Distribution database (recovery pending)
Can you try below  (substitute with appropriate names - publisherdb, publisher, distribution database) :

-- Disable the publication database.
USE [AdventureWorks2012]
EXEC sp_removedbreplication @publicationDB;

**-- Remove the registration of the local Publisher at the Distributor.**
USE master
EXEC sp_dropdistpublisher @publisher;

-- Delete the distribution database.
EXEC sp_dropdistributiondb @distributionDB;

-- Remove the local server as a Distributor.
EXEC sp_dropdistributor;
GO