Enhanced dissolution, stability and physicochemical characterization of ATRA/2-hydroxypropyl-β-cyclodextrin inclusion complex pellets prepared by fluid-bed coating technique

Solid lipid nanoparticles with enteric coating for improving stability, palatability, and oral bioavailability of enrofloxacin

Background

The poor palatability, variable oral bioavailability, stimulation to gastric mucosa, and light instability limited the application of enrofloxacin (ENR). The enteric granules combining solid lipid nanoparticles (SLNs) with enteric coating were explored to overcome these disadvantages.

Materials and methods

ENR-loaded SLNs were produced by a hot homogenization and ultrasonic emulsification method and the enteric granules with SLNs as inner core were prepared by wet granulation followed by coating using polyacrylic resin II (PRII). The formulation was optimized by using orthogonal or single factor test screening.

Results

The optimal SLNs with loading capacity (LC) and price as inspection indexes were consisted of 10 mL 3% polyvinyl alcohol per 0.8 g ENR and 2.4 g octadecanoic acid. The sizes, LC, polydispersion index, and zeta potential of the SLNs were 308.5±6.3 nm, 15.73%±0.31%, 0.352±0.015, and −22.3 mv, respectively. The best enteric granules were used 15% PRII as coating materials. The release of the enteric granules in simulated intestine fluid (SIF, pH=8) was significantly faster than in simulated gastric fluid (SGF, pH=2) and simultaneously slower than those of SLNs and native ENR. The granules showed good stability in influencing factor experiment. The granules displayed a similar daily feed intake as the control group and higher daily feed intake than ENR powder and single-coating granules. Compared to the ENR soluble powder, the area under the plasma concentration–time curve and mean retention time of the enteric granules after intragastric administration were increased from 4.26±0.85 µg h/mL and 6.80±2.28 hours to 11.24±3.33 µg h/mL and 17.97±4.01 hours, respectively.

Conclusion

The enteric granules combination SLNs with enteric coating significantly improved the stability, palatability, sustained-release performance and oral bioavailability of ENR. The novel technology will be a potential measure to overcome the similar disadvantages of other drugs.

The role of lipid-based nano delivery systems on oral bioavailability enhancement of fenofibrate, a BCS II drug: comparison with fast-release formulations

The aim of this study was to compare various formulations solid dispersion pellets (SDP), nanostructured lipid carriers (NLCs) and a self-microemulsifying drug delivery system (SMEDDS) generally accepted to be the most efficient drug delivery systems for BCS II drugs using fenofibrate (FNB) as a model drug. The size and morphology of NLCs and SMEDDS was characterized by dynamic light scattering (DLS) and transmission electron microscopy (TEM). Their release behaviors were investigated in medium with or without pancreatic lipase. The oral bioavailability of the various formulations was compared in beagle dogs using commercial Lipanthyl® capsules (micronized formulation) as a reference. The release of FNB from SDP was much faster than that from NLCs and SMEDDS in medium without lipase, whereas the release rate from NLCs and SMEDDS was increased after adding pancreatic lipase into the release medium. However, NLCs and SMEDDS increased the bioavailability of FNB to 705.11% and 809.10%, respectively, in comparison with Lipanthyl® capsules, although the relative bioavailability of FNB was only 366.05% after administration of SDPs. Thus, lipid-based drug delivery systems (such as NLCs and SMEDDS) may have more advantages than immediate release systems (such as SDPs and Lipanthyl® capsules).

Bile salt/phospholipid mixed micelle precursor pellets prepared by fluid-bed coating

Bile salt/phospholipid mixed micelles (MMs) are potent carriers used for oral absorption of drugs that are poorly soluble in water; however, there are many limitations associated with liquid formulations. In the current study, the feasibility of preparing bile salt/phospholipid MM precursor (preMM) pellets with high oral bioavailability, using fluid-bed coating technology, was examined. In this study, fenofibrate (FB) and sodium deoxycholate (SDC) were used as the model drug and the bile salt, respectively. To prepare the MMs and to serve as the micellular carrier, a weight ratio of 4:6 was selected for the sodium deoxycholate/phospholipids based on the ternary phase diagram. Polyethylene glycol (PEG) 6000 was selected as the dispersion matrix for precipitation of the MMs onto pellets, since it can enhance the solubilizing ability of the MMs. Coating of the MMs onto the pellets using the fluid-bed coating technology was efficient and the pellets were spherical and intact. MMs could be easily reconstituted from preMM pellets in water. Although they existed in a crystalline state in the preMM pellets, FB could be encapsulated into the reconstituted MMs, and the MMs were redispersed better than solid dispersion pellets (FB:PEG = 1:3) and Lipanthyl®. The redispersibility of the preMM pellets increased with the increase of the FB/PEG/micellar carrier. PreMM pellets with a FB:PEG:micellar carrier ratio of 1:1.5:1.5 showed 284% and 145% bioavailability relative to Lipanthyl® and solid dispersion pellets (FB:PEG = 1:3), respectively. Fluid-bed coating technology has considerable potential for use in preparing sodium deoxycholate/phospholipid preMM pellets, with enhanced oral bioavailability for poorly water-soluble drugs.