Preparation and evaluation of HPMC-based pirfenidone solution in vivo.

CONTEXT: Pirfenidone (PFD) has exhibited therapeutic potential in the treatment of cell proliferative disorders. The previously developed 0.5% water-based PFD eye drops by our team exhibited antiscarring effectiveness and ocular safety but with a limit of short half-life and poor bioavailability. OBJECTIVE: To increase bioavailability of the water-based PFD eye drops, we prepared a viscous solution by adding hydroxypropyl methylcellulose (HPMC, F4M), which acted as a viscosity-enhancer. Subsequently, we compared the HPMC-based PFD solution with the water-based PFD eye drops. MATERIALS AND METHODS: PFD solution with 1% HPMC (w/v) was prepared, and the viscosities at different shear rates were measured to investigate its rheology. PFD concentrations in the tear, aqueous humor, conjunctiva, cornea, and sclerae of New Zealand rabbits were detected at different time points with high-performance liquid chromatography (HPLC) following single instillation of the 0.5% PFD (w/v) water-based eye drops or HPMC-based solution. RESULTS: Compared with the 0.5% water-based PFD eye drops, the HPMC-based solution increased the PFD levels in tears and prolonged the residence time from 10 to more than 20 min (p < .01). Consequently, the concentrations of PFD in aqueous humor, conjunctiva, cornea, and sclera were elevated to varying degrees until 90 min after topical administration. CONCLUSIONS: The developed formulation possesses a same readily administration and simple preparation as the PFD eye drops; however, the HPMC-based solution exhibited the higher bioavailability.

[Advances in the quantitative analytical methods of drug polymorphism].

Polymorphism of drug is known to influence the stability, dissolution, bioavailability and other performance characteristics of the products. Therefore, the crystal form of the drug must be identified and determined in order to ensure consistent product performance. Even if the identification and characterization of crystal forms are performed thoroughly and the effective crystal form is selected for preparation, it is important to ensure that the effective crystal form in the final product remains unchanged. Therefore, it is essential to quantitate the content of the effective crystal form in the product to control the quality and performance of them. X-ray powder diffraction, FT-Raman, mid-IR, near-IR, terahertz pulsed spectroscopy, solid-state NMR spectroscopy, and DSC are the quantitative methods of crystal form used in the recent 10 years. This review briefly highlights the basic principles and the progress of these methods and discusses the perspective as they apply to pharmaceutical research and development.

[Preparation of in situ gel systems for the oral delivery of ibuprofen and its pharmacokinetics study in beagle dogs].

The in situ gel systems can form gel in situ after administration to achieve sustained release, thus provides a promising strategy for drug delivery systems. The aim of this study was to design and prepare in situ gel systems for the oral delivery of ibuprofen (IBU-ISG) and study its pharmacokinetics in Beagle dogs. The characteristics of the basic material of gellan gum (Kelcogel, Kel) and sodium alginate (Manugel, M) were studied through investigating the complex viscosity of the Kel or M solution with or without different concentrations of calcium ion or sodium citrate to ascertain the amount range of the excipients. The measurement of complex viscosity of the solution (0. 5% Kel and 1% M) with different concentrations of sodium citrate and calcium ion was carried out to select the suitable proportion of calcium ion and sodium citrate. The formulation of binary IBU-ISG was optimized by monitoring the complex viscosity before gelling in vitro release property. The optimized formulation contains 1.0% sodium alginate, 0.5% gellan gum, 0. 21% sodium citrate and 0.056% calcium chloride. A single oral dose of IBU-ISG and reference formulation (IBU suspension) were given to each of the 6 healthy Beagle dogs, ibuprofen in plasma at different sampling times was determined by RP-HPLC. The pharmacokinetics parameters in 6 Beagle dogs were calculated. The Tmax of IBU-ISG and reference formulation were (1.8 +/- 0.6) and (0.4 +/- 0. 1) h. The Cmax values were (29.2 +/- 7.6) and (37.8 +/- 2.2) microg x mL(-1). The T(1/2) were (2.3 +/- 0.5) and (2.0 +/- 0.9) h, and the AUC(0-t) were (131.0 +/- 38.6) and (117.3 +/- 23.1) microg x mL(-1) x h, respectively. The binary IBU-ISG was successfully prepared.

[Assessment of Pueraria lobata isoflavone with self-microemulsifying drug delivery systems in vitro and in vivo].

OBJECTIVE: To evaluate the self-microemulsifying ability and dissolution behavior of pueraria lobata isoflavone in vitro and the pharmacokinetic behavior in rats. METHODS: The self-microemulsifying rate was evaluated by the self-microemulsifying time and the self-microemulsifying efficiency was evaluated by the particle size of resultant microemulsions. The plasma concentrations were evaluated by HPLC and dissolution and pharmacokinetic behavior of self-microemulsifying drug delivery systems were evaluated by comparison with commercial tablets. RESULTS: The system was self-microemulsified in 2 min and the particle size was less than 50 nm. The dis- solution of SMESC in distilled water was more than 90% at 10 min, while those of the commercial tablet were less than 50% at 120 min. 82% increase in the relative bioavailability was observed for the self microemulsifying drug delivery systems compared with Yufengningxin tablets. Tmax was smaller in the self-microemulsifying drug delivery systems compared with Yufengningxin tablets. CONCLUSION: The self-microemulsifying drug delivery systems can increase drug dissolution in vitro and absorption in vivo significantly.