Transformation of ABT-199 Nanocrystal Suspensions into a Redispersible Drug Product-Impact of Vacuum Drum Drying, Spray Drying and Tableting on Re-Nanodispersibility.

The present study compared vacuum drum drying (VDD) and conventional spray drying (SD) for solidifying crystalline ABT-199 nanosuspensions into redispersible oral drug products. The aim was to optimize formulation compositions and process conditions to maintain nanoparticle size after tablet redispersion. The impact of drug load (22%, 33%, 44%) and type of drying protectant (mannitol, mannitol/trehalose mix (1:1), trehalose) on redispersibility and material powder properties were investigated. Moreover, compression analysis was performed assessing the influence of compaction pressure on primary nanocrystal redispersibility and tablet disintegration. Higher drug loads and lower drying protectant levels resulted in particle growth, confirming a drug load dependence on redispersibility behavior. Notably, all drying protectants showed similar protection properties at properly chosen drying process parameters (Tg-dependent), except when VDD was used for mannitol formulations. Differences between the applied drying processes were observed in terms of downstream processing and tabletability: mannitol-containing formulations solidified via VDD showed an improved processability compared to formulations with trehalose. In conclusion, VDD is a promising drying technique that offers advantageous downstream processability compared to SD and represents an attractive novel processing technology for the pharmaceutical industry. As demonstrated in the present study, VDD combines higher yields with a leaner manufacturing process flow. The improved bulk properties provide enhanced tabletability and enable direct compression.

Transformation of Ritonavir Nanocrystal Suspensions into a Redispersible Drug Product via Vacuum Drum Drying.

The present study explored vacuum drum drying (VDD) as potential drying technique for the solidification of crystalline ritonavir nanosuspensions prepared by wet-ball milling. In detail, the impact of drying protectants (mannitol, lactose, trehalose) added to the ritonavir nanosuspension was assessed in dependence of the drum temperature with respect to processibility via VDD, resulting intermediate powder properties, remaining nanoparticulate redispersibility and crystallinity. A clear impact of the glass transition temperature (Tg) of the drying protectant on the redispersibility/crystallinity of the VDD intermediate was observed. Increased Tg of the drying protectant was associated with improved redispersibility/crystallinity at a defined drum temperature. Consequently, the high Tg-substance trehalose and lactose showed a better performance than mannitol at higher drum temperatures. However, the processability and related powder properties were not in accordance with this observation. Mannitol containing formulations showed superior processibility to those containing trehalose/lactose. Moreover, the impact of the tableting and encapsulation process on the redispersibility of the VDD intermediate was studied for a selected formulation. Neither process demonstrated a negative impact on redispersibility. In conclusion, vacuum drum drying is a promising drying technique for the solidification of nanosuspensions to result in dried powder still containing ritonavir nanoparticles while demonstrating acceptable to good downstream processibility to tablets/capsules.

Synthesis and Characterization of Biodegradable Poly(butyl cyanoacrylate) for Drug Delivery Applications.

Poly(butyl cyanoacrylate) (PBCA) is a biodegradable and biocompatible homopolymer which is used as a carrier matrix for drug delivery systems in the pharmaceutical industry. Typically, polymerization is carried out under aqueous conditions and results in molecular weights are mostly lower than 3000 g/mol due to the instability of the high molecular weight PBCA. However, the stability of polymer excipients is a major prerequisite for drug product development in the pharmaceutical industry. In this work, a reliable polymer synthesis strategy for PBCA was designed to control the molecular weight in a nonaqueous polymerization environment. The anionic polymerization process and the impact of key synthesis parameters were investigated. The results confirmed that the previously postulated depolymerization-repolymerization process (DPRP) in the literature can be used to tailor the molecular weight of PBCA. The amount of sodium methoxide present during the polymerization proved to be the key parameter to control the DPRP and the molecular weight as desired. In addition, it was discovered that end-capping the PBCA chain suppressed the DPRP and prevented monomer release by depriving the PBCA of its living character. Thus, neat PBCA polymer with varying molecular weights determined by Advanced Polymer Chromatography™ as well as end-capped PBCA were synthesized, and the improvement of the chemical and shelf-life stability were confirmed using NMR.

Development and lyophilization of itraconazole loaded poly(butylcyanoacrylate) nanospheres as a drug delivery system.

Itraconazole is a poorly soluble drug which is used in the treatment of systemic fungal infections. However, there is little reported literature about itraconazole loaded delivery systems used for targeted delivery. Therefore, poly(butyl cyanoacrylate) nanospheres (PBCA-NSP) have been developed as a potential delivery system for transport of itraconazole. One possible application of itraconazole loaded PBCA-NSP could be to treat cryptococcal meningitis. An oil-in-water (o/w) emulsion solvent evaporation was performed for formulation generation. Manufacturing optimization was achieved using design of experiments (DoE) methodology. The average size of PBCA-NSPs varied between 60 and 80 nm. Encapsulation efficiency (EE (%)), absolute drug loading (AL (%)) and release rate of itraconazole from PBCA-NSP in vitro were measured by reversed phase high-performance liquid chromatography (RP-HPLC). EE of 87% could be achieved when the AL of 17.6% was intended. Lyophilization of itraconazole loaded PBCA-NSP was needed to increase the stability of formulations, which was achieved by evaluating different sugar cryoprotectants. In this study, PBCA-NSPs were successfully generated as a delivery system for itraconazole providing a promising approach to improve the therapy of fungal infections of specific organs such as the brain infection cryptococcal meningitis.