Formulation and Evaluation of Sustained Release Ambroxol Hydrochloride Microsphere Enriched Syrup

The main objective of the present work is to formulate taste masked microspheres enriched syrup of ambroxol hydrochloride by an o/w emulsion solvent evaporation method. Such taste-masked formulations have been found to improve the quality of treatment in patients. Ambroxol hydrochloride microspheres help to protect the gastric mucous membrane from drug irritation and to mask its taste. The prepared microspheres enriched syrup were evaluated for particle size, effect of drug and polymer ration and volume of dispersed phase, percentage yield, incorporation efficiency, pH, viscosity, scanning electron microscopy and in vitro drug release. The microspheres produced exhibited good encapsulation efficiencies and rheological properties. The maximum percentage yield of microsphere is around 85.31% and viscosity is 31000 cps. The mean diameters of microspheres were found in range between 4μm to 14μm. The results of optimized formulations showed a narrow size distribution and smooth surface. In-vitro release showed 72.3% drug release after nine hours. Key word: Microspheres enriched syrup, Viscosity, SEM. INTRODUCTION Ambroxol is a metabolite of bromohexine which possess mucokinetic and secreteolytic properties. It is used in the treatment of respiratorytract disorders such as chronic bronchitis and management of cough. Adverse effects produced suchas gastrointestinal disorder, headache, dizziness, sweating, rhinorrhoea, lacrymation and allergic reactions. Due to short biological half-life (4-6 hr), frequent daily dosing (2-3 times) of Ambroxol hydrochloride is required. Therefore its formulation inSR microspheres is advantages.The simplest and least expensive way tocontrol the release is to dispense it with in an inertpolymeric matrix. Bitter after taste of many drugs which are orallyadministered often contributes to patient noncompliancein taking medicines. Unfortunately, majority of the drugshave a natural bitter taste that can create a burning feelingin the throat or in the mouth; many active ingredientssuch as antibiotics possess a strong unpleasant taste.Administration of bitter drugs orally with acceptablelevel of palatability is important in case of pediatric andgeriatric patients. Thus elimination or reduction of bitternessis an important parameter of product evaluation inoral pharmaceutical formulations. Proven methods forbitterness reductions have resulted in improved palatabilityof oral pharmaceutical formulations. Various techniqueshave been developed to improve taste, such as polymeric coating technique, complexation using cyclodextrinsand ion-exchange resin, using known coating orencapsulation processes with very limited success. Ambroxol syrup is marketed in many countries worldwide for pain relief for sore throat. The local anaesthetic action of ambroxol, a sodium channel blocker, might be effective to relieve symptoms due to inflammation. MATERIALS AND METHODS MATERIALS Ambroxol hydrochloride was generously supplied as a gift sampleby Alembic Ltd. Vadodara, India. Ethyl cellulose and PVP was obtained from Essex, UK, monobasic sodium phosphate and dibasicsodium phosphate Sigma Aldrich, Germany. METHOD Preparation of microspheres The microspheres containing drugs were prepared by quasi emulsion solvent diffusion method using different drug and polymer ratio as shown in Table 1. The inner phase, ethocel and drug were dissolved in dichloromethane, ultra sonication for 10 min. The outer phase prepared by dissolving PVA in distilled water at 40oC for 5 min. The inner phase is cooled then poured drop wise into outer phase. The resultant mixture was stirred by magnetic stirrer for 120 min at 25oC, and filtered to separate the microspheres. The microspheres were dried in an air heated oven at 40 °C, and weighed to determine the yield. Preparation of microsphere enriched syrup Weight of microspheres added in the syrup formulation is equivalent to 30 mg of ambroxol hydrochloride, calculated on the basis of assay value. Microspheres prepared above were mixed separately with all the ingredients shownin Table 2. Buffers like monobasic sodiumphosphate and dibasic sodium phosphate were addedto adjust the formulation to pH 7. A sweetening agent, aspartame and vanilla added as a flavoring agent to all the formulation to improve the palatability. Jaya raja Kumar/J. Pharm. Sci. & Res. Vol. 6(8), 2014, 282-284