The objective of the study is to develop and evaluate a generic topical formulation containing isotretinoin and to compare with a brand name product. A gel formulation was developed with hydroxypropylcellulose and characterized by means of appearance, drug content, pH, rheological properties and in vitro drug release profiles. All result was evaluated depending on the requirements of national and international authorities and also literature based knowledge. For this aim, Q1 (qualitative), Q2 (quantitative) and Q3 (microstructure) similarity to the brand name product should be achieved. As a result, a generic gel formulation which can be an alternative for markets was developed and found similar to the brand name product. A generic topical gel formulation of isotretinoin with hydroxypropylcellulose was successfully produced for drug markets. This study revealed all stages and important parameters of a semi-solid generic product development.