Assetbundle memory leaks

Hi guys! I'm making a game for the ios that has a customization feature. I'm currently using assetbundles and everything seems to be working fine. However everytime I load an asset the memory is not getting released, I'm still really new to this, so I'm probably doing something really basic. Here is the code I'm using to load the asset.

     /// <summary>
     /// Loads asset from Streaming Assets Folder
     /// </summary>
     /// <param name='url'>
     /// Url to load the asset from
     /// </param>
     /// <param name='obj'>
     /// A reference to the object that will recieve the loaded asset
     /// </param>
     public IEnumerator fromStreamingAssets(string AssetName, System.Action<GameObject> obj)
     {        
                 
         // Wait for the Caching system to be ready
         while (!Caching.ready)
             yield return null;
 
         string[] Asset = AssetName.Split('.');
 
         //Get the asset bundles from the given URL (platform dependant)
         string st_Path; 
             
         #if UNITY_IPHONE
             st_Path = "file://" + Application.streamingAssetsPath + "/" + AssetName;
         #endif    
                         
         #if UNITY_ANDROID
             st_Path = Application.streamingAssetsPath + "/" + AssetName;
         #endif        
                         
         #if UNITY_EDITOR || UNITY_STANDALONE_WIN || UNITY_STANDALONE_OSX
             st_Path = "file://" + Application.streamingAssetsPath + "/" + AssetName;
         #endif    
             
         
             //Loads the asset from streaming assets
             WWW www = WWW.LoadFromCacheOrDownload(st_Path,1);
             yield return www;
             AssetBundleRequest request = www.assetBundle.LoadAsync(Asset[0], typeof(GameObject));
             yield return request;
         
             obj((GameObject)request.asset);
             
             //Unload assetbundle and www to clear memory
             www.assetBundle.Unload(false);
             www.Dispose();
         
         
         
 
     }