物料性質(zhì)對中藥實驗室霧干燥機粘壁性的影響

 中藥提取物的性質(zhì)與粘壁性的關(guān)系
吸濕性  中藥提取物的吸濕性是影響噴霧干燥的主要問題，中藥浸膏粉吸濕后導致粉體粘性增強、分散性降低。因此，實驗室霧干燥機在噴霧干燥過程中，粉體的吸濕性是造成粘壁現(xiàn)象或結(jié)成塊狀的主要原因。 相對密度  提取液的相對密度對噴霧干燥的影響較為顯著。提取液經(jīng)濃縮后相對密度一般以控制在1．05～1．15為宜。但不同種類的中藥提取液，其相對密度的適宜范圍也不同。如冰黃五苓散提取液適宜的相對密度為1．18一1．22，實驗室霧干燥機在進風溫度、進風量不變的情況下，隨著密度的增加，粘壁情況減輕，得粉率提高；但隨著提取液密度的增加，導致藥液流動性變差，易出現(xiàn)粘壁現(xiàn)象，并可引起噴頭堵塞等問題。 
軟化點  中藥浸膏軟化點低于進風溫度是產(chǎn)生粘壁現(xiàn)象的主要原因。杜松等H o研究發(fā)現(xiàn)：中藥浸膏實驗室霧干燥機干燥過程存在一個“軟化點”溫度，超過這個溫度，物料就容易塌陷粘壁。水提在噴霧干燥時粘壁情況不嚴重，而水提液經(jīng)醇沉除雜后的藥液及中藥的高濃度乙醇提取液在噴霧干燥過程中易產(chǎn)生較為嚴重的粘壁現(xiàn)象，這是由于水提取液中含有淀粉等高玻璃化轉(zhuǎn)變溫度Tg物質(zhì)，經(jīng)醇沉后淀粉被除去，而高濃度乙醇提取液中淀粉含量極低，使得提取物的Tg低于噴霧干燥時的溫度，則出現(xiàn)干燥物塌陷、變軟，導致粘壁現(xiàn)象發(fā)生。李智等將甘草用不同質(zhì)量分數(shù)(300，400，500，600，700 g／L)的乙醇溶液進行提取，然后將各提取液分別進行噴霧干燥，結(jié)果發(fā)現(xiàn)：使用600 g／L以上乙醇的提取物，在干燥時粘壁現(xiàn)象較為嚴重。另外，藥液在噴霧干燥前須過篩，防止粗?；烊?，阻塞噴嘴；過濾后的藥液，在70一90℃保溫，這樣利于藥液流動，能減少粘壁情況。
輔料對防粘壁的作用  鑒于以上中藥提取物本身的性質(zhì)、特點及噴霧干燥時粘壁的情況，需要對中藥提取物進行改性．常采用加入輔料的方法改變中藥提取液的特性，以改善粘壁的情況。

英文版：

The effect of material properties on the adherence of the traditional Chinese medicine laboratory fog dryer

The relationship between the properties of the extract of Chinese medicine and the adherence
The moisture absorption of the extract of the hygroscopic Chinese medicine is the main problem affecting the spray drying. The moisture absorption of the extract powder of traditional Chinese medicine leads to the enhancement of the viscosity of the powder and the decrease of the dispersibility. Therefore, in the process of spray drying, the moisture absorption of the powder is the main cause of the phenomenon of wall sticking or the formation of lump. The relative density of the relative density extract has a significant effect on the spray drying. The relative density of the extracted liquid after concentration is generally controlled from 1.05 to 1.15. But the suitable range of relative density of different kinds of traditional Chinese medicine extracts is different. Ice yellow Wuling powder extracting liquid suitable for relative density of 1.18 to 1.22, the inlet air temperature, air flow is constant, with the increase of density, reduce the wall sticking, powder rate to increase; but with the increasing density of liquid extract, lead to poor liquidity and prone to sticking to the wall, and can cause problems such as nozzle clogging.
The softening point of the softening point of the Chinese medicine extract is lower than the air inlet temperature, which is the main cause of the wall sticking phenomenon. Du Song and other H o studies found that there is a "softening point" temperature in the drying process of the extract of Chinese medicine, which can easily collapse to the wall of the wall. The water in the spray drying when sticking to the wall, the case is not serious, and the water extract by ethanol precipitation of high concentration of ethanol in liquid impurities and traditional Chinese medicine extraction is a serious phenomenon of sticking to the wall is easy to produce in the spray drying process of liquid, which is due to the water extraction of starch containing high glass transition temperature Tg material liquid. After the starch was removed by ethanol precipitation, and high concentration of ethanol extraction liquid starch content is very low, the extract of Tg is lower than the temperature of spray drying, there is dry collapse, soft, lead to the occurrence of the phenomenon of adhering wall. Li Zhi and other licorice extracts were extracted with different mass fraction (300400500600700 g / L) of ethanol solution. Then the extracts were spray dried separay. It was found that the extract with 600 g / L ethanol was more serious when drying. In addition, the liquid should be sifted before spray drying to prevent coarse particles from mixing and obstruct the nozzle. After filtration, the best solution should be kept at 70 to 90 degrees, so that it can help the liquid flow and reduce the sticky wall.
The effect of excipients on the anti sticking wall is due to the nature and characteristics of the above extracts and the situation of sticky wall when spray drying. It is necessary to modify the extract of traditional Chinese medicine. The method of adding excipients is often used to change the characteristics of the extract of traditional Chinese medicine, so as to improve the condition of sticky wall.