Quantitative Control On Preparation Of Microcapsules By Spray Drying

Microencapsulation is a new technique to wrap solid,liquid or gaseous materials in tiny half permeability or sealed materials which can be natural or synthetic polymer cyst materials.This technique can make the release of core contents with controllable rate in specific conditions.Three drugs with entirely different characteristics were chosen as model drugs. The prescriptions and artwork condition of microcapsules were studied respectively, which are significant for making microcapsules with spray drying technique in theory; effect factors were distinguished into artwork factors and prescription factors,effect factors and solve way of microencapsulation were found by studying. Selection of drugs and capsule wall materials and their concentrations,core–material ratios,Selection and dosages of adjuvants were included in prescription factors,and Into wind temperature,spray pressure,feeding rate were included in artwork factors. Quality specifications of microcapsule were formulated.The optimal artwork factors and prescription factors of spray drying were found by measuring envelopment,diameter distribution,microcapsule appearance etc.Stability also was studied,and the result showed that detected samples was consistent with quality specifications.Metformin hydrochloride was chosen as the model drug insoluble in alcohol in the experiment of spray drying to be made into slow-released preparations. General range of artwork factors and prescription factors were studied by single-factor test,and the optimal condition were definited by orthogonal experiment.The optimal parameters were as followed: Eudragit L100 dosage was 5%, the best ratio of core and polymer material was 1:3; elasticizer dosage was 5%,;antitack agent dosage was 20%; temperature was at 145℃;spray pressure was 0.30Mpa;feeding rate was 10ml/min.The metformin hydrochloride microcapsule prepared by the established method were with satisfying ER and slow release,and uniformity particle diameter and good stability.Roxithromycin was chosen as the model drug soluble in alcohol in the experiment of spray drying ,and bitter taste masking effect was added as a new quality specifications. General range of artwork factors and prescription factors were studied by single-factor test,and the optimal condition were definited by orthogonal experiment.The optimal parameters were as followed: Eudragit L100 dosage was 6%, the best ratio of core and polymer material was 1:4; elasticizer dosage was 5%,;antitack agent dosage was 20%; temperature was at 170℃;spray pressure was 0.40Mpa;feeding rate was 15 ml/min. ER of the roxithromycin microcapsules could reach up to no less than95% and with good bitter taste masking effect.Vitamin A was chosen as the model drug in the experiment of solidification of liquid drugs to boost the stability to make it easy for storage and application. Artwork factors and prescription factors were studied such as quality of core material,concentration of wall material,speed of High-speed shear and so on.. The optimal condition were definited by orthogonal experiment,the result was as followed: gelatin dosage was 6%, the best ratio of core and polymer material was 0.55:1; oil-water phase ratios was 20%; temperature was at 175℃;spray pressure was 0.26Mpa; mixing time was 35 min,mixing speed was 4800 r/min. Vitamin A microcapsules prepared by spay drying was with good stability and solidification effect.Good effect of microcapsules of three different types preprated by spay drying was showed in the experiments,which achieved the desired expectations.