Study On The Dissolution Behavior Of Loratadine In Different PH Medium

Loratadine (LTD), a selective antagonist of histamine receptor1(H1) with higheraffinity to the periphery system, was developed by Schering-Plough Co.Ltd in the U.S. andwidely used clinically in the treatments of allergic disease such as rhinitis, urticaria, titillationand others. However，it was reported that LTD produced some adverse drug reactions,including arrhythmia, sudden cardiac arrest, ventricular fibrillation, supraventriculartachycardia, atrial fibrillation, and so on. Joint pain, secondary agranulocytosis, optic neuritis,abnormal liver function and allergic shock were also demonstrated. Thus, the quality controlof LTD products has been presented in front of the government.In2002, China began to produce oral preparations of LTD. The out put of several kind oftablets, granules, capsules and syrups was increased year by year. In contrast to the amount ofthe products, we were strongly interested in the quality of them. The observation ondissolution behavior of a product could be developed as a prospection parameter in the qualitycontrol system of LTD. In2009，we were powered to initiate an investigation to the qualitystandard of the factories and their products. Dissolution behavior test of LTD from differentfactory is one of the investigation program.RESULT:1.299sets of LTD products collected from41companies were tested. The resultsindicated that all parameters tested to the products were coincide in quality with the standardsfrom their own company, respectively. However, the standards from the41companies weredifferent. They produced LTD in accordance to their own standard. This result indicated thatthe standards are basically correct, but need to be centralized.2. In addition to the excess of standards, some problems existed in the standards areconfused clauses and confused testing conditions in the dissolution determinations.3. We established a one-step testing method to determine the dissolution behavior of asample in different pH medium. By this method we tested the products from33companies. The results indicated that this method could identify one product of a company from another.But this need detailed calculation in the similarity factor f2recommended by the US FDA.4.105standard stripping curves were developed. The curves of the products fromdifferent company were carefully compared with the standard curves. The resultsdemonstrated a12.1%similarity in three pH medium,9.1%similarity in one or two pHmedium and78.8%no similarity.CONCLUSION1.41standards of LTD production from the companies were analyzed. Some problemsare found behind the standards. We suggest that a consolidated standard is needed.2. The method of LTD dissolution testing was established and a series of medium indifferent pH was developed. The dissolution behavior of a standard sample was furtherstudied.3. The dissolution behavior of the products from the companies were tested. The resultsindicated that this method could identify the quality of a product of one company fromanother.