Dt 800

The in vitro drug release of curcumin from the formulated SNEDDS/SMEDDS and from the curcumin extract was performed using USP dissolution apparatus (Erweka, DT 800, Erweka Gmbh, Heusenstamm, Germany). The dissolution medium consisted of 900 mL of freshly prepared simulated intestinal fluid (SIF) without pancreatin (pH 6.8) maintained at 37 °C, the paddle speed was set at 100 rpm. From the different SNEDDS/SMEDDS–curcumin formulations, an amount equivalent to 20 mg of the curcumin was filled in a hydroxypropyl methylcellulose (HPMC) (Capsugel, Inc., Morristown, NJ, USA) capsule size “0”. Aliquots (5 mL) from the dissolution medium were withdrawn at regular time intervals (5, 15, 30, 60, 90, 120 and 180 min) using a calibrated disposable syringe, while the volume of the dissolution medium was kept at 900 mL by adding fresh medium [33 (link),51 (link)]. The samples were filtered through a membrane filter of 0.45 μm pore size and the curcumin concentration was monitored via a spectrophotometric method at 425 nm using UV spectrophotometer (Shimadzu, Tokyo, Japan, serial number: A124256). Finally, the cumulative amount of curcumin released was determined. All measurements were done in triplicate.

Three random samples were taken for dissolution tests from every composition (V1-V3, preparation steps are described in Section 2.2). Nine hundred milliliters of hydrochloric acid media was used for the dissolution tests (pH = 1.2 without pepsin) using an Erweka DT 800 dissolution tester (rotating paddle method, 75 rpm and 37 °C). Samples (3 mL) were taken after 5, 15, and 30 min, and 1, 2, 3, 4, 5, 6, 7, 8, and 10 h and filtered through a 0.22 μm PES membrane syringe filter. The verapamil content of the samples was determined with a UV/VIS spectrophotometer (Shimadzu UV 1601, Shimadzu Corp. Kyoto, Japan) at 278 nm after dilution with a pH 1.2 buffer. Floatation was checked visually at regular intervals.

The study was performed using a vertical diffusion cell (Enhancer cell, Erweka, Langen, Germany) and a paddle dissolution apparatus DT800 (Erweka, Langen, Germany) equipped with a built-in autosampler. The stirring rates of 50, 100 and 150 rpm were used. The Enhancer cell with the mounted modified gelatin film is shown in Figure 2.
The film selected for the test was gelatin + Aquacoat + carrageenan (GAC), the same as for disintegration tests. The diffusion cell was filled with 2.5 mL of a 1% diclofenac solution in PEG 400 (the amount of diclofenac sodium was 25 mg). Then the investigated film (cut to a circle of 3 cm in diameter) was carefully placed on the top of the solution and secured with a sealing ring and a screw cap; the active surface was 4.15 cm². The test was performed in 900 mL of 0.1 M HCl for 120 min followed by 900 mL phosphate buffer pH 6.8 for 60 min.
Sampling of the acceptor fluid was performed every 15 min in the acid phase, and every 5 min in the buffer phase. Quantification of diclofenac was performed spectrophotometrically at 276 nm wavelength. The study was performed in triplicates.

Dissolution studies of Cardiazem^® 60 mg tablets were performed using a USP 2 dissolution apparatus (DT 800 Erweka GmbH, Heusenstamm, Germany) at 75 rpm. The dissolution medium (ultrapure water, 900 mL) was deaerated and maintained at 37 ± 0.5 °C. Aliquots of 5 ± 0.1 mL were withdrawn at 10, 15, 20, 30, 60, 120, and 180 min, and immediately replaced with an equal volume of fresh medium maintained at the same temperature. The samples were filtered through a 0.45 μm Teflon^® filter, and the drug concentrations were determined by measuring the absorbance of each sample at 237 nm on a V-530 UV-VIS spectrophotometer (JASCO Ltd., Tokio, Japan). Diltiazem concentrations were calculated from linear calibration curves. Dissolution data for each compound are reported as mean values of 12 replicates, and the coefficient of variation (CV%; [mean value/standard deviation] × 100%) was calculated.

The dissolution rate was determined using USP basket Apparatus I (dissolution tester ERWEKA DT 800), in 500 mL of distilled water. The apparatus was settled at 37 ± 0.5 °C, with a rotating speed of 100 rpm and the test was performed on 6 tablets of each formulation. The amount of dissolved calcium lactate was determined after 30 min, by the titrimetric method. After 30 min, 300 mL of each vat were filtered. To 100 mL of filtered solution, 150 mL of water, 2 mL of 3 N hydrochloric acid and 15 mL of 1 N sodium hydroxide were added and stirred. 300 mg of blue hydroxynaphthol were added and titrated with 0.05 M edetate disodium solution to blue [61 ].

Different self-emulsifying combinations have been formulated by the water and oil dilution method with various previously tested tensides and co-tensides [15 (link)]. The compositions are listed in Table 1. Tenside components were mixed at 37 °C by Schott Tritronic dispenser (SI Analytical, Mainz, Germany) combined with Radelkis OP-912 magnetic stirrer (Radelkis, Budapest, Hungary). The applied concentrations of cytostatic drugs were dissolved in the systems at room temperature by permanent agitation. To evaluate any signs of phase separation, the mixtures were equilibrated for 24 h. An Erweka DT800 rotating paddle apparatus (Erweka GmbH, Heusenstamm, Germany) was used to evaluate the efficiency of self-emulsification of different mixtures. One gram of each mixture was added to 200 mL of distilled water with gentle agitation condition provided by a rotating paddle at 70 rpm and at a temperature of 37 °C. The process of self-emulsification was visually monitored for the rate of emulsification and for the appearance of the produced emulsions. The visual properties registered against the increment of the applied surfactant component in Ternary triangular diagrams. Plotting points of preferential combinations were selected according to cartesian coordinate calculation.

The release of amiodarone from six tablets was evaluated using a USP 2 dissolution apparatus (DT 800 Erweka GmbH) at 100 rpm. The dissolution medium was sodium lauryl sulfate 10 g/L in ultrapure water (1,000 ml). Samples of 5 ± 0.1 ml were collected at 5, 15, 30, 45, and 60 min and subsequently replaced with an equal volume of medium. AMD concentrations were determined at 242 nm on a V-530 UV-VIS spectrophotometer (JASCO Ltd., Tokyo, Japan).