Higuchi plots for tablet dissolution

Introduction to Higuchi plots for tablet dissolution
Dissolution, Dissolution Models, Higuchi Plot
Presented by
Mohamed Omar Mahmoud
Department of Pharmaceutics

1. 1 A seminar as a part of curricular requirement for I year M.Pharm I semester Mohamed Omar Mahmoud (Reg. No.20L01S0310) Dept. Of Pharmaceutics Under the guidance of Dr. Pavan Kumar Chintamaneni M.Pharm, Ph.D. Associate Professor & Head Department of Pharmaceutics Higuchi plots for tablet dissolution

2. 2 INTRODUCTION DISSOLUTION DISSOLUTION MODELS HIGUCHI PLOT REFERENCES CONTENT

3. 3 Drug dissolution is important test used to evaluate release of solid and semisolid dosage forms. This test also quantifies the amount and extent of drug release from dosage forms. The values that are obtained from the dissolution study can be quantitatively analyzed by using different mathematical formulae, Because qualitative and quantitative changes in a formulation may alter release of drug and in- vivo performance . INTRODUCTION

4. 4 Thus mathematical models can be developed. This development requires the comprehension of all phenomena affecting drug release kinetics and this has a very important value in the formulation optimization. Once a suitable function has been selected, the dissolution profiles are evaluated depending on the derived model parameters.

5. 5 Def:- Dissolution rate may be defined as, "amount of drug substance that goes in the solution per unit time under standard conditions of liquid/solid interface, temperature and solvent composition .“ The release from the tablet is slow. The effectiveness of a tablet in releasing the drug for absorption depends on two stages initial stage involve breaking of tablet into granules (disintegration). Sometime, these granules further break to yeild fine particle ( de-aggregation ) the next step involves the releasing of the drug in to solution (dissolution) DISSOLUTION

6. 6 The Process involved in Dissolution of Tablet and Capsule

7. 7 Dissolution profile : It is a graphical representation [in term of concentration vs time ] of complete release of A.P.I. from a dosage form in an appropriate selected dissolution medium. i.e. in short it is a measure of release of A.P.I. from dosage form with respect to time IT'S NEED: To develop in vitro- in vivo correlation which can help to reduce costs, speed up product development. pharmacological dosage form. To stabilize final dissolution specification for DISSOLUTION MODELS

8. 8 Dissolution profile of an A.P.I. reflects its release pattem under the selected condition sets. i.e. either sustained release or immediate release of the formulated formulas. For optimizing the dosage formula by comparing the dissolution profiles of various formulas of the same A.P.I FDA has placed more emphasis on dissolution profile comparison in the field of post approval changes. The most important application of the dissolution profile is that by knowing the dissolution profile of particular product of the BRAND LEADER, we can make appropriate necessary change in our formulation to achieve the same profile of the BRAND LEADER . Importance of dissolution profile Comparison :

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11. 11 Higuchi model (Diffusion matrix formulation) This is given by Higuchi. Q = K√T Where Q is the amount of drug released in time't ' per unit area K is higuchi constant T is time in hr Plot : The data obtained is to be plotted as cumulative percentage drug release versus Square root of time. Application: modified release pharmaceutical dosage forms, transdermal systems and matrix tablets with water soluble drugs. Higuchi plots for tablet dissolution

12. 12 Higuchi model

13. 13 Higuchi model

14. 14 The first example of a mathematical model aimed to describe drug r elease from a matrix system was proposed by Higuchi in 1963 this model is applicable to study the release of water soluble and low soluble drug incorporated in semisolid and solid matrices Model expression is given by the equation: Q = A [D (2C - Cs) Cs t] 1/2 Where Q is the amount of drug released in time t per unit area A, C is the drug initial concentration, Cs is the drug solubility in the media and D is the diffusivity of the drug molecules (diffusion coefficient) in the matrix.

15. 15 Simplified Higuchi model describes the release of drugs from insoluble matrix as a square root of time dependent process based on Fickian diffusion Equation. Q = KH t1/ 2 Higuchi model

16. 16 The major benefits of this equation include the possibility to: facilitate device optimization . (ii) to better understand the underlying drug release mechanisms. The equation can also be applied to other types of drug delivery systems, like controlled release transdermal patches or films for oral controlled drug delivery . The Higuchi and zero order models are used to describe the limits for transport and drug release. Higuchi model

17. 17 Higuchi plots to ascertain release kinetics of Diclofenac Sodium samples. In Vitro Dissolution Study and Assay of Diclofenac Sodium from Marketed Solid Dosage form in Bangladesh September 2018

18. 18 The present study was an attempt to formulate and evaluate enteric coated tablets for azithromycin dihydrate to reduce the Gastrointestinal tract side effects.Three formulations of Core tablets were prepared and one who shows rapid disintegration (below three minutes) was selected for enteric coating 

19. 19  The objective of the present investigation was to develop a bilayer-floating tablet (BFT) for Indomethacin using direct compression technology. Bilayer tablets were punched using optimized solid dispersion, 

20. 20 1. Jambhekar S, Breen PJ (2009) Basic pharmacokinetics. Pharmaceutical Press, London, UK, p: 159. 2. Brahmankar DM, Jaiswal SB (2009) Biopharmaceutics and pharmacokinetics: A trea Technologies tise . Vallabh Publications, India, p: 20. 3. United States of Patent Application (2006). 4. Thakkar VT, Shah PA, Soni TG, Parmar MY, Gohel MC, et al. (2009) Goodness-of-fit model-dependent approach for release kinetics of levofloxacin hemihydrates floating tablet. Dissolution Technologies 16: 35-39. REFERENCES

21. 21 THANK YOU