Improved dissolution and pharmacokinetic behavior of cyclosporine A using high-energy amorphous solid dispersion approach

Klucel™ EF and ELF polymers for immediate-release oral dosage forms prepared by melt extrusion technology

The objective of this research work was to evaluate Klucel™ hydroxypropylcellulose (HPC) EF and ELF polymers, for solubility enhancement as well as to address some of the disadvantages associated with solid dispersions. Ketoprofen (KPR), a Biopharmaceutics Classification System class II drug with poor solubility, was utilized as a model compound. Preliminary thermal studies were performed to confirm formation of a solid solution/dispersion of KPR in HPC matrix and also to establish processing conditions for hot-melt extrusion. Extrudates pelletized and filled into capsules exhibited a carrier-dependent release with ELF polymer exhibiting a faster release. Tablets compressed from milled extrudates exhibited rapid release owing to the increased surface area of the milled extrudate. Addition of mannitol (MNT) further enhanced the release by forming micro-pores and increasing the porosity of the extrudates. An optimized tablet formulation constituting KPR, MNT, and ELF in a 1:1:1 ratio exhibited 90% release in 15 min similar to a commercial capsule formulation. HPC polymers are non-ionic hydrophilic polymers that undergo polymer-chain-length-dependent solubilization and can be used to enhance solubility or dissolution rate of poorly soluble drugs. Dissolution/release rate could be tailored for rapid-release applications by selecting a suitable HPC polymer and altering the final dosage form. The release obtained from pellets was carrier-dependent and not drug-dependent, and hence, such a system can be effectively utilized to address solubility or precipitation issues with poorly soluble drugs in the gastrointestinal environment.

Polymeric nanocapsules with SEDDS oil-core for the controlled and enhanced oral absorption of cyclosporine

Self-microemulsifying drug delivery system (SEDDS) cored-polymeric nanocapsules (NC) were fabricated using emulsion diffusion method for the controlled oral absorption of the poorly water soluble drug, cyclosporine. Poly-dl-lactide (PDLLA) was used as the shell-forming polymer. The NCs in different polymer/oil ratios (from 25/125 to 125/125) were prepared following a solvent-diffusion method. Especially, the SEDDS oil-core compositions, which can form microemulsions on dispersion, were selected based on a pseudo-phase diagram study and further optimized based on the solubility and permeability studies. The prepared NCs were with a mean diameter of 150-220 nm and 9.4-4.5% w/w drug loading. In vivo study in rats showed that the optimized NC(50/125) and NC(100/125) released the drug in controlled way as well as enhanced the bioavailability significantly with AUC(0-24h) values of 14880.3±1470.6 and 12657.8±754.5 ng h/ml, respectively, compared to that of SEDDS-core solution (9878.9±409.6 ng h/ml). Moreover it was observed that the NCs maintained blood concentration of cyclosporine (>500 ng/ml) for 14-20 h but in the case of control formulation it was only 7.33 h. Our results suggest that the prepared NCs could be a potential carrier for the oral controlled release formulation of cyclosporine.

Inhalable dry-emulsion formulation of cyclosporine A with improved anti-inflammatory effects in experimental asthma/COPD-model rats

The main purpose of the present study was to develop a novel respirable powder (RP) formulation of cyclosporine A (CsA) using a spray-dried O/W-emulsion (DE) system. DE formulation of CsA (DE/CsA) was prepared by spray-drying a mixture of erythritol and liquid O/W emulsion containing CsA, polyvinylpyrrolidone, and glyceryl monooleate as emulsifying agent. The DE/CsA powders were mixed with lactose carriers to obtain an RP formulation of DE/CsA (DE/CsA-RP), and its physicochemical, pharmacological, and pharmacokinetic properties were evaluated. Spray-dried DE/CsA exhibited significant improvement in dissolution behavior with ca. 4500-fold increase of dissolution rate, and then, nanoemulsified particles were reconstituted with a mean diameter of 317 nm. Laser diffraction analysis on the DE/CsA-RP suggested high dispersion of DE/CsA on the surface of the lactose carrier. Anti-inflammatory properties of the inhaled DE/CsA-RP were characterized in antigen-sensitized asthma/COPD-model rats, in which the DE/CsA-RP was more potent than the RP formulation of physical mixture containing CsA and erythritol in inhibiting inflammatory responses, possibly due to the improved dissolution behavior. Pharmacokinetic studies demonstrated that systemic exposure of CsA after intratracheal administration of the DE/CsA-RP at a pharmacologically effective dose (100 μg-CsA/rat) was 50-fold less than that of the oral CsA dosage form at a toxic dose (10 mg/kg). From these findings, use of inhalable DE formulation of CsA might be a promising approach for the treatment of airway inflammatory diseases with improved pharmacodynamics and lower systemic exposure.