density

BULK DENSITY & TAPPED DENSITY: 

PREPARED BY: NAITIK G. THAKKAR M.PHARM (PHARMACEUTICS) DDPC 1 BULK DENSITY & TAPPED DENSITY USP GUIDED BY: MR. JAYMIN PATEL ASSISTANT PROFESSOR DDPC

BULK DENSITY: 

BULK DENSITY Bulk density is determined by measuring the VOLUME of a known MASS of powder sample that has been passed through a screen into a graduated cylinder (Method - I ) or through a volume-measuring apparatus into a cup (Method - II ) 2 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC.

METHOD – I Measurement in a Graduated Cylinder: 

METHOD – I Measurement in a Graduated Cylinder Unless otherwise specified, pass a quantity of material sufficient to complete the test through a 1.00-mm (No. 18) screen to break up agglomerates that may have formed during storage into a dry 250-mL cylinder introduce, without compacting, approximately 100 g of test sample, M, Weighed with 0.1% accuracy. If it is not possible to use 100 g , the amount of the test sample and the volume of cylinder may b modified and the test conditions specified with results. Select a sample mass having an untapped apparent volume of 150 to 250 ml. A 100 ml cylinder is used for apparent volumes between 50 ml and 100 ml. 3 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC.

Slide 4: 

Carefully level the powder without compacting , if necessary, and read the unsettled apparent volume , V o , to the nearest graduated unit. Calculate the BULK DENSITY in g per mL, by formula. [Generally replicate determinations are desirable for the determination of this property.] 4 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC. (M) / ( V o )

METHOD – II Measurement in a Volumeter: 

METHOD – II Measurement in a Volumeter Apparatus in figure.1 , conforming to the dimensions in ASTM B329-90 (Scott Volumeter), consists of a top funnel fitted with a 1.00 mm (No. 18) screen OR the screen opening specified in the individual monograph. The funnel is mounted over a baffle box containing four glass baffle plates over which the powder slides and bounces as it passes at the bottom of the baffle box is a funnel that collects the powder and allows it to pour into a cup of specified capacity mounted directly below it. The cup may be CYLINDRICAL (25.00 ± 0.05 ml volume with inside diameter of 30.00 ± 2.00 mm) or a SQUARE (16.39 ± 0.05 ml volume with inside dimensions of 25.4 ± 0.076 mm) 5 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC.

Slide 6: 

6 Figure 1. Scott Volumeter

PROCEUDRE: 

PROCEUDRE Allow an excess of powder to flow through the apparatus into the sample receiving cup until it overflows, using a minimum of 25 cm 3 of powder with the SQUARE cup and 35 cm 3 of powder with CYLINDRICAL cup . Carefully scrape excess powder from the top of the cup by smoothly moving the edge of the blade of a spatula perpendicular to and in contact with the top surface of the cup, taking care to keep the spatula perpendicular to prevent packing or removal of powder from the cup. Remove any material from the sides of the cup, and determine the WEIGHT , M , of the powder to the nearest 0.1% accuracy. Calculate the BULK DENSITY , in g per mL , by formula. 7 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC. (M) / (V o )

TAPPED DENSITY: 

TAPPED DENSITY TAPPED density is achieved by mechanically tapping a measuring cylinder containing a powder sample. After observing the initial volume , the cylinder is mechanically tapped, and volume readings are taken until little further volume change is observed. The mechanical tapping is achieved by raising the cylinder and allowing it to drop under its own weight a specified distance by either of two methods as described below. Devices that rotate the cylinder during tapping may be preferred to minimize any possible separation of the mass during tapping down. 8 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC.

METHOD - I: 

METHOD - I Unless otherwise specified, pass a quantity of material sufficient to complete the test through a 1.00-mm (NO. 18) screen to break up agglomerates that may have formed during storage, Into a dry 250-mL glass graduated cylinder (readable to 2 mL) weighing 220 ± 44 g and mounted on a holder weighing 450 ± 10 g introduce, without compacting, approximately 100 g of test sample, M, weighed with 0.1% accuracy. If it is not possible to use 100 g, the amount of the test sample may be reduced and the volume of the cylinder may be modified by using a suitable 100 ml graduated cylinder (readable to 1 mL) weighing 130 ± 16g and mounted on a holder weighing 240 ± 12 g . The modified test conditions are specified with the results. 9 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC.

Slide 10: 

Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC. 10 Carefully level the powder without compacting, if necessary , and read the unsettled apparent volume, Vo, to the nearest graduated unit. Mechanically tap the cylinder containing the sample by raising the cylinder and allowing it to drop under its own weight using a suitable mechanical tapped density tester that provides a fixed drop of 14 ± 2 mm at a nominal rate of 300 drops per minute . Unless otherwise specified, tap the cylinder 500 times initially and measure the tapped volume, Va, to the nearest graduated unit. Repeat the tapping an additional 750 times and measure the tapped volume, Vb, to the nearest graduated unit. (NOTE- fewer taps may be appropriate, if validated, for some powders)

Slide 11: 

11 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC. If the difference between the two volumes is less than 2%, V b is the final tapped volume, V f . Repeat in increments of 1250 taps, as needed, until the difference between succeeding measurements is less than 2%. Calculate the TAPPED DENSITY , in g per mL, by formula: Generally replicate determinations are desirable for the determination of this property. ( M )/( V f )

METHOD - II: 

METHOD - II Proceed as directed under Method-I except that a suitable mechanical tapped density tester that provides a fixed drop of 3 mm (± 10%) at a nominal rate of 250 drops per minute is used. 12 Naitik Thakkar M.Pharm ( Pharmaceutics ) DDPC.