Syed Muhammad Hassan Shah 1 , Farhat Ullah 2 , Shahzeb Khan 2 , 3 , Syed Muhammad Mukarram Shah 4 , Marcel de Matas 5 , Zahid Hussain 6 , Muhammad Usman Minhas 7 , Naser M AbdEl-Salam 8 , Khaled Hafez Assi 3 , Mohammad Isreb 3
24 November 2016
Artemether (ARTM) is a very effective antimalarial drug with poor solubility and consequently low bioavailability. Smart nanocrystals of ARTM with particle size of 161±1.5 nm and polydispersity index of 0.172±0.01 were produced in <1 hour using a wet milling technology, Dena ® DM-100. The crystallinity of the processed ARTM was confirmed using differential scanning calorimetry and powder X-ray diffraction. The saturation solubility of the ARTM nanocrystals was substantially increased to 900 µg/mL compared to the raw ARTM in water (145.0±2.3 µg/mL) and stabilizer solution (300.0±2.0 µg/mL). The physical stability studies conducted for 90 days demonstrated that nanocrystals stored at 2°C–8°C and 25°C were very stable compared to the samples stored at 40°C. The nanocrystals were also shown to be stable when processed at acidic pH (2.0). The solubility and dissolution rate of ARTM nanocrystals were significantly increased ( P<0.05) compared to those of its bulk powder form. The results of in vitro studies showed significant antimalarial effect ( P<0.05) against Plasmodium falciparum and Plasmodium vivax. The IC 50 (median lethal oral dose) value of ARTM nanocrystals was 28- and 54-fold lower than the IC 50 value of unprocessed drug and 13- and 21-fold lower than the IC 50 value of the marketed tablets, respectively. In addition, ARTM nanocrystals at the same dose (2 mg/kg) showed significantly ( P<0.05) higher reduction in percent parasitemia (89%) against P. vivax compared to the unprocessed (27%), marketed tablets (45%), and microsuspension (60%). The acute toxicity study demonstrated that the LD 50 value of ARTM nanocrystals is between 1,500 mg/kg and 2,000 mg/kg when given orally. This study demonstrated that the wet milling technology (Dena ® DM-100) can produce smart nanocrystals of ARTM with enhanced antimalarial activities.