Evaluation of the Antimicrobial Activity of a Formulation Containing Ascorbic Acid and Eudragit FS 30D Microparticles for the Controlled Release of a Curcumin-Boric Acid Solid Dispersion in Turkey Poults Infected with Salmonella enteritidis: A Therapeutic Model

Abstract

The selection of components within a formulation or for treatment must stop being arbitrary and must be focused on scientific evidence that supports the inclusion of each one. Therefore, the objective of the present study was to obtain a formulation based on ascorbic acid (AA) and Eudragit FS 30D microparticles containing curcumin-boric acid (CUR-BA) considering interaction studies between the active components carried out via Fourier transform infrared spectrometry (FTIR) and differential scanning calorimetry (DSC) to minimize antagonistic effects, and comprehensively and effectively treat turkey poults infected with Salmonella enteritidis (S. enteritidis). The DSC and FTIR studies clearly demonstrated the interactions between AA, BA, and CUR. Consequently, the combination of AA with CUR and/or BA should be avoided, but not CUR and BA. Furthermore, the Eudragit FS 30D microparticles containing CUR-BA (SD CUR-BA MP) showed a limited release of CUR-BA in an acidic medium, but they were released at a pH 6.8-7.0, which reduced the interactions between CUR-BA and AA. Finally, in the S. enteritidis infection model, turkey poults treated with the combination of AA and SD CUR-BA MP presented lower counts of S. enteritidis in cecal tonsils after 10 days of treatment. These results pointed out that the use of an adequate combination of AA and CUR-BA as an integral treatment of S. enteritidis infections could be a viable option to replace the indiscriminate use of antibiotics.

Keywords: Eudragit FS 30D; S. enteritidis; ascorbic acid; boric acid; curcumin; degradation studies; interaction studies; release studies.

Figure 1

Fourier transform infrared (FTIR) spectra of (A) ascorbic acid (AA), curcumin (CUR), and AA–CUR (1:1 weight ratio); (B) boric acid (BA), CUR, and BA–CUR (1:1 weight ratio); (C) AA, BA, and AA–BA (1:1 weight ratio); and (D) AA, BA, CUR, and AA–BA–CUR (1:1:1 weight ratio).

Figure 1

Fourier transform infrared (FTIR) spectra of (A) ascorbic acid (AA), curcumin (CUR), and AA–CUR (1:1 weight ratio); (B) boric acid (BA), CUR, and BA–CUR (1:1 weight ratio); (C) AA, BA, and AA–BA (1:1 weight ratio); and (D) AA, BA, CUR, and AA–BA–CUR (1:1:1 weight ratio).

Figure 2

Differential scanning calorimetry (DSC) thermograms of (A) ascorbic acid (AA), curcumin (CUR), and AA–CUR (1:1 weight ratio); (B) boric acid (BA), CUR, and BA–CUR (1:1 weight ratio); (C) AA, BA, and AA–BA (1:1 weight ratio); and (D) AA, BA, CUR, and AA–BA–CUR (1:1:1 weight ratio).

Figure 3

Release profile of SD CUR–BA from Eudragit FS 30D microparticles (SD CUR–BA MP) at pH 5.2, 1.2, 6.8, and 7.2 at 42 °C in the flow-through dissolution apparatus (USP IV Apparatus). Data shown are the mean ± SD, n = 3.

Figure 4

Degradation profiles of SD CUR–BA at pH 5.2, 1.2 and 6.8–7.0 for 120 min at 42 °C in the USP IV apparatus, considering the following concentrations of PVP K30 in the solid dispersion: (A) 0.3 mg/mL, (B) 0.6 mg/mL, and (C) 1.2 mg/mL.

Figure 4

Degradation profiles of SD CUR–BA at pH 5.2, 1.2 and 6.8–7.0 for 120 min at 42 °C in the USP IV apparatus, considering the following concentrations of PVP K30 in the solid dispersion: (A) 0.3 mg/mL, (B) 0.6 mg/mL, and (C) 1.2 mg/mL.

Figure 5

Schematic diagram of the closed-loop configuration for the flow-through cell apparatus (USP IV Apparatus) used for the release studies of Eudragit FS 30D microparticles containing SD CUR–BA (SD CUR–BA MP) and evaluate the stability studies of SD CUR–BA.