Evaluation of the properties of ethylcellulose-cellulose triacetate microcapsules containing theophylline prepared by different microencapsulation techniques.

Using cellulose triacetate as an added complementary coating material in preparing sustained-release ethylcellulose-cellulose triacetate microcapsules of theophylline, three microencapsulation techniques were investigated. Ethylcellulose-cellulose triacetate composite microcapsules, ethylcellulose-cellulose triacetate dual-walled microcapsules and ethylcellulose microcapsules containing cellulose triacetate matrices were prepared using the non-solvent addition phase separation method. The effects of cellulose triacetate on the release of theophylline from the different ethylcellulose-cellulose triacetate microcapsules were obtained from dissolution studies. The results showed that the release rates of ethylcellulose-cellulose triacetate microcapsules were slower than those obtained from the ethylcellulose microcapsules prepared with similar core to wall ratios. The ethylcellulose microcapsules containing cellulose triacetate matrices had longer release half-times and smaller surface areas than the other capsule preparation. The release patterns of theophylline from the different ethylcellulose-cellulose triacetate microcapsules fitted first-order kinetics. Scanning electron micrographs showed that the surfaces of various ethylcellulose-cellulose triacetate microcapsules were different from those of theophylline, cellulose triacetate matrices of cellulose triacetate microcapsules, and that the surface morphology of ethylcellulose-cellulose triacetate microcapsules was affected by the preparative method.

Utilization of the Wallstent for the treatment of innominate vein obstruction: a case report.

Debilitating obstruction of the large veins may occur from external compression, neointimal proliferation or thrombosis. Appropriate interventions are contingent upon the underlying etiology and the local vascular anatomy. A case of innominate vein obstruction is presented illustrating the available intravascular therapeutic options, with special emphasis placed on intravenous stenting.

High incidence of renal artery stenosis in patients with coronary artery disease.

The incidence of renal artery stenosis (RAS) in patients with coronary artery disease (CAD) has not been well documented. Over a 9-month period, 196 patients who underwent coronary angiography because of clinically suspected CAD had routine nonselective renal cine or digital subtraction angiography. There were 68 females and 128 males with a mean age of 63 years (range 35-85). Angiographically significant CAD was present in 152 patients (78%). Of the total patient cohort, 29 patients (15%) had mild RAS (< 50%), and 36 patients (18%) had significant RAS (> or = 50%). In patients with normal coronary arteries, only three patients (7%) had RAS. Thirty-three patients (92%) with severe RAS also had CAD. Of these 33 patients, 45% had hypertension, 30% had hyperlipidemia, 24% had diabetes mellitus, 24% had renal insufficiency (creatinine > or = 1.5), and 51% were smokers. In addition, it was noted that 20 of these patients (61%) had two or more of the above-listed clinical parameters. However, univariate analysis using the chi-square test revealed that only CAD (22% P < 0.03) and renal insufficiency (29% P < 0.15) were reliable clinical predictors of RAS. In conclusion, RAS is a frequent finding in patients with CAD, particularly when renal insufficiency is also present.