Mirabegron (MBR) is a β₃-adrenoceptor agonist used for treating overactive bladder syndrome. Due to its poor solubility and low bioavailability (F), the development of novel MBR formulations has garnered increasing attention. Recently, co-amorphous dispersions of MBR, such as MBR-1,2-ethanedisulfonic acid (MBR-EFA), MBR-1,5-naphthalenedisulfonic acid (MBR-NDA), and MBR-L-pyroglutamic acid (MBR-PG), have been developed, showing improved solubility and thermodynamic stability. Nevertheless, the pharmacokinetic feasibility of these co-amorphous dispersions has not been evaluated. Therefore, this study aimed to characterize the pharmacokinetic profiles of MBR-EFA, MBR-NDA, and MBR-PG in rats and mice. Our results exhibited that relative F_24h and AUC_0–24h values of MBR in MBR-EFA, MBR-NDA, and MBR-PG rats were increased by 143–195% compared with the MBR rats. The absolute F_24h, relative F_24h, and AUC_0–24h values of MBR in MBR-EFA and MBR-NDA mice were enhanced by 178–234% compared with the MBR mice. In tissue distribution, MBR was extensively distributed in the gastrointestinal tract, liver, kidneys, lung, and heart of mice. Notably, MBR distribution in the liver, kidneys, and lung was considerably high in MBR-EFA, MBR-NDA, or MBR-PG mice compared with MBR mice. These findings highlight the potential of these co-amorphous dispersions to enhance oral F of MBR.

Febuxostat (FBX), a selective xanthine oxidase inhibitor, belongs to BCS class II, showing low solubility and high permeability with a moderate F value (<49%). Recently, FBX/L-pyroglutamic acid cocrystal (FBX-PG) was developed with an improving 4-fold increase of FBX solubility. Nevertheless, the in vivo pharmacokinetic properties of FBX-PG have not been evaluated yet. Therefore, the pharmacokinetic feasibility of FBX in FBX- and FBX-PG-treated rats and mice was compared in this study. The results showed that the bioavailability (F) values of FBX were 210% and 159% in FBX-PG-treated rats and mice, respectively. The 2.10-fold greater total area under the plasma concentration–time curve from time zero to infinity (AUC_0-inf) of FBX was due to the increased absorption [i.e., 2.60-fold higher the first peak plasma concentration (C_max,1) at 15 min] and entero-hepatic circulation of FBX [i.e., 1.68-fold higher the second peak plasma concentration (C_max,2) at 600 min] in FBX-PG-treated rats compared to the FBX-treated rats. The 1.59-fold greater AUC_0-inf of FBX was due to a 1.65-fold higher C_max,1 at 5 min, and a 1.15-fold higher C_max,2 at 720 min of FBX in FBX-PG-treated mice compared to those in FBX-treated mice. FBX was highly distributed in the liver, stomach, small intestine, and lungs in both groups of mice, and the FBX distributions to the liver and lungs were increased in FBX-PG-treated mice compared to FBX-treated mice. The results suggest the FBX-PG has a suitable pharmacokinetic profile of FBX for improving its oral F value.

Tenofovir (TEV) is a nucleotide reverse transcriptase inhibitor used against human immunodeficiency virus (HIV) reverse transcriptase. To improve the poor bioavailability of TEV, TEV disoproxil (TD), an ester prodrug of TEV, was developed, and TD fumarate (TDF; Viread^®) has been marketed due to the hydrolysis of TD in moisture. Recently, a stability-enhanced solid-state TD free base crystal (SESS-TD crystal) was developed with improved solubility (192% of TEV) under gastrointestinal pH condition and stability under accelerated conditions (40 °C, RH 75%) for 30 days. However, its pharmacokinetic property has not been evaluated yet. Therefore, this study aimed to evaluate the pharmacokinetic feasibility of SESS-TD crystal and to determine whether the pharmacokinetic profile of TEV remained unchanged when administering SESS-TD crystal stored for 12 months. In our results, the F and systemic exposure (i.e., AUC and C_max) of TEV in the SESS-TD crystal and TDF groups were increased compared to those in the TEV group. The pharmacokinetic profiles of TEV between the SESS-TD and TDF groups were comparable. Moreover, the pharmacokinetic profiles of TEV remained unchanged even after the administration of the SESS-TD crystal and TDF stored for 12 months. Based on the improved F after the SESS-TD crystal administration and the stable condition of the SESS-TD crystal after 12 months, SESS-TD crystal may have enough pharmacokinetic feasibility to replace TDF.

The suppressive effects of flavonoids on macrophage-associated adipocyte inflammation in a differentiated murine preadipocyte cell line (3T3-L1) co-cultured with a murine macrophage cell line (RAW264.7) were evaluated. Extracellular lipid accumulation was investigated via Oil Red O staining. The expression levels of adipogenesis- and inflammation-associated proteins, including CCAAT/enhancer-binding protein (C/EBP)-α, inducible nitric oxide synthase (iNOS), C/EBPβ, peroxisome proliferator-activated receptor γ (PPARγ), and cyclooxygenase-2 (COX-2), were determined via Western blotting. Proinflammatory cytokines, including monocyte chemoattractant protein 1 (MCP-1) and interleukin-6 (IL-6), were assessed using enzyme-linked immunosorbent assay kits. We found that silybin, formononetin, and diosmetin inhibited lipid accumulation and production of proinflammatory cytokines in the co-cultures of 3T3-L1 and RAW264.7 cells. Moreover, they inhibited the protein expression of PPARγ, C/EBPα, COX-2, C/EBPβ, and iNOS in the co-cultures of 3T3-L1 and RAW264.7 cells. These data support that silybin, formononetin, and diosmetin inhibit macrophage-associated adipocyte inflammation and lipid accumulation.

Febuxostat (FBX), a selective xanthine oxidase inhibitor, belongs to BCS class II showing low solubility and high permeability with a moderate F value (< 49%). Recently, FBX/L-pyroglutamic acid cocrystal (FBX-PG) was developed with improving 4-fold increase of the FBX solubility. Nevertheless, in vivo pharmacokinetic property of FBX-PG has not been evaluated yet. Therefore, the pharmacokinetic feasibility of FBX in FBX and FBX-PG-treated rats and mice was compared in this study. The results showed that the F values of FBX were 210% and 159% in FBX-PG rats and mice, respectively. The 2.10-fold greater AUC of FBX was due to the increased absorption (i.e., 2.60-fold higher Cmax,1 at 15 min) and entero-hepatic circulation of FBX (i.e., 1.68-fold higher Cmax,2 at 600 min) in FBX-PG rats compared to the FBX rats. The 1.59-fold greater AUC of FBX was due to a 1.65-fold higher Cmax,1 at 5 min, and 1.15-fold higher Cmax,2 at 720 min of FBX in FBX-PG mice than those in FBX mice. FBX was highly distributed in the liver, stomach, small intestine, and lungs in both groups of mice, and the FBX distributions to the liver and lungs were increased in FBX-PG mice compared to FBX mice. The results suggest the FBX-PG has a suitable pharmacokinetic profile of FBX for improving its oral F value.