Fenofibrate modified-release pellets with lag phase and high oral bioavailability.

PURPOSE: Fenofibrate and statin combination therapy is highly recommended by the current clinical guidelines for treatment of mixed dyslipidemia. In this study, an innovative delayed-release preparation of fenofibrate was designed to reduce the risk of muscle toxicity, caused by simultaneous administration of this combination therapy, by altering the pharmacokinetic profile of fenofibrate, as well as to improve the oral bioavailability of the modified-release formulation. METHODS: Micronized fenofibrate was used to prepare drug-loaded cores via a powder layering process before multiparticulate pellet coating. Different coating formulations (Eudragit® RS PO/E100, Eudragit® RS PO/RL PO, Eudragit® NE30D/HPMC, and EC/HPMC) were screened, and their in vitro release was compared with the commercial sustained-release pellets Lipilfen®. Two optimized formulations were evaluated in beagle dogs using two commercial preparations of fenofibrate (the immediate-release preparation Lipanthyl® and the sustained-release pellets Lipilfen®) as references. RESULTS: The in vivo release of fenofibrate from R1 and R2 selected from in vitro tests exhibited a lag phase, and then rapid and complete drug release. The relative bioavailabilities of R1 and R2 were 100.4% and 201.1%, respectively, which were higher than that of Lipilfen® (67.2%). CONCLUSION: The modified fenofibrate pellets developed showed enhanced bioavailability and delayed-release properties. They have the potential to improve safety and compliance when co-administrated with statins. This is the first report of a delayed-release fenofibrate preparation.

In vitro and in vivo evaluation of a once-weekly formulation of an antidiabetic peptide drug exenatide in an injectable thermogel.

An injectable thermogel composed of poly(lactic acid-co-glycolic acid)-poly(ethylene glycol)-poly(lactic acid-co-glycolic acid) (PLGA-PEG-PLGA) triblock copolymers was evaluated as the matrix of a long-acting drug delivery system of exenatide (EXT), an antidiabetic peptide. The optimal gel formulation containing 2 mg/mL EXT and three pharmaceutical excipients (1.25 wt % zinc acetate, 5 wt % PEG200, and 5 wt % sucrose) was injected subcutaneously, and its pharmacokinetics was investigated. Both in vitro and in vivo release profiles exhibited a sustained release of EXT over 1 week. After a subcutaneous injection of the EXT formulation into db/db mice, the blood glucose level was maintained in a normal range up to 7 days and meanwhile the growth of body weight was suppressed. The in vivo results were consistent with the in vitro EXT-release profile. Moreover, twice injections of the gel formulation resulted in the higher blood insulin level and lower plasma concentration of glycosylated hemoglobin compared with twice-daily injections of an EXT solution for 18 days. Histological observations manifested the protection of islet due to administration of the gel formulation. Therefore, the PLGA-PEG-PLGA thermogel provided an excellent candidate for a once-weekly delivery system of EXT, and the optimal EXT formulation not only afforded therapeutic efficacy but also improved patient compliance.

Synergic effects of levamlodipine and bisoprolol on blood pressure reduction and organ protection in spontaneously hypertensive rats.

AIMS: Stroke is a major cause of disability and death worldwide. Hypertension is one of the most important risk factors for stroke. The objective of this work was to study the synergic effects of levamlodipine and bisoprolol on blood pressure reduction and organ protection in spontaneously hypertensive rats (SHR). METHODS: Blood pressure was continuously monitored in conscious SHR. For acute study, a single dose of drugs was administrated via an intragastric catheter. For chronic study (4 months), drugs were delivered via rat chow. RESULTS: A single dose of levamlodipine (from 1 mg/kg), bisoprolol (from 0.125 mg/kg), and their combinations significantly decreased blood pressure. The levamlodipine-induced tachycardia and the bisoprolol-induced bradycardia were temporized by the combination of these two drugs. Upon chronic treatment, this combination also decreased blood pressure variability and reduced organ damage. CONCLUSION: Levamlodipine and bisoprolol produce synergic effects on blood pressure reduction and organ protection in SHR.