[Difficulties encountered during formulation of a parenteral dosage form containing a poorly soluble drug].

Poor water solubility and consequently the difficulties in formulating a liquid dosage form is a great concern in pharmaceutical development. The importance of this issue is underlined by the fact that 10-30% of marketed drugs and 60-70% of drugs coming from early development stage have solubility problems. In this paper we summarize the existing solubility enhancing techniques that are applicable in parenteral dosage forms for overcoming the issue. We address the problem of choosing the most adequate solubility enhancing technique and present the considerations that should be kept in mind during formulating the solvent systems. Such questions are for example the possible haemolysing effect of the excipients, pH of the composition and its compatibility with various sterilizing methods. We also focus on the probable technological issues, which may arise in each solubility enhancing method, we present examples for every one of them and where possible the solution to the problem is also proposed.