Preparation,characterization and pharmacokinetics of 10-hydroxy-camptothecin nanosuspension

10-Hydroxycamptothecin (HCPT) is a broad-spectrum anticancer drug, while its low solubility and instability severely limit its application. In this study, HCPT nanosuspension (HCPT-NSP), also known as nanocrystal, was prepared by micro-precipitationcombined with high-pressure homogenization method. This nanosuspension was characterized by size, shape, zeta potential, drug loading efficiency and in vitro drug release behavior. Preferred formulation and process showed that particle size was (129.8±13.9) nm, PDI was 0.20±0.07, and drug loading efficiency was 36.5%±9.5%. Moreover, HCPT nanocrystal concentration reached(1.35±0.2) mg/mL in HCPT-NSP, which was more than 1000-fold higher than that of HCPT. Transmission electron microscopy (TEM) results showed that the nanosuspension was short rod in shape. X-ray powder diffraction (XRD), thermogravimetric analysis (TGA), derivative thermogravimetric analysis (DTA) and differential scanning calorimetry (DSC) further elaborated the crystal state of the HCPT. The drug concentration-time curve of HCPT-NSP in rats was in accordance with the three-compartment model, showing prolonged half-life. Taken together, our data suggested that HCPT-NSP was a promising drug delivery system.     

白藜芦醇纳米混悬液的制备及固化

目的：制备并固化白藜芦醇纳米混悬液。方法采用反溶剂沉淀法和高压均质法制备白藜芦醇纳米混悬液,冷冻干燥法进行固化。结果采用反溶剂沉淀法制备了粒径为120.3 nm 的白藜芦醇纳米混悬液,固化后的释放度实验结果表明,白藜芦醇的纳米化有力地促进了其体外释放速度。结论制备的纳米混悬液处方简单,可固化并进一步制备为胶囊剂或片剂等其他固体制剂。     

Drug nanocrystals in the commercial pharmaceutical development process

Nanosizing is one of the most important drug delivery platform approaches for the commercial development of poorly soluble drug molecules. The research efforts of many industrial and academic groups have resulted in various particle size reduction techniques. From an industrial point of view, the two most advanced top-down processes used at the commercial scale are wet ball milling and high pressure homogenization. Initial issues such as abrasion, long milling times and other downstream-processing challenges have been solved. With the better understanding of the biopharmaceutical aspects of poorly water-soluble drugs, the in vivo success rate for drug nanocrystals has become more apparent. The clinical effectiveness of nanocrystals is proven by the fact that there are currently six FDA approved nanocrystal products on the market. Alternative approaches such as bottom-up processes or combination technologies have also gained considerable interest. Due to the versatility of nanosizing technology at the milligram scale up to production scale, nanosuspensions are currently used at all stages of commercial drug development, Today, all major pharmaceutical companies have realized the potential of drug nanocrystals and included this universal formulation approach into their decision trees.     

Investigation of preparation parameters to improve the dissolution of poorly water-soluble meloxicam

The rate of dissolution of drugs remains one of the most challenging aspects in formulation development of poorly water-soluble drugs. The meloxicam, a low molecular analgetic for oral administration, exhibits a slow dissolution. To improve the dissolution rate, the drug was formulated in a nanosuspension by using an emulsion–diffusion method, high-pressure homogenization or sonication. Optimization of the technological parameters (organic solvents, stabilizers, homogenization procedure and recovery of particles) allowed the formation of nanosuspensions with a particle size of 200–900 nm. SEM imaging confirmed the nanosized drug particles. Use of an SMCR method on the XRPD patterns of the nanosuspensions revealed the crystalline form of the drug and the strong interaction between meloxicam and the stabilizer. The rate of dissolution of the dried meloxicam nanosuspension was enhanced (90% in 5 min), relative to that of raw meloxicam (15% in 5 min), mainly due to the formation of nanosized particles. These results indicate the suitability of formulation procedure for preparation of nanosized poorly water-soluble drug with significantly improved in vitro dissolution rate, and thus possibly enhance fast onset of therapeutic drug effect.     

Investigation of preparation parameters of nanosuspension by top-down media milling to improve the dissolution of poorly water-soluble glyburide

The objective of this study was to identify and optimize formulation and process variables affecting characteristic and scale-up of nanosuspension manufacturing process on bead mill considering industrial perspective. Formulation factors evaluated were ratio of polymer to drug and ratio of surfactant to drug, whereas process parameters were milling time and milling speed. Responses measured in this study include zeta potential and mean particle size d(90). The test revealed that ratio of polymer to drug and milling speed have significant effect on zeta potential whereas milling time and milling speed have significant effect on the particle size distribution of nanosuspension. The X-ray powder diffraction pattern of drug milled at high and low speed reveals no form conversion when compared with unmilled drug. The formulated nanosuspension has shown a faster dissolution profile (98.97% in 10 min), relative to that of raw glyburide (18.17% in 10 min), mainly due to the formation of nanosized particles. The ANOVA test revealed that there was no significant difference in the dissolution profiles of fresh and aged nanosuspension. These results indicate the suitability of formulation procedure for preparation of nanosized poorly water-soluble drug with significantly improved in vitro dissolution rate and thus possibly enhance fast onset of therapeutic drug effect.     

Production methods for nanodrug particles using the bottom-up approach

This review focuses on bottom-up processes such as precipitation (or crystallisation) and single droplet evaporation to produce nanoparticles containing largely pure therapeutics for pharmaceutical applications. Suitable precipitation techniques involve the use of high-gravity, confined impinging liquid jet mixing, multi-inlet vortex mixing, supercritical fluids, and ultrasonic waves. Droplet evaporation methods are spray-based, including nanospray drying, aerosol flow reactor method, spraying of low-boiling point solvent under ambient conditions and electrospraying of low-electrical conducting solutions. A key to the success of yielding stable nanoparticles in these various techniques is to control the particle growth kinetics through evaporation rate of the droplets or mixing rate during precipitation.