Disclosed are methods of preparing a pharmaceutical composition that is a mucoadhesive film by: (i) combining a film-forming mucoadhesive polymer, apomorphine particles containing an acid addition salt of apomorphine, and a solvent to form a mixture; and (ii) pouring the mixture onto a surface and evaporating some of the solvent to form an intermediate film including the apomorphine particles; where the method further includes contacting or impregnating the intermediate film or mixture with a pH neutralizing agent to produce the mucoadhesive film containing the apomorphine particles and the pH neutralizing agent.