Study of Effect of Variables on Particle Size of Telmisartan Nanosuspensions Using Box-Behnken Design

Nanosuspension coated multiparticulates for controlled delivery of albendazole

OBJECTIVE

Improving solubility and bioavailability of albendazole (ALB).

SIGNIFICANCE

ALB is a broad-spectrum anthelminthic BCS class II drug with aqueous solubility of solubility of 4.1 mg/l at 25 °C and oral bioavailability of <5%.

METHODS

ALB nanosuspensions (NSs) were prepared by evaporative antisolvent precipitation using tocopherol polyethylene glycol succinate (TPGS) and polyvinyl pyrrolidone (PVP) as stabilizers and characterized for particle size, polydispersity index, and zeta potential. 3² factorial design was used to investigate effect of stabilizer concentration and speed of stirring on particle size. Concentration of TPGS was varied from 0.03 to 0.05% w/v and PVP K-30 was constant at 0.04% w/v. Stirring speed range was 1000-3000 rpm. Optimized NS was loaded on Espheres and coated with Eudragit S10& L100 and studied for friability, surface morphology and release kinetics.

RESULTS

Factorial experiments revealed pronounced effect of TPGS on particle size. Optimized batch had particle size of 251 ± 7.2 nm and zeta potential -16.2 ± 2.68 mV. Saturation solubility showed increase of 16-fold in water whereas in phosphate buffer increase was fourfold. ALB-NS secondary coated Espheres released 94.3% drug in 10 h whereas ALB-MS (microsuspension) coated Espheres showed 58% release. A 1.3-fold increase in AUC_0-10h was evident. Permeation from ALB-NS coated Espheres was 32% in 60 min while for ALB-MS coated Espheres it was 20%. Permeation increase occurred due to presence of TPGS which acts as a permeation enhancer.

A Design of Experiment (DoE) based approach for development and optimization of nanosuspensions of telmisartan, a BCS class II antihypertensive drug

Background

The present study was aimed to enhance the solubility and dissolution of BCS class II drug, telmisartan (TEM), by nanoformulation approach. Several attempts were made to develop a nanosuspension by bottom-up and top-down techniques. In our study, we found in situ nanoamorphization technique to be incompatible and hence was not selected for further development of nanoformulation. Bottom-up techniques such as anti-solvent precipitation and emulsification solvent evaporation methods failed to reduce the size of the drug to nanoform by HPMC E15 and PVP K-25 at 1500–2000 rpm but resulted in micron-sized particles.

Results

However, the acid-base neutralization method has produced nanosuspension with a particle size of 243.9 nm and 0.119 PDI. Formulation and analytical development were carried out by statistical factorial design using the Design-Expert software (version 11.0). The nanosuspensions remained stable even after 90 days without any aggregations with particle size 338.1 nm and PDI 0.146. Zeta potential of optimized formulation was found to be − 16.2 mV. Drug content and its release were estimated by the developed and validated in-house HPLC method. In vitro drug diffusion studies on the optimized formulation have shown a drug release of 82.6% by the end of 3 h, whereas plain drug suspension has shown only 42.8% release, indicating a 2-fold increase of drug diffusion with nanosuspension. Ex vivo drug permeation studies performed using excised goat gastric mucosa revealed much faster permeation of TEM from nanosuspension than the plain drug suspension.

Conclusions

Hence, from the results, it can be concluded that TEM, when formulated by acid-base neutralization method as a nanosuspension, leads to enhanced solubility, dissolution, and stability.

Preparation and in vivo/in vitro evaluation of formononetin phospholipid/vitamin E TPGS micelles

To enhance the formononetin (FN) antitumor effect, we developed a passive targeting FN-contained formulation. FN-contained Vitamin E d-α-tocopheryl polyethylene glycol 1000 succinate (vitamin E TPGS or TPGS)/phospholipid micelles were prepared by the solvent injection method. Particle size, polydispersity, zeta potential, encapsulation efficiency, drug release profile, and micelles morphology were evaluated and characterized by various methods including high-performance liquid chromatography, dynamic light scattering, and transmission electron microscopy. Cellular uptake of micelles was evaluated with fluorescence imaging coupled with HPLC method. Cytotoxicity of FN micelles and free FN was compared using MTT method. In vivo imaging was employed to assess the accumulation of DiR micelles and free DiR at tumor site. The antitumor effect of FN micelles was examined in tumor-bearing mice. The results showed that prepared FN micelles had an average particle diameter of 111.91 ± 5.82 nm with good stability. FN micelles enhanced the cellular uptake and improved cell cytotoxicity than free FN. Furthermore, DiR micelles quickly accumulated at the tumor site than free DiR. FN micelles significantly improved tumor inhibition rate compared to that observed with free FN in tumor-bearing mice with great biosafety. Thus, FN micelles demonstrated a clear treatment advantage and provided an ideal drug administration system to improve the antitumor effect of FN.