Changing a drug to match a drug delivery technology - Analytical Methods & Tools for Lyophilization

Changing a drug to match a drug delivery technology
08/10/2006
By Gregory Roumeliotis
DrugResearcher.com
When selecting a pharmaceutical formulation, the conventional wisdom has been to manipulate a drug delivery platform to make it compatible with a drug?s properties, yet the opposite approach may have several benefits if enough thought is put into it early in the development process, according to Brookwood?s chief scientific officer.
From drug class and route of administration to the dose and duration of delivery, there are several considerations that may affect not just a drug's therapeutic success but also its manufacturing process, Tim Tice said in his speech at the Controlled Release Society's annual meeting in Vienna.
The formulation can have an impact on materials sourcing, the cost of goods, the drug's stability, regulatory compliance and several production issues, whether terminal sterilisation is used instead of aseptic manufacturing for example.
It is therefore important to factor in scale-up, development times, the available technical know-how and the reliability of a new drug delivery technology in formulation design.
But deciding on a drug delivery system is of course not just based on the manufacturing process because development is driven by clinical targets and the nature of the molecule is crucial.
So for oral routes of administration it is typically small molecules used, not peptides or biologics, and the same is the case with transdermal systems whereas parenteral delivery allows the use of biologics, and there have been exciting developments lately in the field of pulmonary delivery where peptides are used.
Traditionally, when bringing a delivery technology and a drug together, companies have turned to the delivery system to make it fit the drug, not the other way around.
?There is often a lack of communication between R&D staff and formulation scientists which leads to a focus on the drug delivery system when the drug is pretty much developed,? Tice told In-PharmaTechnologist.com.
?One should also be thinking about how to optimise a drug to match a drug delivery technology and facilitate manufacturing.?
As an example Tice cited the use of proteins in microparticles for parenteral administration.
A lower peptide solubility can lead to higher loading, smaller microparticles and longer duration of therapeutic action.
Among other techniques, Brookwood uses a continuous microencapsulation process whereby a drug, polymer and polymer solvent dispersion are added to a mechanically agitated water/surfactant mixture to form an emulsion of microdroplets which is then extracted with water to remove solvent and form hardened microcapsules or microspheres for collection by centrifugation, filtration or the like.
The company recently teamed up with Genzyme Pharmaceuticals to provide peptide delivery solutions, not promoting a specific technology, but instead optimising peptide physical and chemical properties early on in drug development, so as to match a peptide with the properties of microparticles, implants and other drug delivery formulations required for optimal drug delivery.
As more pharmaceutical companies focus on drug delivery not just as part of a drug's life cycle management but as an integral component of drug development, optimising a drug for formulation becomes crucial, Tice concluded.
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