本研究將防曬劑二苯甲酮-4利用乳化內相膠凝法包覆於天然高分子海藻酸鈉微膠囊內，以降低化學性防曬劑直接接觸皮膚所造成的刺激及過敏反應。探討微膠囊製程中不同濃度的高分子殼材SA、乳化劑Span80及芯材物質BP-4，對於微膠囊之平均粒徑、比表面積、粒徑分布、包埋率及負載率之影響，評估防曬劑自微膠囊中釋放之動力模式，並比較經海藻酸鈉包覆後之BP-4的SPF值及光穩定性。實驗結果顯示，微膠囊平均粒徑約100~500μm，其平均粒徑、比表面積及粒徑分佈均取決於乳化微胞的大小、乳化穩定性及高分子殼材交連程度；而包埋率、負載率及釋放速率則受平均粒徑的影響。因此藉由調整高分子殼材及乳化劑濃度可改變微膠囊之粒徑，進而控制其釋放速率。BP-4微膠囊在pH 5.0之磷酸緩衝溶液中完全釋放之時間約為90分鐘，其釋放行為符合一級動力模式。包覆後的BP-4微膠囊SPF值及對於紫外線的穩定性相較於未包覆之BP-4有明顯提高，SPF值隨殼材海藻酸鈉濃度的增加而提高，其光分解速率為一級動力模式。 The purpose of this study was the preparation and investigation of sunscreen containing polymeric microcapsules. Different microcapsules were obtained by emulsification/internal gelation. First the sunscreen Benzophenone-4 (BP-4)/sodium alginate (SA) solution was mixed with CaCO3 solution, then the solution was added into liquid paraffin of span80 to get W/O type reversal micelles emulsion. The glacial acetic acid was dropped into emulsion to initiate polyelectrolyte gelation between Ca2＋and carboxylate of SA to form microcapsules. The parameters included amount of span80, sodium alginate and BP-4 were investigated, for discussing the average particle size, specific surface area, particle size distribution, encapsulation efficiency and loading capacity of the microcapsules.
The structure and morphology of microcapsules depended mainly on Span80 and SA concentration. BP-4 released and photodegradation mechanism followed very well with first order model. And the SPF value was promoted obviously after encapsulation.
