Introduction
Natural oil-based nanoemulsions (NEs) have been widely investigated in many diseases that affect the oral cavity. NEs are delivery systems that enhance the solubility of lipid therapeutics and improve their delivery to target sites; they are known as self-nanoemulsifying drug delivery systems (SNEDDSs). The current investigation’s aim was to produce an oregano essential oil-based nanoemulsion (OEO-SNEDD) that would have antibacterial and antifungal effects against oral microbiota and improve oral health.
Methods
Several OEO-SNEDDSs were developed using different percentages of OEO (10%, 14%, and 18%), percentages of a surfactant mixture Pluracare L64:Lauroglycol FCC (18%, 32%, and 36%), S
mix
ratios (1:2, 1:1, and 2:1), and hydrophilic-lipophilic balances (HLBs) of the surfactant mixture (8, 10, and 12) using the Box‒Behnken design. The optimized concentration of excipients was determined using a pseudoternary phase diagram to obtain the NEs. The formulations were evaluated for their droplet size, stability index, and antibacterial and antifungal activities.
Results
The NEs had a droplet size of 150 to 500 nm and stability index of 47% to 95%, and the produced formulation reached antibacterial and antifungal inhibition zones of up to 19 and 17 mm, respectively. The Box‒Behnken design was adopted to get the optimum formulation, which was 18% OEO, 36% S
mix
, 10.29 HLB of S
mix
, and a 1.25:1 S
mix
ratio. The optimized formulation had a lower ulcer index compared with various other formulations evaluated in rats.
Conclusion
This study illustrated that OEO-SNEDDSs can provide good protection against oral microbial infections.
Oral health is a key contributor to a person’s overall health and well-being. Oral microbiota can pose a serious threat to oral health. Thus, the present study aimed to develop a cinnamon oil (CO)-loaded nanoemulsion gel (NEG1) to enhance the solubilization of oil within the oral cavity, which will enhance its antibacterial, antifungal, and analgesic actions against oral microbiota. For this purpose, the CO-loaded nanoemulsion (CO-NE) was optimized using I-optimal response surface design. A mixture of Pluracare L44 and PlurolOleique CC 497 was used as the surfactant and Capryol was used as the co-surfactant. The optimized CO-NE had a globule size of 92 ± 3 nm, stability index of 95% ± 2%, and a zone of inhibition of 23 ± 1.5 mm. This optimized CO-NE formulation was converted into NEG1 using 2.5% hydroxypropyl cellulose as the gelling agent. The rheological characterizations revealed that the NEG1 formulation exhibited pseudoplastic behavior. The in vitro release of eugenol (the marker molecule for CO) from NEG1 showed an enhanced release compared with that of pure CO. The ex vivo mucosal permeation was found to be highest for NEG1 compared to the aqueous dispersion of CO-NE and pure cinnamon oil. The latency reaction time during the hot-plate test in rats was highest (45 min) for the NEG1 sample at all-time points compared with those of the other tested formulations. The results showed that the CO-NEG formulation could be beneficial in enhancing the actions of CO against oral microbiota, as well as relieving pain and improving overall oral health.
Natamycin (NT) is a synthetic broad-spectrum antifungal used in eye drops. However, it has low solubility and high molecular weight, limiting its permeation, and generally causes eye discomfort or irritation when administered. Therefore, the present study aimed to develop an ophthalmic
in situ
gel formulation with NT-loaded cubosomes to enhance ocular permeation, improve antifungal activity, and prolong the retention time within the eye. The NT-loaded cubosome (NT-Cub) formula was first optimized using an I-optimal design utilizing phytantriol, PolyMulse, and NT as the independent formulation factors and particle size, entrapment efficiency %, and inhibition zone as responses. Phytantriol was found to increase particle size and entrapment efficiency %. Higher levels of PolyMulse slightly increased the inhibition zone whereas a decrease in particle size and EE% was observed. Increasing the NT level initially increased the entrapment efficiency % and inhibition zone. The optimized NT-Cub formulation was converted into an
in situ
gel system using 1.5% Carbopol 934. The optimum formula showed a pH-sensitive increase in viscosity, favoring prolonged retention in the eye. The
in vitro
release of NT was found to be 71 ± 4% in simulated tear fluid. The optimum formulation enhanced the
ex vivo
permeation of NT by 3.3 times compared to a commercial formulation and 5.2 times compared to the NT suspension. The
in vivo
ocular irritation test proved that the optimum formulation is less irritating than a commercial formulation of NT. This further implies that the developed formulation produces less ocular irritation and can reduce the required frequency of administration.
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