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Asking the hard questions on pill-popping and polymers

Thursday, 5 November 2015

Jill and Jasper
Recent PhD graduates Jill Assawasuwannakit and Jasper Chiu.

Otago School of Pharmacy PhD graduates Piyanan (Jill) Assawasuwannakit and Jasper Chiu both kept improved patient outcomes at top of mind during their long years of research.
Beyond that, the two took radically different paths. Dr Assawasuwannakit explored that difficult territory where medicine prescribing meets patient behaviour, while Dr Chiu focused on the behaviour of nanoparticles.
Dr Assawasuwannakit says even when patients receive interventions encouraging optimal use, some slip back into their original poor adherence behaviour in the longer term.
“If it’s hard to maintain and improve adherence,” she says, “why not look at it the other way around? Find their adherence pattern – for example, they may forget a tablet occasionally – and provide a drug that forgives that.”
Dr Assawasuwannakit initially investigated adherence patterns among patients recruited from a local pharmacy. She ran a feasibility study of the use of medication event monitoring system (MEMS) devices – where the medication bottle has an embedded microchip in the cap, which can record exactly when the bottle is opened.
Dr Assawasuwannakit then quantified drug mechanisms, ultimately developing a formula that quantifies “relative forgiveness” – ie, the numerical relationship between therapeutic success from perfect, versus imperfect, adherence.
Applying this to warfarin, atorvastatin and omeprazole and using her MEMS data, she concluded the formula is generalisable and can be used at the individual patient level. It also suggests prescribers who know a patient’s adherence is imperfect can consider a more forgiving treatment for them.
A Thai national who earned her BPharm in Bangkok, Dr Assawasuwannakit spent six years at the school and is now back home as a postdoctoral fellow in tropical diseases.

Dr Chiu, originally from Malaysia, gained his bachelor’s at Otago in 2007, then worked in retail pharmacy for almost three years, before returning to the school to continue work he and other students had begun earlier on polymeric nanoparticles.
“I took a great liking to it and wanted to dig more into it,” he says. Internationally, experimentation in this field is in its infancy and safety issues remain. But Dr Chiu says it has great potential for improving oral bioavailability of therapeutic ingredients, thereby reducing the need for high doses with sometimes significant side effects.
Dr Chiu created poly (ethyl cyanoacrylate), or PECA, nanoparticles tagged with oligoarginines for enhanced cellular absorption, tested the particles in cells in the lab and derived a mathematical model for the nanoparticles’ behaviour.
He says his study finds the 80 per cent absorption increase reported by overseas researchers is almost impossible to achieve, as cells would come into contact only with a small proportion of the nanoparticles in the particle suspension. He concludes PECA is unsuitable and “too leaky” to be used as a carrier for therapeutic ingredients.
In July, Dr Chiu began a postdoctoral fellowship at the school, working on an alternative polymer, poly (lactic-co-glycolic acid).

Article written by Virginia McMillan, for Pharmacy Today, November 2015