Tablet defects

types of tablet defects, reasons, prevention methods.

1. TABLET DEFECTS PREPARED BY: K. ARSHAD AHMED KHAN M.Pharm , ( Ph.D ) Dept. of Pharmaceutics RIPER.

2. PH 101.76 2 Picking & sticking Capping & lamination Mottling Double impression Poor mixing Poor flow Weight variation Hardness variation Punch variation Manufacturing defects in tablets :

3. PH 101.76 3 Defect Reasons Correction 1. Picking and sticking Picking- Material adherence to punch face causes removal of material from tablet surface. Sticking - adherence of tablet material to the die walls. Causes difficulty in ejection of tablet. Improper designing of engraved punches. Poor maintenance of punches surfaces. Use of worn out punches and dies. Under dried granules. Proper designing of punches. Chrome plating of punch surfaces. Proper quantity of anti-adherents. Adequate drying of granules.

4. PH 101.76 4 Defect Reasons Correction 2. Capping & lamination: Capping - partial or total separation of top or bottom portions of the tablet. Lamination - separation of tablet in two or more layers. entrapment of air in granules. excess fines in granules. excessive drying of granules. use of defective punches and dies. reduce the percentage of fines in granules. maintenance of desired amount of moisture in granules. replacement of defective punches & dies.

5. PH 101.76 5 Defect Reasons Correction 3. Mottling: U neven distribution of colour on the surface of tablets. difference in the colours of drugs & additives. migration of colour to the surface of granules during drying. improper distribution of colours in powder bulk. larger particles of dye/ lake. using a dye that can mask the colours of all the ingredients. drying the granules at low temperature. using the dyes/ lakes of very fine particle size.

6. PH 101.76 6 4. Double impression : Double impression of monogram on lower surface of tablet. Occurs where the lower punch have a monogram. Reasons - free rotational travel of lower punch after compression causes a new lighter impression on the bottom of the tablet . Tablet compression machines using 2 compression stages. Correction- By controlling the undesirable movement of punches . Using new punches with anti-turning devices.

7. 5. Poor mixing: Reason: Ununiform distribution of lubricant and glidant . Reduced mixing time during lubricant addition. Prevention: Adequate mixing of lubricant.

8. 6. Poor Flow: Improper flow of powder from hopper to die cavity leading to incomplete filling of die cavity. Reasons: Particulate solids moving under gravity are subjected to uneven pressure form mass above and along side. Hopper vibration/ mixing action leading to segregation of particles (large particle on top & small particle in bottom) Arching/ Bridging/ Rat holing. Prevention: Addition of glidant (talc, colloidal silica) Using induced die feeders Restricting the flow of hopper.

9. PH 101.76 9 7. Weight variation: Tablets will not have uniform weight. Reasons- poor flow of granules. non-uniform particle size distribution of granules. presence of excessive fines. Correction- using proper concentration of lubricants and glidants . by uniform size distribution of granules. decreasing the proportion of fines.

10. PH 101.76 10 8. Hardness variation: Tablets do not have uniform hardness. Reasons- If volume & material varies in die cavity. Distance between punches varies hardness will vary . 9. Punch variation: Differences in punch lengths. Reason: Lower punches of unequal lengths changes die cavity fill volume. Prevention: Using good punches with uniform dimension and die control program.

11. THANK YOU……