Biomedical subjects

Libo Yang

Publications and source records attributed to Libo Yang.

5 recordsLinked to original sources

PubMed2005

[Effect of shensong yangxin capsule on ventricular premature beat and cardiovascular autonomic nervous function in patients with coronary heart disease].

OBJECTIVE: To observe the clinical efficacy of shensong yangxin capsule (SYC) on ventricular premature beat (VPB) differentiated in TCM as palpitation of Qi-yin deficiency syndrome or Xin collateral stagnation syndrome, and cardiovascular autonomic nervous function in patients with coronary heart disease (CHD). METHODS: The randomized, double-blind, parallel contrast method was adopted, patients were randomly assigned by 3:1 ratio into two groups. One hundred and sixty-five patients in SYC treated group and 56 in the control group (treated with Xinlvning tablet), and the therapeutic course for both groups was 4 weeks. RESULTS: The clinical efficacy on VPB and in improving TCM syndromes was better in SYC group than that in the control group (P < 0.01). After treatment, the heart rate variability (HRV) and QT dispersion in the two groups were improved in a certain degree. The changes of SDNN, SDANN, SDNN Index and PNN50 in the two groups were significantly different (P < 0.05, P < 0.01), the efficacy in the treated group was superior to that in the control group. CONCLUSION: SYC has definite effect on VPB and TCM Syndromes, it can obviously meliorate the activity of cardiovascular autonomic nervous system in the patients with CHD.

Adult↗

PubMed2003

Effect of colonic lactulose availability on the timing of drug release onset in vivo from a unique colon-specific drug delivery system (CODES).

PURPOSE: To test the hypothesis that the onset of drug release in vivo from a unique colon-specific drug delivery system (CODES) would depend on the colonic availability rate of lactulose. The site specificity of drug release in canine GI tract was also estimated. METHODS: CODES tablets were prepared by tableting the granulation or acetaminophen and lactulose, followed with film coating. The pharmacokinetic performance of different CODES formulations was evaluated in six beagle dogs under fasted conditions. The release of acetaminophen and lactulose was also characterized in vitro. RESULTS: The onset of acetaminophen release in beagle dogs was found to be dependent on the coating level of Eudragit E and lactulose loading in the core tablet. At Eudragit E coating levels of 4%, 8% and 12% (coating weight gain), the onset of in vivo drug release occurred 5.5 (+/- 1.9) h. 4.8 (+/-1.0) h. and 7.5 (+/-1.0) h, respectively, after dosing. A similar trend was observed when the loading of lactulose in the core tablet decreased from 78% to 58% and 38%. However, the rate and extent of acetaminophen absorption did not vary significantly in each situation based on the values of AUC and Cmax. CONCLUSION: The onset of drug release in vivo from CODES tablets is predominantly dependent on colonic availability rate of lactulose because drug release from this system is triggered by localized drop of colonic pH from the fermentation of lactulose.

Acetaminophen↗

PubMed2003

Accessibility of solid core tablet for dissolution in an asymmetric triple-layer matrix system.

The importance of glassy matrix surface area to ensure constant drug release and the effect of barrier layer thickness on the duration of linear release in an asymmetric triple-layer tablet with zero-order release kinetics were investigated. Poly(ethylene oxide) of different molecular weights and hydroxypropylmethylcellulose K4M were the major polymeric constituents, and verapamil hydrochloride was used as a drug model. The contribution of diffusion and polymer relaxation towards drug release was evaluated based on drug release data using a non-linear regression analysis algorithm. The results demonstrated that application of barrier layers to the central core tablet enables polymer relaxation to be the predominant mechanism in controlling drug release and leads to the often desired zero-order release kinetics. The duration of linear release from the asymmetric triple-layer tablet depends on the barrier layer thickness and composition. It was further indicated that the magnitude of diffusion and polymer relaxation in controlling drug release is affected by the accessibility of the drug core tablet for dissolution, as well as the inherent swelling and erosion characteristics of the release rate-controlling polymer.

Administration, Oral↗

PubMed2002

Colon-specific drug delivery: new approaches and in vitro/in vivo evaluation.

The necessity and advantages of colon-specific drug delivery systems have been well recognized and documented. In the past, the primary approaches to obtain colon-specific delivery achieved limited success and included prodrugs, pH- and time-dependent systems, and microflora-activated systems. Precise colon drug delivery requires that the triggering mechanism in the delivery system only respond to the physiological conditions particular to the colon. Hence, continuous efforts have been focused on designing colon-specific delivery systems with improved site specificity and versatile drug release kinetics to accommodate different therapeutic needs. Among the systems developed most recently for colon-specific delivery, four systems were unique in terms of achieving in vivo site specificity, design rationale, and feasibility of the manufacturing process (pressure-controlled colon delivery capsules (PCDCs), CODES, colonic drug delivery system based on pectin and galactomannan coating, and Azo hydrogels). The focus of this review is to provide detailed descriptions of the four systems, in particular, and in vitro/in vivo evaluation of colon-specific drug delivery systems, in general.

Animals↗

PubMed2002

In vitro evaluation of dissolution behavior for a colon-specific drug delivery system (CODES) in multi-pH media using United States Pharmacopeia apparatus II and III.

United States Pharmacopeia dissolution apparatus II (paddle) and III (reciprocating cylinder) coupled with automatic sampling devices and software were used to develop a testing procedure for acquiring release profiles of colon-specific drug delivery system (CODES) drug formulations in multi-pH media using acetaminophen (APAP) as a model drug. System suitability was examined. Several important instrument parameters and formulation variables were evaluated. Release profiles in artificial gastric fluid (pH 1.2), intestinal fluid (pH 6.8), and pH 5.0 buffer were determined. As expected, the percent release of APAP from coated core tablets was highly pH dependent. A release profile exhibiting a negligible release in pH 1.2 and 6.8 buffers followed by a rapid release in pH 5.0 buffer was established. The drug release in pH 5.0 buffer increased significantly with the increase in the dip or paddle speed but was inversely related to the screen mesh observed at lower dip speeds. It was interesting to note that there was a close similarity (f2 = 80.6) between the release profiles at dip speed 5 dpm and paddle speed 100 rpm. In addition, the release rate was reduced significantly with the increase in acid-soluble Eudragit E coating levels, but lactulose loading showed only a negligible effect. In conclusion, the established reciprocating cylinder method at lower agitation rates can give release profiles equivalent to those for the paddle procedure for CODES drug pH-gradient release testing. Apparatus III was demonstrated to be more convenient and efficient than apparatus II by providing various programmable options in sampling times, agitation rates, and medium changes, which suggested that the apparatus III approach has better potential for in vitro evaluation of colon-specific drug delivery systems.

Acetaminophen↗