Analysis of the polymorph changes of a drug candidate

Physicochemical stability and aerosolization performance of dry powder inhalation system containing ciprofloxacin hydrochloride

Antibiotic delivery in form of dry powder inhalation has been studied for possible clinical treatment of respiratory tract infection in the recent years. Dry powder inhalation of ciprofloxacin hydrochloride (CIP) assures local antibacterial activity and comfort of easy application. The aim of this work was to test the stability of co-spray-dried CIP in carrier free system. Since the microparticles in the dry powder system are amorphous and do not contain any stabilizer, the effects of temperature and relative humidity (RH) on the physicochemical properties and aerosolization behavior are very important. Therefore investigation of the role of excipients (such as polyvinyl alcohol (PVA), l-leucine (LEU) and hydroxypropyl-beta-cyclodextrin (CD)) on physicochemical stability and aerosolization performance is essential element prior designing the final dosage form. Stability tests (stress and accelerated) were performed at 40±2°C and 75±5% RH during 6 months. Particle characterization and size measurement - as the most important parameters in aerodynamic behavior - were done by the laser diffraction method, the surface morphology of microparticles was evaluated by scanning electron microscopy (SEM). The physiochemical properties of microparticles were investigated by X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC). The resulting aerodynamic behavior of microparticles was studied by Andersen cascade impactor. The overall stability results (against RH and temperature) showed that microparticles containing CIP and LEU alone and in combination with the other excipients were more stable than those containing PVA or CD alone. In relation to fine particle fraction and mass median aerodynamic diameter (determining the aerosolization parameters), it was found that the particle size and particle shape did not show significant changes after the storage. Among the excipients LEU was found to have many advantages, including relatively simple formulation, enhanced aerosolization behaviour, convenient portability and inherently improved stability. Such a composition may serve as an innovative drug delivery system for the local treatment of respiratory tract infection and cystic fibrosis.

Effects of Temperature and Solvent on the Solid-State Transformations of Pranlukast During Mechanical Milling

Four solid forms of pranlukast (PRS) were obtained during mechanical milling including neat milling (NM) and solvent-drop milling (SDM), which were characterized by various analytical techniques. The effect of milling conditions including 3 milling temperatures and 6 assist solvents on the solid-state transformations of commercial PRS (PRS HH) was systemically investigated. Milling temperature significantly influenced the NM process. A low milling temperature (5°C) led to a complete amorphization of PRS HH, whereas higher milling temperatures (15°C and 30°C) only induced a partial amorphization. The milling at 5°C was proven to be a progressive amorphization process, and the amorphous material showed an increasing stability with prolonged milling time. Amorphous PRS can stay stable under low temperature and relative humidity conditions and showed significantly higher solubilities and faster dissolution rates in both water and pH 6.8 phosphate buffer solution. A total of 6 solvents were used in the SDM experiments. N,N-dimethylformamide and dimethyl sulfoxide should be avoided in the manufacturing process of PRS because corresponding solvates of PRS can be easily generated by SDM of PRS HH with short milling time and small amount of solvents.