The Preparation And Evaluation Of Sustained-Release Alkali/acid External Medicine

As a medicine of wide varieties and applications,external drugs have a unique administration route called transdermal absorption route,which will not be influenced by peptic juice,pH value and gastrointestinal enzymes.External drugs can directly reach the affected part and develop medicine efficacy,which have gained a lot attention.Nowadays,the disadvantages of external drugs remain in lack of biocompatibility,poor adsorbability,low adsorption capacity,slow adsorption rate and so on.Basing on the above situation,this paper investigates two type of external drugs called sustained-release alkali external drug and sustained-release acid external drug.Using different formulations,such as powder spray and paste,accordingly treat various diseases.All these types of medicines have properties of good medicine efficacy,convenient operation and great adsorbability.In the preparation of sustained-release hydrochloric acid paste,activated bentonite and NaCl as the effective components,and the releasing mechanism is the ion exchange between Na+of NaCl and H+of activated bentonite.For the sake of paste stability,the activated index should be 35%,and emulsifier addition should be 0.8 g～1 g per 40 g dispersant.In the preparation of sustained-release alkali paste,the process is calcium hydroxide loaded on the activated bentonite by adsorption.In order to remain stable and obtain a faster transdermal absorption rate,the activated index should be 55%,emulsifier addition should be 1 g per 40 g dispersant,and the absorption rate can reach 128 mmol·m-2·h-1.In the preparation of sustained-release alkali powder spray,the moisture content should be in the range of 7%- 8%for the safety.In the homeostasis of rabbit ear arterial bleeding model,the sustained-release calcium hydroxide powder as the tested subject and the results showed there is no obvious differences between sustained-release calcium hydroxide powder with YunnanBaiyao powder(P>0.05).However,the homeostasis failure rate of sustained-release calcium hydroxide powder was lower than that of YunnanBaiyao powder due to the adsorbability of sustained-release calcium hydroxide powder was much stronger.In the second-degree scalded model,sustained-release calcium hydroxide paste could cure the scalded area in two weeks,while the rabbits of model group were all dead,which indicated that sustained-release calcium hydroxide paste could accelerate the wound healing process and prevent the local inflammatory from becoming systemic inflammatory.The toxicity of calcium hydroxide was lowered by loading on the activated bentonite,and there were two type of medicines which could homeostasis and cure scalded area accordingly through transdermal absorption route.This is a new medicine to cure and prevent surgical diseases.