Liver-targeted delivery of asiatic acid nanostructured lipid carrier for the treatment of liver fibrosis.

Liver fibrosis is a major global health concern. Management of chronic liver disease is severely restricted in clinics due to ineffective treatment approaches. However, a lack of targeted therapy may aggravate this condition. Asiatic acid (AA), a pentacyclic triterpenoid acid, can effectively protect the liver from hepatic disorders. However, the pharmaceutical application of AA is limited by low oral bioavailability and poor targeting efficiency. This study synthesized a novel liver-targeting material from PEG-SA, chemically linked to ursodeoxycholic acid (UA), and utilized it to modify AA nanostructured lipid carriers (UP-AA-NLC) with enhanced targeting and improved efficacy. The formulation of UP-AA-NLC was optimized via the Box-Behnken Experimental Design (BBD) and characterized by size, zeta potential, TEM, DSC, and XRD. Furthermore, in vitro antifibrotic activity and proliferation of AA and NLCs were assessed in LX-2 cells. The addition of UP-AA-NLC significantly stimulated the TGF-beta1-induced expression of α-SMA, FN1, and Col I α1. In vivo near-infrared fluorescence imaging and distribution trials in rats demonstrated that UP-AA-NLC could significantly improve oral absorption and liver-targeting efficiency. Oral UP-AA-NLC greatly alleviated carbon tetrachloride-induced liver injury and fibrosis in rats in a dosage-dependent manner, as reflected by serum biochemical parameters (AST, ALT, and ALB), histopathological features (H&E and Masson staining), and antioxidant activity parameters (SOD and MDA). Also, treatment with UP-AA-NLC lowered liver hydroxyproline levels, demonstrating a reduction of collagen accumulation in the fibrotic liver. Collectively, optimized UP-AA-NLC has potential application prospects in liver-targeted therapy and holds great promise as a drug delivery system for treating liver diseases.

pH-sensitive chitosan-deoxycholic acid/alginate nanoparticles for oral insulin delivery.

Oral absorption of peptides/proteins is usually compromised by various gastrointestinal tract barriers. To improve delivery efficiency, chitosan-conjugated deoxycholic acid (CS-DCA) coupled with sodium alginate (ALG) was prepared to load insulin into pH-sensitive nanoparticles. The insulin-loaded chitosan-deoxycholic acid/alginate nanoparticles (CDA NPs) were characterized by size (143.3 ± 10.8 nm), zeta potential (19.5 ± 1.6 mV), entrapment efficiency (61.14 ± 1.67%), and insulin drug loading (3.36 ± 0.09%). The CDA NPs exhibited pH-triggered release characteristics in vitro and protected the wrapped insulin from gastric degradation. Stability of the CDA NPs in enzyme-containing simulated gastrointestinal fluids suggested that the NPs could partially protect the wrapped insulin from enzymatic degradation. Additionally, CS-DCA-modified NPs promoted the permeability of Caco-2 cells and enhanced intracellular absorption of FITC-labeled insulin by 9.4 and 1.2-folds, when compared to insulin solution and unmodified NPs, respectively. The positively charged NPs increased intestinal villi adhesion and enhanced insulin absorption in the intestines of diabetic rat models. Furthermore, the hypoglycemic test showed that CDA NPs prolonged insulin release in vivo and exerted a remarkable hypoglycemic effect on diabetic rats with an oral bioavailability of 15%. In conclusion, CDA NPs is a potential oral insulin delivery system.

Stereoselectivity evaluation of chiral chitosan microspheres delivery system containing rac-KET in vitro and in vivo.

The influence of chiral excipient D-chitosan (CS) on the stereoselective release of racemic ketoprofen (rac-KET) microspheres has been investigated in comparison to those microspheres containing individual enantiomers in vitro and in vivo. Stereoselectivity was observed in vitro release test, with R-KET release slightly higher than that of S-KET, especially in 3% rac-KET loading microspheres. Stereoselectivity is dependent on the content of chiral excipient and pH of release medium. A molecular docking study between CS and KET enantiomers further revealed that S-KET has a stronger interaction with CS compared to R-KET. Moreover, the plasma concentration of KET enantiomers in rats shows substantial differences, as the plasma levels of S-KET were higher than those of R-KET. Plasma levels of enantiomers from the R-KET microspheres had similar stereoselectivity as rac-KET microspheres. The S/R ratio of rac-KET microspheres was significantly lower than that of rac-KET suspension (regular-release formulation) (p<.05), and the differences is 3-5 fold. Besides, rates of R-KET converted to S-KET exhibited differences between rac-KET microspheres and suspension. Similar results were also found between R-KET microspheres and suspension. All investigations suggest that the chitosan interacting preferentially with S-KET to R-KET significantly affect the stereoselective pharmacokinetics of rac-KET from chitosan microspheres in rats.

[Experimental study on therapeutic effect of Dabuyin Wan on true precocious puberty in female rats].

OBJECTIVE: To study the therapeutic effect of Dabuyin Wan on true precocious puberty of female rats and its possible mechanism. METHOD: Twenty-two-day-old female SD rats were subcutaneously injected with 40 mg x kg(-1) N-methyl-DL-aspartic acid (NMA) at 14:00 and 16:00 every day; meanwhile, the rats were given Dabuyin Wan for intervention. Visual inspection was conducted for the time of vaginal opening. The first estrus was observed by yaginal smear test. Their ovaries and uterus were weighed to calculate organ coefficients. Conventional pathological slices were made to observe morphological changes in ovaries and uterus and calculate the thickness of uterine walls and the number of corpus luteums. The level of E2 in serum was detected to assess the therapeutic effect of Dabuyin Wan on NMA precocious puberty in rats. expressions of GnRH, GPR54 and Kiss-1 mRNA in hypothalamus were measured by semi-quantitative RT-PCR to investigate the possible mechanism of Dabuyin Wan. RESULT: Dabuyin Wan at 3.24 g x kg(-1) and 1.62 g x kg(-1) significantly decreased the organ coefficients in rats with precocious puberty (P < 0.05), decrease the number of vaginal openings in rats (P < 0.01) and the thickness of uterine walls and the number of corpus luteums (P < 0.05), and notably down-regulated expressions of GnRH, GPR54 and Kiss-1 mRNA in hypothalamus (P < 0.05), without significant impact on E2 in serum. CONCLUSION: Dabuyin Wan may inhibit GnRH synthesis and release as well as startup of hypothalamic-pituitary-gonadal axis by down-regulating Kiss-1/GPR54 mRNA expression in hypothalamus, in order to realize the therapeutic effect on true precocious puberty.

[Changes of element contents and their interrelationship in tibia of osteoporotic rats]

OBJECTIVE: To observe the changes of bone element contents in osteoporosis and their interrelationship. METHODS: Twelve female SD rats,10-month-old, were bilaterally ovariectomized (OVX group) and another ten rats were received sham-operation under anesthesia (SHAM group).The element contents in tibia, including Ca, P, Mg, Zn, Mn, Fe, Cu, Mo and Cr, were determined by atomic absorption spectrophotometer 7 month later. The data of contents of all elements were analyzed by simple regression. RESULTS: Compared with the SHAM group rats, the contents of Ca, P and Mg were decreased by 6.6 %(P<0.05), 6.3 %(P<0.05) and 14.9 %(P<0.01) respectively. The contents of Zn and Fe were reduced by 15.2 %(P<0.01) and 35.1 %(P<0.01) separately, Mo and Cr were decreased by 12.2 %(P>0.05) and 14.0 %(P>0.05), while the contents of Mn, Cu and Co were shown no change. There was a significant correlation among the contents of Mg, Mn, Zn, Ca and P. CONCLUSION: The contents of Ca, P, Mg, Zn and Fe were matkedly reduced in bone of osteoporotic rats induced by ovariectomy.