Formulation and Evaluation of Turmeric- and Neem-Based Topical Nanoemulgel against Microbial Infection

Abstract

The combination of nanoemulgel and phytochemistry has resulted in several recent discoveries in the field of topical delivery systems. The present study aimed to prepare nanoemulgel based on turmeric (Curcuma longa) and neem (Azadirachta indica) against microbial infection as topical drug delivery. Olive oil (oil phase), Tween 80 (surfactant), and PEG600 (co-surfactant) were used for the preparation of nanoemulsion. Carbopol 934 was used as a gelling agent to convert the nanoemulsion to nanoemulgel and promote the control of the release of biological properties of turmeric and neem. The nanoemulsion was characterized based on particle size distribution, PDI values, and compatibility using FTIR analysis. In contrast, the nanoemulgel was evaluated based on pH, viscosity, spreadability, plant extract and excipient compatibility or physical state, in vitro study, ex vivo mucoadhesive study, antimicrobial properties, and stability. The resulting nanoemulsion was homogeneous and stable during the centrifugation process, with the smallest droplets and low PDI values. FTIR analysis also confirmed good compatibility and absence of phase separation between the oil substance, surfactant, and co-surfactant with both plant extracts. The improved nanoemulgel also demonstrated a smooth texture, good consistency, good pH, desired viscosity, ex vivo mucoadhesive strength with the highest spreadability, and 18 h in vitro drug release. Additionally, it exhibited better antimicrobial properties against different microbial strains. Stability studies also revealed that the product had good rheological properties and physicochemical state for a period of over 3 months. The present study affirmed that turmeric- and neem-based nanoemulgel is a promising alternative for microbial infection particularly associated with microorganisms via topical application.

Keywords: herbal plants; microbial infection; nanoemulgel; nanoemulsion; topical application.

Figure 1

Antioxidant activity of the extracts. Different superscripted letters show the statistical significance values (p-value < 0.05) at the same concentration (µg/L). Also, ascorbic acid was used as standard.

Figure 2

Anti-inflammatory activity of the extracts. Antioxidant activity of the extracts. Different superscripted letters show the statistical significance values (p-value < 0.05) at the same concentration (µg/L). Also, diclofenac sodium acid was used as standard.

Figure 3

Antimicrobial activity of the extracts.

Figure 4

Size distribution by intensity of nanoemulsion under study. (a) Nanoemulsion A1’s, which contains 2% surfactant, distribution curve. (b) Correlation coefficient of nanoemulsion A1 shows cumulant data fit. (c) Nanoemulsion B1’s, which contains 4% surfactant, distribution curve. (d) Correlation coefficient of nanoemulsion B1 that shows cumulant data fit.

Figure 5

FTIR spectra of turmeric, neem extract, Tween 80, PEG600, olive oil, nanoemulsion A1, and nanoemulsion B1. The highlighted areas represent the different focused wavenumber ranges that explained the significant differences among the studied groups.

Figure 6

Impact of polymer content on nanoemulgel viscosity and spreadability. Different superscripted letters show statistical significance values (p-value < 0.05) in same line/analysis. The highlighted dashed areas represent the overall mean confidence levels, linear trendline, and centroid points of the examinal dataset for each analysis.

Figure 7

FTIR spectra of nanoemulsion A1, nanoemulsion B1, Carbopol 934, nanoemulgel A1, and nanoemulgel B1. The highlighted areas represent the different focused wavenumber ranges that explained the significant differences among the studied groups.

Figure 8

In vitro release study of nanoemulgel. Different superscripted letters show statistical significance values (p-value < 0.05) in same time interval (min) among commercial gel, A1, and B1.

Figure 9

Antimicrobial activity of turmeric- and neem-leaf-based nanoemulgel.

Figure 10

Formulation of nanoemulsion using turmeric and neem leaf.