Semisolid drugs formulations

Theeuwes, F. and Yum, S.I. (1976). Principles of the design and operation of generic osmotic pumps for the delivery of semisolid or liquid drug formulations. Ann. Biomed. Eng. 4 343-353. 

Ritonavir is a product of Abbott Laboratories Ltd. for the treatment of HIV and is marketed as Norvir , in liquid and semisolid capsule formulations. It received FDA approval for market launch in march 1996, at which time only one polymorphic form of Ritonavir (Form I) was known. Two years later in early 1998 a laboratory responsible for testing the formulated product in the US reported dissolution test failures of the semisolid capsules, and noted that drug product had precipitated out of solution. A new polymorphic form had been discovered that was thermodynamically more stable than the existing form and approximately 5 times less soluble in the formulation. Figure 7. 

Figure 12.19 Drug delivery curves obtained with an implantable osmotic pump [30], Reprinted from F. Theeuwes and S.I. Yum, Principles of the Design and Operation of Generic Osmotic Pumps for the Delivery of Semisolid or Liquid Drug Formulations, Ann. Biomed. Eng. 4, 343, 1976, with permission of Biomedical Engineering Society...

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