Formulation, Evaluation and Stability Studies of Dutasteride Loaded Niosomal Gel

Introduction: Dutasteride, a synthetic 4-azasteroid belonging to the class of 5-α-reductase, a BCS class II drug, is used in treating Androgenetic Alopecia and Benign Prostatic Hyperplasia.

Aims: The study aims to formulate, evaluate and perform stability studies of Dutasteride-loaded topical niosomal gel.

Methodology: Formulation components such as, surfactants and cholesterol were tested for any drug/excipient interactions. Ether injection method was employed to prepare Niosomes. Five formulations were prepared and then assessed for their particle size, SEM, zeta potential, PDI, entrapment efficiency, drug content and in vitro diffusion studies. The optimized formulation F3 Consisted of Dutasteride, span 40 and cholesterol in the ratio 1:4:2. The optimized formulation (F3) was incorporated into a gel. Three gel formulations (FG1, FG2 and FG3) were prepared and were assessed for pH, viscosity, spreadability, drug content and in vitro diffusion studies. The optimized niosomal gel (FG2) consisted of 0.3% Optimized Niosomes and 0.75% Carbopol 934. The drug release kinetics studies were performed for the optimized gel. Finally, stability studies were performed at 30°C ± 2°C / 65% RH ± 5%.

Results: The optimized niosomes showed an Entrapment efficiency of 63.2%, zeta potential -22.7 mV, particle size 300.4 nm, drug content 86.23% and 96.23% drug release in 8 hours. The optimized niosomal gel (FG2) consisted of 0.3% Optimized Niosomes and 0.75% Carbopol 934. The gel showed pH 4.7, viscosity 66213 cps, spreadability 15.7g.cm/sec, drug content 91.4% and percent drug release 91.45% in 24 hours. The drug release kinetics studies showed that the optimized gel formulation (FG2) followed Higuchi model with R2 value of 0.9975. The stability studies indicated that the optimized niosomal gel was stable for 90 days.

Conclusion: The stability studies confirmed the drug content and the physical nature of the gel for 90 days. Thus, the formulation can be regarded as stable and effective for drugs meant for topical application. Dutasteride gel formulations have the potential to enhance drug bioavailability by facilitating greater penetration of drugs with restricted permeability.