Advances in Pharmaceutical Strategies Enhancing the Efficiencies of Oral Colon-Targeted Delivery Systems in Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) is a common disease characterized by chronic inflammation in gastrointestinal tracts, which is primarily treated by administering anti-inflammatory and immunosuppressive drugs that inhibit the burden of intestinal inflammation and improve disease-related symptoms. However, the established therapeutic strategy has limited therapeutic efficacy and adverse drug reactions. Therefore, new disease-targeting drug-delivery strategies to develop more effective treatments are urgent. This review provides an overview of the drug-targeting strategies that can be used to treat IBD, and our recent attempts on the colon-specific delivery system (Pae-SME-CSC) with a paeonol-loaded self-microemulsion (Pae-SMEDDS) are introduced.

Beneficial anti-inflammatory effect of paeonol self-microemulsion-loaded colon-specific capsules on experimental ulcerative colitis rats.

Paeonol, as the main phenolic compound isolated from the Chinese herbs, has been confirmed to present anti-inflammatory effects on ulcerative colitis (UC) in our previous study. However, its poor solubility has hindered its development of being a favourable pharmaceutical product in treating colon diseases. In this study, we prepared the colon-specific delivery system (Pae-SME-CSC) with paeonol-loaded self-microemulsion (Pae-SMEDDS), and evaluated its in vitro and in vivo properties, especially the anti-inflammatory effects on UC rats. The anti-inflammatory effects were evaluated by the disease activity index, colon weight/length ratio, and macroscopic damage and microscopic damage scores. IL-17, IL-6, and TGF-ß1 levels were also determined by enzyme-linked immunosorbent assay. The results showed that Pae-SME-CSC had good colon-targeting property in vivo and in vitro, with favourable stability. Efficacy evaluation showed that the dose of the paeonol group (100 mg/kg) exhibited no significant effect on UC (p > .05, compared with the model group), while the Pae-SME-CSC group (100 mg/kg) showed better anti-UC effects (p < .01 or p < .05), and its anti-inflammatory effect was close to that of the paeonol group (200 mg/kg) (p > .05). These results indicated that the developed Pae-SME-CSC was suitable for colon-specific drug delivery.

Formulation Optimization of Gastro-Retention Tablets of Paeonol and Efficacy in Treatment of Experimental Gastric Ulcer.

This study aims to develop a gastroretentive sustained-release drug delivery system of paeonol using floating properties and to investigate its therapeutic effects in rat models. The gastric retention tablets of paeonol (GRT-Ps) were prepared by a direct compression method, and the Box-Behnken design was used to optimize its formulation. The optimized formulation containing 15% NaHCO3 and a 2 : 1 ratio of paeonol and HPMC-K4M floated within 1 min and remained afloat for more than 8 h in the simulated gastric fluid (200 mL, pH=1.2) and simultaneously showed the desired sustained drug release. Moreover, small tablets (3 mm) were prepared according to the same formulation and the process technology of big tablets (8 mm). A similar drug release behavior was observed between two kinds of tablets (f2=52), and then the evaluations of efficacy and retention capacity in vivo were conducted with small tablets. In vivo retention studies showed that the Tmax (2 h) of GRT-P in rat stomachs was significantly extended compared with the Tmax (0.5 h) of normal reference preparation. Compared with the model group, low and high doses of GRT-P could significantly inhibit the increase of malondialdehyde (MDA) in serum. Studies showed that the higher MDA content in inflammation tissue increases the inflammatory response. The ulcer inhibition rates of GRT-P in the high-dose group were 59.0 and 64.1% in the ranitidine group. Results indicated that GRT-Ps had the potential for a sustained drug release and an enhanced gastric residence time with relatively high drug concentrations in the tissue distribution.

Study on the physicochemical properties and anti-inflammatory effects of paeonol in rats with TNBS-induced ulcerative colitis.

Paeonol, an active component from Paeonia suffruticosa Andr., has a variety of biological activities, such as vascular endothelial cell protection, anti-oxidation, and anti-inflammation. The aim of this study was to investigate the basic physicochemical properties of paeonol, including solubility, oil-water partition coefficient, and permeability. Then evaluated the anti-inflammatory effects of paeonol were evaluated on 2,4,6-trinitrobenzenesulfonic acid-induced ulcerative colitis in rats. The rats were divided randomly into 6 groups, namely, normal, model, paeonol-treated (100, 200, and 400mg/kg), and positive. Each group had 10 rats. Inhibition effects were evaluated by the disease activity index (DAI), colon weight/length ratio, as well as macroscopical and histological evaluations. Serum interleukin (IL)-17, IL-6 and transforming growth factor beta 1 (TGF-ß1) levels were determined by enzyme-linked immunosorbent assay. The solubility and oil-water partition coefficient of paeonol in different phosphate buffer solutions were 284.06-598.23 and 461.97-981.17µg/mL, respectively. The effective passive permeability value Pe was 23.49×10-6cm/s. In terms of anti-inflammatory results, compared with the model group, treatment with 200 and 400mg/kg doses of paeonol had significantly decreased DAI, colon weight/length ratio, and macroscopic and histopathological scores. Furthermore, the serum levels of IL-17 and IL-6 were significantly reduced, whereas the TGF-ß1 level was increased in the two paeonol-treated groups (medium- and high-dose group). Therefore, paeonol had poor water solubility, but oral absorption was good. In addition, paeonol had therapeutic effects on ulcerative colitis, and the therapeutic efficacy was dose dependent. The results presented in this study provide evidence for the development of a novel therapeutic agent in the treatment of UC. However, whether this agent could have therapeutic benefit or adverse effects in human IBD remains to be fully explored.

Self-microemulsifying Drug Delivery System Improved Oral Bioavailability of 20(S)-Protopanaxadiol: From Preparation to Evaluation.

20(S)-Protopanaxadiol (20(S)-PPD) is one type of sapogenin of protopanaxadiols and has a variety of pharmacological activities. In order to improve the dissolution of 20(S)-PPD as well as its oral bioavailability, a self-microemulsifying drug delivery system (SMEDDS) was utilized for 20(S)-PPD preparation. Following the preparation of the 20(S)-PPD SMEDDS, its dissolution, stability, and intestinal absorption in rats were studied, and the pharmacokinetics and optimal dosage after oral administration were evaluated. The dissolution tendency of the SMEDDS in phosphate buffered saline (PBS), 0.1 M HCl and distilled water was consistent. SMEDDS was stable under a condition of high temperature (40°C), high humidity or with strong light irradiation, or within 6 h in artificial digestive tracts. 20(S)-PPD SMEDDS was well-absorbed in all intestinal segments in rats. When the drug concentration was higher than 200 µg/mL or the perfusion flow was faster than 0.5 mL/min, passive diffusion of drug in the duodenum reached a saturated level. In addition, P-glycoprotein inhibitor did not affect the intestinal absorption of 20(S)-PPD SMEDDS. Pharmacokinetic study showed that Tmax in male rats was shortened significantly, while Cmax and area under the curve (AUC(0-t)) were remarkably increased. The relative oral bioavailability of 20(S)-PPD SMEDDS was increased approximately three fold compared with the 20(S)-PPD carboxy methyl cellulose (CMC). 20(S)-PPD SMEDDS (100 mg/mL) was administered by gastric infusion to both mice and rats for 14 d. SMEDDS improved the oral bioavailability of 20(S)-PPD and reduced the necessary drug dosage. 20(S)-PPD SMEDDS could become a promising clinical alternative as an anti-tumor or antidepressant drug.

[Optimization of Ethanol Extraction and Water Extraction Technologies of Zuogui Pills by Orthogonal Test].

OBJECTIVE: To optimize the ethanol extraction and water extraction technologies of Luogui Pills. METHODS: An orthogonal test was used to study the influence of ethanol concentration, amount of ethanol and reflux time on hyperoside in Cuscutae Semen, ursolic acid in Corni Fructus and the yield of dry paste. Also, The effect of soaking time, amount of water and extraction time on acteoside in Rehmanniae Radix Praeparata and the yield of dry paste were investigated. All these factors were adopted as the indices for choosing the best ethanol extraction and water extraction technologies. RESULTS: The best ethanol extraction technology for Cuscutae Semen, Corni Fructus and Achyranthis Bidentatae Radix was reflux extracting for 1 h each time for two times with eight times of 70% ethanol. The best water extraction technology for the residue and the rest herbs after the ethanol extraction was soaking for 0. 5 h and then decocting for 0. 5 h each time for two times with twelve times of water. CONCLUSION: The optimal extraction technologies are stable and feasible, the extraction rate of the alcohol soluble and water soluble effective components is high, and it provides the reference basis for the secondary development of Zuogui Pills.