Evaluation of micropraticulate DDS and its applications
- 1. Novel drug delivery systems Evaluation of microparticulate DDS and its application By- Aatish jayale 1 Dr. Rajendra Gode Institute of pharmacy
- 2. Classification of evaluation of micropraticulate DDS 2 Physiochemical evaluation In vitro method In vivo method In vitro/in vivo corelationship 1. Particle size and shape 2. Density determination 1. Beaker method 2. Dissolution method 1. Animal model 2. Buccal absorbtion test
- 3. 3 3. Isoelectric point 4. Angel of contact 5. Electron spectroscopy for chemical analysis 6. Fourier Transform infrared Spectroscopy 7. Drug entrapment efficiency 8. Percentage yield 9. Swelling index
- 4. A. Physiochemical evaluation 4 Particle size can be determined by optical microscopy with the help of calibrated eyepiece micrometer. The size of around 100 microspheres is measured and their average particle size is calculated D mean = E n d/E n n = number of microspheres , d= Mean size 1. Particle size and shape
- 5. 2 2. Density determination The density of microspheres can be measured by using a multi volume pycnometer.
- 6. 5 1. Accurately weighed sample in a cup is placed into the multi volume pycnometer. 2. Helium is introduced at a constant pressure in the chamber and allowed to expand. 3.This expansion results in decrease in pressure within the chamber. 4.Two consecutive readings of reduction in pressure at different initial pressure are noted. 5. From two pressure readings the volume and density of microsphere is determined.
- 7. Multi volume phycometer 3. Isoelectric point the point at which the net charge on a molecule is zero. 6
- 8. 1.The isoelectric point can be measured by using micro electrophoresis apparatus by measuring electrophoretic mobility of microspheres. 2.The mean velocity at different pH value from 3-10 is calculated by measuring the time of particle movement over a distance of 1 nm. 7
- 9. Electrophoresis appratus 4. Angle of contact The angle of repose of microspheres, which measures the resistance to particle flow 8
- 10. 9
- 11. 5. Electron spectroscopy for chemical analysis The surface chemistry of microspheres can be determined by using electron spectroscopy for chemical analysis The spectra obtained using ESCA can be used to determine the surface degradation of biodegradable microspheres. 10
- 12. 6. Fourier Transform infrared Spectroscopy Drug polymer interaction and degradation of microspheres can be assessed by FTIR. 11
- 13. 12 7. Drug entrapment efficiency Weighed amount of microsphere are taken and crushed. Then dissolved in buffer solution with the help of stirrer and filtered. The filtrate is assayed by UV spectrophotometer at particular wavelength by using calibration curve.
- 14. 13 8. Percentage yield It is calculated as the weight of microspheres obtained from each batch divided by total weight of drug and polymer used to prepare that batch multiplied by 100.
- 15. 9. Swelling index 14 It is determined by measuring the extent of swelling of microspheres in a particular solvent. The equilibrium swelling degree of microspheres is determined by swelling of 5 mg of dried microspheres poured in 5 ml of buffer solution overnight in a measuring cylinder.
- 16. 15 B. In-vitro method 1. Beaker method In this method dosage form is made to adhere at the bottom of beaker containing the medium and stirred uniformly using overhead stirrer. Volume of the medium used in the literature for the studies varies from 50-500 ml and the stirrer speed from 60-300rpm,
- 17. Overhead stirrer 2. Dissolution test apparatus Standard USP or BP dissolution apparatus have been used to study in vitro release profiles using both rotating elements Paddle and basket. 16
- 18. Dissolution medium used for the study varies from 100-500 ml and speed of rotation from 50- 100rpm. Dissolution apparatus method 17
- 19. C. In vivo method 18 1. Animal models It is used mainly for the screening of series of compounds, investigating the mechanisms and evaluating a set of formulations. Animal model such as dogs, rats, pigs and sheep etc. are reported. Generally the procedure involves anesthetizing the animal followed by administration of dosage form, withdrawing blood at different time intervals and analyzing
- 20. 19 2. Buccal absorption test It is most suitable and reliable method for measuring the extent of drug loss from human oral cavity for single and multi-component mixtures of drugs. The test is carried to measure the kinetics of the drug absorption by swirling a 25 ml sample of the test solution for 15 min by human volunteers followed by the expulsion of the solution.
- 21. 20 D . In vitro/in vivo correlation Correlations between in vitro dissolution rates and the rate and extent of availability as determined by blood concentration and or urinary excretion of drug or metabolites . Such correlations allow one to develop product specifications with availability.
- 22. Application of Microencapsulation 21 1. Microencapsulation can be used to formulate various sustained controlled release dosage forms by modifying or delaying release of encapsulated active agents or core materials. 2. Microencapsulation can also be employed to formulate enteric-coated dosage forms, so that the drugs will be selectively absorbed in the intestine rather than the stomach.
- 23. 22 3. Gastric irritant drugs are being microencapsulated to reduce the chances of gastric irritation. 4. The taste of bitter drug candidates can be masked by employing microencapsulation techniques
- 24. 23 5. Through microencapsulation, liquids and gases can be changed into solid particles in the form of microcapsules. 6. Microencapsulation can employed to aid in the addition of oily medicines to tableted dosage forms to overcome the problems of tacky granulations and in direct compression.
- 25. 7. Microencapsulation can be used to decrease the volatility. A microencapsulated volatile substance can be stored for longer times without any substantial evaporation. 24
- 26. Thank you !