Drug product development and pharmacological evaluation of a sparingly soluble novel camptothecin analog for peroral administration.

This work focused on the developmental aspects, pharmacokinetic evaluation, and pharmacological assessment of a drug inclusion complex for a novel camptothecin analog (CA) and 2-hydroxypropyl-ß-cyclodextrin (HP-ß-CD). Camptothecins analog belong to topoisomerase-I inhibitor class of compounds with proven anti-tumor activity but exhibit poor solubility. To enhance solubility a drug inclusion complex with cyclodextrin was developed using a spray-drying process. The powder complex characterized using DSC, XRPD, FT-IR, and ¹H NMR techniques confirmed interaction of cyclodextrin with the CA indicating formation of a true complex wherein the drug is encapsulated in the cyclodextrin cavity. The saturation solubility and dissolution kinetics of drug complex evaluated in a discriminating medium showed significantly higher solubility and faster dissolution as compared to a physical mixture or powder blend comprising of drug and cyclodextrin. Pharmacokinetic (PK) studies in Wistar rats indicated a significant increase in the rate and extent of absorption for the drug complex as compared to a nanoparticulate dispersion that was used as the positive control. Pharmacological activity following peroral administration of drug complex in athymic nude mice with implanted tumors revealed that the tumor inhibition activity was equivalent to commercially available intravenous (IV) formulation with comparable safety profile. These studies demonstrated for the first instance feasibility of developing a safe and efficacious peroral formulation for a sparingly soluble camptothecin analog that may provide another viable, patient compliant, and cost effective option for the treatment of solid tumors.

Solid self-microemulsifying formulation for candesartan cilexetil.

Sparingly, water-soluble drugs such as candesartan cilexetil offer challenges in developing a drug product with adequate bioavailability. The objective of the present study was to develop and characterize self-microemulsifying drug delivery system (SMEDDS) of candesartan cilexetil for filling into hard gelatin capsules. Solubility of candesartan cilexetil was evaluated in various nonaqueous careers that included oils, surfactants, and cosurfactants. Pseudoternary phase diagrams were constructed to identify the self-microemulsification region. Four self-microemulsifying formulations were prepared using mixtures of oils, surfactants, and cosurfactants in various proportions. The self-microemulsification properties, droplet size, and zeta potential of these formulations were studied upon dilution with water. The optimized liquid SMEDDS formulation was converted into free flowing powder by adsorbing onto a solid carrier for encapsulation. The dissolution characteristics of solid intermediates of SMEDDS filled into hard gelatin capsules was investigated and compared with liquid formulation and commercial formulation to ascertain the impact on self-emulsifying properties following conversion. The results indicated that solid intermediates showed comparable rate and extent of drug dissolution in a discriminating dissolution medium as liquid SMEDDS indicating that the self-emulsifying properties of SMEDDS were unaffected following conversion. Also, the rate and extent of drug dissolution for solid intermediates was significantly higher than commercial tablet formulation. The results from this study demonstrate the potential use of SMEDDS as a means of improving solubility, dissolution, and concomitantly the bioavailability.

Spray-drying process optimization for manufacture of drug-cyclodextrin complex powder using design of experiments.

BACKGROUND: Design of experiments (DOE), a component of Quality by Design, is systematic and simultaneous evaluation of variables (process or formulation) to develop a product with predetermined quality attributes. This study presents a case study to understand the effects of process variables in a spray-drying process used in the manufacture of drug-cyclodextrin complex for a drug that is prone to chemical instability at elevated temperature conditions encountered during processing. METHODS: Experiments were designed, and data were collected according to a three-factor, three-level face-centered central composite design. The factors investigated were inlet temperature, spray rate, and batch size. Responses analyzed for computing the interaction effects were drug content, impurities, moisture content, and process yield. The spray-drying process conditions were optimized using DOE to maximize production yields while minimizing moisture content and drug-related impurities. Process validation batches were executed using the optimum process conditions obtained from software Design-Expert((R)) to evaluate both the repeatability and reproducibility of spray-drying technique. RESULTS: Optimization of process variables using DOE resulted in a significant improvement of process yields, above 90% and moisture content below 6% (w/w). The impurities were controlled within acceptable limits. The desirability function used to optimize the response variables and observed responses were in agreement with experimental values. These results demonstrated the reliability of selected model for manufacture of powder complex with predictable quality attributes. CONCLUSION: The study indicates the general applicability of DOE approach to optimize critical process parameters in the manufacture of drug product with desired quality attributes.

Production and in vitro characterization of solid dosage form incorporating drug nanoparticles.

The objective of this study was to develop a tablet formulation of ketoconazole incorporating drug nanoparticles to enhance saturation solubility and dissolution velocity for enhancing bioavailability and reducing variability in systemic exposure. The bioavailability of ketoconazole is dissolution limited following oral administration. To enhance bioavailability and overcome variability in systemic exposure, a nanoparticle formulation of ketoconazole was developed. Ketoconazole nanoparticles were prepared using a media-milling technique. The nanosuspension was layered onto water-soluble carriers using a fluid bed processor. The nanosuspensions were characterized for particle size before and after layering onto water-soluble carriers. The saturation solubility and dissolution characteristics were investigated and compared with commercial ketoconazole formulation to ascertain the impact of particle size on drug dissolution. The drug nanoparticles were evaluated for solid-state transitions before and after milling using differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD). This study demonstrated that tablet formulation incorporating ketoconazole nanoparticles showed significantly faster rate of drug dissolution in a discriminating dissolution medium as compared with commercially available tablet formulation. There was no affect on solid-state properties of ketoconazole following milling. The manufacturing process used is relatively simple and scalable indicating general applicability to enhance dissolution and bioavailability of many sparingly soluble compounds.