Formulation and Evaluation of Silymarin Microcrystals by In- Situ Micronization Technique

Abstract

Silymarin (SM) is a plant extract obtained from Silybum marianum( milk thistle) . It is class II type drug according to  Biopharmaceutics Classification System with low bioavailability due to its low solubility.

Micro/nanonization during crystallization, surface modification and crystal structure modification may improve the dissolution rate of poorly water-soluble drugs.

The aim of this study was to increase the water solubility and dissolution rate of SM by in-situ micronization using solvent change either by stirring or ultrasonic method. Stabilizers like Gelatin, PVP-K30, HPMC15, Pulullan were used to stabilize the prepared ultrafine crystals. Effect of type and concentration of hydrophilic polymer, solvent: antisolvent volume ratio and the effect of ultrasonic irradiation were studied. The prepared  microcrystals were evaluated for their %yield,  water solubility, crystals structure by XRD,DSC, and SEM. Particle size and  dissolution rate were also tested . Silymarin microcrystals prepared by ultrasonic method and stabilized by 0.1%gelatin using 1:2 solvent: anti-solvent volume ratio showed the best results with particle size reduction from mean diameter of 1.5µm (untrated silymarin) to 0.43µm with uniform morphology and enhanced solubility and  dissolution.

Received: 6 / 8 /2018

Accepted: 15 /9/2018