Fabrication of potential gastroretentive microspheres of itraconazole for stomach-specific delivery: Statistical optimization and in vitro evaluation

The premise of the study was to develop and optimize multiple unit gastroretentive microspheres of itraconazoleto prolong its localization in the stomach and analyzed using response surface methodology. The emulsion solventdiffusion evaporation method was used to prepare hollow microsphere of ethyl cellulose and Eudragit RS100 as lowdensity shell-forming polymers. The experimental design matrix was prepared using a central composite design tostudy the effect of various process parameters over response variables. The optimized microspheres showed a particlesize of 285.1µm, drug entrapment efficiency of 86.8%, buoyancy of 51.1%, and cumulative drug release of 77.80%.The experimental responses were in good harmony with the predicted values. The compatibility between drug andexcipients was determined by Fourier-transform infrared and differential scanning calorimetry analysis. The resultssignify that gastroretentive hollow microspheres are a promising vehicle to extend the retention time of itraconazolein the upper GI tract, and it can be floated in an acidic medium for a prolonged period.

Binding pattern of 125Iodine thyroxine and tri-iodothyronine in skin and liver tissues of spotted munia, Lonchura punctulata: Co-relation to seasonal cycles of breeding and molting.

Prevalent notion about thyroid hormones is that thyroxine (T4) is a mere precursor and physiological effects of thyroid hormones are elicited by tri-iodothyronine (T3) after mono-deiodination of T4. Earlier studies on feather regeneration and molt done on spotted munia L. punctulata suggest that T4 (mono-deiodination suppressed by iopanoic acid and thyroidectomized birds) is more effective than T3 in inducing feather regeneration. The binding pattern of 125I labeled T4 and T3 has been investigated in the nuclei prepared from skin and liver tissues (samples obtained during different months) of spotted munia using scatchard plot analysis. The results show that binding capacity (Bmax – pmole/80 µgm DNA) of 125I-T3 to nuclei of skin was significantly higher in November as compared to April and June, whereas the binding affinity (Kd-10-9M-1) was significantly lower in November as compared to April and June. During November, Bmax for binding of T3 and T4 did not vary in liver and skin nuclei but Kd varied significantly. Binding capacity of 125I- T3 to skin and liver did not vary but binding affinity of 125I- T4 to skin was approximately 7 times higher than that of liver. The results suggest that T4 does show a variation in binding pattern that co-relates to the molting pattern of spotted munia. These variations might play important role in different physiological phenomenon in this tropical bird. The experiments do point towards the possibility of independent role of T4 as a hormone, however, further experiments need to be done to ascertain the role of T4 in this model and work out the exact molecular mechanism of action.