Study On The Stability And Reasonable Dosage Of Common Pressure-lowering Drugs During Clinical Dossing

Objective: The main purpose of this study is to explore the changes of physical stability of common antihypertensive drugs during hospital pharmacy dispensing process and whether they lead to changes in chemical properties of the drugs by simulating the dispensing environment.By analyzing the dosage form and relevant stability,the reasonable drug dispensing and usage practice was proposed.Contents: This article mainly includes two series of experiments.Drug physical stability is studied by calculating the moisture absorption rate,which is based on the drug weight change before and after humid incubation.The other series of experiments investigated chemical stability of the drugs,mainly by employing HPLC method to test the drug content,dissolution profile and related substances.Results: The experiments indicate that different antihypertensive drugs had various moisture absorption behaviors in the course of drug dispensing.Among the 24 kinds of antihypertensive drugs we studied,four of them had moisture absorption rate higher than30% including telmisartan(mekasone),enalapril maleate,metoprolol tartrate tablets(betaloc 50 mg)and hydrochlorothiazide tablets(Changzhou Pharma).For telmisartan produced by various manufacturers,different moisture absorption percentage and velocity were observed.While no relatively significant change was observed for the drug content,dissolution profile and related substances,determined by HPLC.Conclusion: According to the experiment results,no significant moisture absorption was observed under the current common dispensing conditions with relative humidity at about25% and 50%.A simulated high humidity environment,with a relative humidity at 75%,had greater influence on the physical properties of the antihypertensive drugs,while smaller influence on the chemical properties including drug content,dissolution profile and related substances.Although there are few changes in the chemical properties were observed after the moisture incubation,the drugs were found adhering to the dispensing box,which will affect the total amount of drugs entering human body.Therefore,it isnecessary to keep a relatively low humidity for the hospital pharmacy dispensing process to reduce the drug moisture absorption.Drugs prone to deliquescence,such as telmisartan and nifedipine,which are prone to photodegradation,can be placed in a combined light-shielding and moisture-proof box.