Self-Nanoemulsifying Drug Delivery System (SNEDDS) for Improved Oral Bioavailability of Chlorpromazine: In Vitro and In Vivo Evaluation

Background and Objectives: Lipid-based self-nanoemulsifying drug delivery systems (SNEDDS) have resurged the eminence of nanoemulsions by modest adjustments and offer many valuable opportunities in drug delivery. Chlorpromazine, an antipsychotic agent with poor aqueous solubility—with extensive first-pass metabolism—can be a suitable candidate for the development of SNEDDS. The current study was designed to develop triglyceride-based SNEDDS of chlorpromazine to achieve improved solubility, stability, and oral bioavailability. Materials and Methods: Fifteen SNEDDS formulations of each short, medium, and long chain, triglycerides were synthesized and characterized to achieve optimized formulation. The optimized formulation was characterized for several in vitro and in vivo parameters. Results: Particle size, zeta potential, and drug loading of the optimized SNEDDS (LCT14) were found to be 178 ± 16, −21.4, and 85.5%, respectively. Long chain triglyceride (LCT14) showed a 1.5-fold increased elimination half-life (p < 0.01), up to 6-fold increased oral bioavailability, and 1.7-fold decreased plasma clearance rate (p < 0.01) compared to a drug suspension. Conclusion: The findings suggest that SNEDDS based on long-chain triglycerides (LCT14) formulations seem to be a promising alternative for improving the oral bioavailability of chlorpromazine

Sensitivity of <i>C. glutamicum</i> strains to various classes of antibiotics tested by disk diffusion assay.

<p>**<i>P</i>≤0.01 versus wild type for the mutants.</p>a<p>The values are mean±SD for three independent determinations.</p><p>Sensitivity of <i>C. glutamicum</i> strains to various classes of antibiotics tested by disk diffusion assay.</p

Michaelis-Menten parameters of Mca for <i>N</i>-deacetylation of GlcNAc and for amidase activity of MSmB.

a<p>Assays were performed using 10 µM enzyme and 0–10 mM MSmB in 50 mM HEPES (pH 7.5) at 37°C.</p>b<p>Assays were performed in the presence of 10 µM enzyme and 0–5.0 mM GlcNAc in 50 mM HEPES (pH 7.5) at 30°C.</p><p>Michaelis-Menten parameters of Mca for <i>N</i>-deacetylation of GlcNAc and for amidase activity of MSmB.</p

Sensitivity of <i>C</i>. <i>glutamicum</i> strains to oxidizing and reducing agents tested by disk diffusion assay.

<p>**<i>P</i>≤0.01 versus wild type for the mutant.</p>a<p>The values are mean±SD for three independent determinations.</p><p>Sensitivity of <i>C</i>. <i>glutamicum</i> strains to oxidizing and reducing agents tested by disk diffusion assay.</p

The minimum inhibitory concentrations (MICs) of various antibiotics for <i>C</i>. <i>glutamicum</i> strains.

<p>**<i>P</i>≤0.01 versus wild type for the mutants.</p>a<p>The values are mean±SD for three independent determinations.</p><p>The minimum inhibitory concentrations (MICs) of various antibiotics for <i>C</i>. <i>glutamicum</i> strains.</p

Effects of divalent metal cations and pH on <i>C. glutamicum</i> Mca activity.

<p><b>A–E.</b> Catalytic activity of Mca in the presence of Co²⁺(A), Mn²⁺(B), Ni²⁺(C), Zn²⁺(D) and Fe²⁺(E), respectively, was analyzed with GlcNAc or MSmB as substrates. Apo-Mca was incubated with stoichiometric amounts of metal ions. After 30 min, the enzyme was diluted into assay buffer containing the substrate GlcNAc (5 mM) or MSmB (1 mM). The amidase activity (Left Y axis) and deacetylase activity (Right Y axis) were measured as described in “Materials and Methods”. <b>F.</b> Deacetylation of GlcNAc and amidase activity of MSmB by Zn²⁺-Mca at different pH levels. The <i>V/K</i> values were measured with 5 mM GlcNAc as substrate for deacetylase activity (Left Y axis) or 1 mM MSmB as substrate for amidase activity (Right Y axis) under six different pH values. <i>pK</i>_a values of 6.5 and 9.5 were determined by fitting <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0115075#pone.0115075.e001" target="_blank">Equation 1</a> to the data (bars represent standard error of the mean).</p

Steady-state kinetic parameters of <i>C. glutamicum</i> Mca mutants for <i>N</i>-deacetylation of <i>N</i>-acetyl-D-glucosamine (GlcNAc).

<p>Assays were performed in the presence of 10 µM enzyme and 0–5.0 mM GlcNAc in 50 mM HEPES (pH 7.5) at 30°C.</p><p>Steady-state kinetic parameters of <i>C. glutamicum</i> Mca mutants for <i>N</i>-deacetylation of <i>N</i>-acetyl-D-glucosamine (GlcNAc).</p

Steady-state kinetic parameters of <i>C. glutamicum</i> Mca mutants for amidase activity of mycothiol bimane (MSmB).

<p>Assays were performed using 10 µM enzyme and 0–10 mM MSmB in 50 mM HEPES (pH 7.5) at 37°C.</p><p>Steady-state kinetic parameters of <i>C. glutamicum</i> Mca mutants for amidase activity of mycothiol bimane (MSmB).</p

Sensitivity of <i>C</i>. <i>glutamicum</i> strains to alkylating agents tested by disk diffusion assay.

<p>mBBr, monobromobimane; IAM, iodoacetamide; NEM, <i>N</i>-ethylmaleimide; CDNB, 1-chloro-2,4-dinitrobenzene MG, methylglyoxal. *<i>P</i>≤0.05 or **<i>P</i>≤0.01 versus wild type for the mutants.</p>a<p>The values are mean±SD for three independent determinations.</p><p>Sensitivity of <i>C</i>. <i>glutamicum</i> strains to alkylating agents tested by disk diffusion assay.</p