ABSTRACT
Objective To explore the change in anatomical volume during intensity?modulated radiotherapy (IMRT) for different stages of nasopharyngeal carcinoma (NPC) and its influence on dose distribution, and to assess the necessity to modify the IMRT plan. Methods Twenty?four patients with newly diagnosed NPC who received IMRT and chemotherapy were enrolled in the study, and were divided into early?intermediate group ( 12 cases ) and locally advanced group ( 12 cases ) according to the 2008 staging system for NPC. Each patient had a repeated CT scan at week 5 of radiotherapy, and target volume and organs at risk ( OAR) were contoured. The dose distribution of the original plan shown on CT was calculated. Changes in target volume, OAR anatomical volume, and dose distribution were analyzed, and paired t?test and Spearman correlation analysis were performed. Results In the early?intermediate group, gross target volume of neck positive lymph nodes (GTVnd) was reduced during radiotherapy (P=0. 059), and gross target volume of nasopharynx ( GTVnx ) , high?risk clinical target volume ( CTV1 ) , and parotid volume were reduced significantly during radiotherapy ( P= 0. 001, 0. 012, 0. 002, and 0. 000, respectively) . In locally advanced group, GTVnx , GTVnd , CTV1 , and parotid volume were significantly reduced during IMRT (P=0. 000, 0. 000, 0. 003, 0. 003, and 0. 000, respectively). Compared with the values before radiotherapy, the parotid dose increased significantly in the two groups during IMRT ( P=0. 044, 0. 026, 0. 033, and 0. 026, respectively;P=0. 024, 0. 016, 0. 030, and 0. 015, respectively) , and the increase in GTVnd dose was observed in the locally advanced group ( P= 0. 029 and 0. 049 ) . Conclusions It is recommended to perform another CT scan for patients with locally advanced NPC at week 5 of radiotherapy and formulate a new IMRT plan to maintain target volume dose and guarantee a safe parotid dose.
ABSTRACT
This study was aimed to prepare solid dispersions of Acanthopanax leaves total flavonoids in order to im-prove its bioavailability. PEG4000, PEG6000, F68, PVPK30 were used as carrier materials in the preparation of four different types of solid dispersion to screen the best type of carrier material and evaluate the amount of carrier mate-rial and its influence on the drug dissolution. Rutin was used as reference substance. NaNO2-Al(NO3)3-NaOH was used as the color system, with a UV spectrophotometer measured absorbance at 500 nm. The dissolution characteris-tics of different proportions of solid dispersions were examined in vitro. The results showed that compared with raw material, the in vitro drug release rate with PVPK30 as carrier material in the obtained solid dispersion of the pro-portion of the raw material was significantly improved, and the cumulative release rate was also increased significant-ly. It was concluded that the solid dispersion prepared by solvent method significantly improved in vitro drug release in water.
ABSTRACT
Objective To explore self-emulsifying particle size characterization methods and compare the regularity of various methods. Methods By setting the clarity level of turbidity standard solution, with two less soluble drugs-diterpene lactone compounds Chuanhuning and dihydropyridine drug nifedipine as model drugs, 10-12 clarity level prescriptions were selected from six different ternary phase diagram. Laser particle size scanner was used to determine the particle size, and UV-visible spectrophotometry to determine its absorbance. Three methods of particle size characterization rules were compared by drawing charts. Results There was a positive correlationship among droplet particle size, absorbance and clarity grade of emulsion formed by prescription in the same phase diagram. But, there was no regularity among droplet particle size, absorbance and clarity grade of emulsion formed by prescription in different phase diagram. Conclusion The droplet particle size of emulsion formed by prescription containing the same drugs and excipients in different proportions can be compared by clarity with visual method or absorbance with UV-visible spectrophotometer.