.16 cp) were found to be lowest for optimized formulation L5. The results of zeta potential indicated the stable formation of developed LDE nanoemulsions. TEM images of optimized formulation indicated non-spherical shape of droplets. About 97% of conjugate was found to be released from L5 after 24 h of study. Overall, these results indicated that developed LDE nanoemulsions could be successfully used for oral delivery of 5-FU conjugate.

Self-nanoemulsifying performance of two grades of Lauroglycol (Lauroglycol-90 and Lauroglycol-FCC) in the presence of mixed nonionic surfactants

Abstract The present study was undertaken to evaluate the impact of various combinations of nonionic surfactants on self-nanoemulsifying performance of two grades of Lauroglycol (Lauroglycol-90 and Lauroglycol-FCC) in glibenclamide (GBN) nanoemulsion. Formulations (L1–L30) were prepared by spontaneous emulsification method. Prepared formulations were subjected to thermodynamic stability and self-nanoemulsification test. Results of thermodynamic stability and self-nanoemulsification tests were confirmed by further characterization of these formulations in terms of droplet size, viscosity, refractive index and % transmittance. Formulations prepared with Labrasol, HCO-60 and Gelucire-44/14 were found to be suitable for self-emulsifying drug delivery system only whereas those prepared with Tween-80 and Cremophor-EL were found to be suitable for self-nanoemulsifying or self-microemulsifying drug delivery system of GBN with respect to Lauroglycol-90 or Lauroglycol-FCC. Formulation L24 (Lauroglycol-FCC/Tween-80/ethanol/water) was optimized as best formulation for self-nanoemulsifying drug delivery system of GBN. These results indicated that Tween-80 could be the best surfactant in terms of self-nanoemulsification.