Formulating Biologics

Dear fellow student, this is Dr. Lee again. And we’re going to work on part three of the biotechnology mini-series. The title for this talk is formulation of biotechnology products. And the materials are taken from these 2 references. Learning objectives, we’re going to discuss the formulation approaches to improve the bioavailability of biotechnology products. To explain the effect of glycosylation and pegylation on the pharmacokinetics of biotechnology products And to explain the targeted delivery of biotechnology product and the therapeutic benefit. And we are going to discuss the additives that are used in the parenteral formulation of biotechnology products And to describe the microbiological considerations of quality control or biotechnology products. And lastly to describe the ascetic conditions for the manufacturing of biotechnology products.

First of all, let’s look at all possible route of drug administration. Parenteral route include IV, SC, IM, IP and others such as intrathecal. Non parenteral route includes PO that is oral. Nasal, transdermal, and others such as intraocular. And given the choice PO or the oral nutrition will be the most desirable route. However, following oral administration of biologics, you’re not going to fare very well. Because oral administration results in very low oral bioavailability for the following reasons. First, proteins degrade by peptidase and a protease in the GI tract. Secondly, large molecules have poor permeability of the GI membranes, and the diffusion coefficient decreases with increasing molecular size.

Now here oral vaccine is probably the only exceptional because the target cells are lymphocyte and only a small fraction of the dose is needed to reach the target site for immune response such as polio vaccine. Now parenteral administration when given intravenously it doesn’t fare very well either because IV injection is subject to immunogenic response and then the drug is rapidly cleared. IM is not as rapidly cleared as IV, but it is subjective metabolic degradation at the site of injection. And that leaves SC the ideal route.

In addition, receptor binding is a part of elimination process. It’s not merely to elicit from a logical response as in the case of small molecules So overall, parental administration exhibits poor uptake and quick circulatory turnover.