A comparison of the dissolution rates of caffeine tablets in a rotating-basket with those in a Sartorius dissolution tester

Uncoated caffeine tablets of four different hardnesses were tested for dissolution rate by the Sartorius (S.S. method) and by the rotating basket method of the U.S.P. XVIII. In both methods the dissolution rate decreased with increasing hardness, and the rate obtained with the S.S. method was always less than that by the U.S.P. method. This result cannot be explained as being due only to the difference in the volume of dissolution medium. Also it was difficult to ensure that the characteristic changes in the process of dissolution paralleled the curves obtained from a plot of % caffeine dissolved vs time. Accordingly, the dissolution rate constants were calculated from the slope of each straight line in a plot of In W^∞/(W^∞ - W) vs time.     

Clinical study of transitional cell carcinoma of the prostate associated with bladder transitional cell carcinoma

BACKGROUND: Transitional cell carcinoma of the prostate in patients with bladder cancer appears to influence the prognosis and affects the decision about therapeutic modality. Therefore, it is important to characterize transitional cell carcinoma associated with bladder cancer. METHODS: From April 1980 to December 1998, 81 male patients underwent total cystoprostatectomies for transitional cell carcinoma of the bladder. The 81 cystoprostatectomy specimens were examined to clarify the characteristics of prostatic involvement by transitional cell carcinoma. The extent, origin, mode of spread and risk factor of prostatic involvement as well as the prognosis were investigated. In 13 of 15 patients with prostatic involvement the prostate was examined by sequential step sections. RESULTS: Prostatic involvement was observed in 15 of 81 patients (18.5%). Prostatic urethral involvement, invasion to prostatic duct/acinus, prostatic stromal invasion and extraprostatic extension and/or seminal vesicle involvement were recognized in 12 (80%), 14 (93.3%), six (40%), and five (33.3%) of the 15 patients, respectively. Twelve of the 15 patients (80%) with prostatic involvement had papillary or non-papillary tumors (i.e. carcinoma in situ) both in the prostatic urethra and prostatic duct. In 10 of these 12 patients (88.3%), there was contiguity between prostatic urethral and ductal tumors. Seven of the 23 patients (30.4%) with carcinoma in situ of the bladder showed prostatic involvement, which increased to 50% in the presence of carcinoma in situ of the trigone or bladder neck. CONCLUSIONS: Eighty per cent of the patients with prostatic involvement showed papillary or non-papillary tumors both in the prostatic urethra and prostatic duct. There was a high level of contiguity between both tumors. Patients with carcinoma in situ of the trigone or bladder neck revealed significantly higher incidence of prostatic involvement.