Solid lipid excipients - matrix agents for sustained drug delivery.

Lipid excipients are attracting interest from drug developers due to their performance, ease of use, versatility and their potential to generate intellectual property through innovation in drug delivery particularly in the case of modifying drug release systems. Many articles have described the use of lipid excipients to develop matrix modified release dosage forms in a range of processing techniques, therefore a comprehensive review is timely to collect together and analyze key information. This review article focuses on the utility of lipid excipients in solid sustained drug delivery systems with emphasis on the efficiency and robustness of these systems with respect to: (i) the choice of the manufacturing process and impact on drug release, (ii) the fundamental drug release mechanisms, (iii) resistance of the drug formulation under physiological conditions and (iv) long-term stability. Understanding the functionality of these versatile excipients in formulation is elementary for the development of highly robust lipid-based sustained release medicines.