Evaluating the effect of spherical crystallization of acetylsalicylic acid crystal and crystal agglomeration of Manihotesculenta starch on direct compression tablet properties

Spherical crystallization and crystal agglomeration have been used to optimize compact crystals and functional properties of powders. The aim of this work is to evaluate the effect of spherical crystallization of acetylsalicylic acid crystals and crystal agglomeration of Manihotesculenta starch on direct compression tablet. Typical spherical crystallization using three solvent system of water–ethanol-carbon tetrachloride was used to produce spherical acetylsalicylic acid. Salting-out agglomeration of gelling in water and salting in ethanol was used to produce starch-xerogel from Manihotesculenta starch. The modified products were qualified using FT-IR analysis. The analysis results showed that modification did not alter chemical nature of the products. Acetylsalicylic acid tablets were formulated using spherical-crystallizedacetylsalicylic acid with 5 and 10% w/w starch-xerogel respectively, and using acetylsalicylic acid with 5 and 10% w/w of starch, and microcrystalline cellulose respectively. The physicochemical properties of the tablets were evaluated. Astatistical 23 factorial design of the tablet properties at 5% level of significance showed that the effects of the variables are different. Theacetylsalicylic acid tablets formulated from direct compression of spherical-crystallizedacetylsalicylic acid with 5 % w/w starch-xerogel produced quality tablets comparable to standard tablets from direct compression of acetylsalicylic acid with10 % w/w microcrystalline cellulose. Spherical crystallization and crystal agglomeration optimized the compact crystals of starch and acetylsalicylic acid, and improved direct compression properties of the crystals, and drug release from tablet.

Application of the liquid bridges theory to find the melt menisci shape when growing cylindrical crystals

A vertical liquid bridge of small volume between a conical shaper and a convex crystallization front was investigated. Two variants of the front crystallization shape selection are considered: a conical and a spherical fronts. A variational statement of the original problem is given. As the boundary conditions we used the condition of engagement at the edge of the shaper and a given growth angle at the crystallization front. The Bond number was assumed to be small, and to find a solution of the problem the asymptotic approach was applied. The calculations are carried out for small diameter cylindrical sapphire crystals, grown from the melt by the Stepanov method. The results of the menisci shapes calculations are presented. The comparison of the results of calculations for conical and spherical crystallization fronts is carried out.

Spherical Crystallization: A Tool to Improve the Physicochemical Properties of APIs

A greater challenge in solid dosage formulation is the development of spherical agglomerates which increases the solubility and bioavailability of the drug. Spherical crystallization is “An agglomeration process that transforms crystals directly into compact spherical forms during the crystallization process.” Spherical crystallization is the novel agglomeration technique that can transform directly the fine crystals produced in the crystallization process into a spherical shape. Direct Compression of powders is simple and easy way of making tablets. In direct compression of Good Compressibility and flowability plays a major role. Spherical crystallization methods are very useful methods in which the drug crystals are modified using different solvents to directly compressible agglomerates. which cost effective and time saving. The different Techniques discussed are Crystallization method, Solvent crystallization method, Quasi- emulsion diffusion method, Ammonia Diffusion method, neutralization method, and solvent agglomeration technique. This article gives a detailed and comprehensive review about different techniques, its advantages, mechanism and application of Spherical agglomeration Technique along with its Evaluation and Characterization methods.