Harm reduction with syringe filters: an update on the evidence

Huei Ng Rahul Patel

Roger Latham Stuart McLean

Raimondo Bruno

School of Medicine University of Tasmania

Much of the harms from injection comes from non-drug contaminants

• Key contaminants

– Microorganisms (bacteria, fungi)

– Insoluble particles (environment, excipients)

• Effects

– Tissue & vein irritant (inflammation)

– Infections on skin/muscle injection (granuloma, abscesses)

– Local and systemic infection (bacteria & fungi)

• Undissolved particles

– Microcirculation: 5-10μm capilliaries

– Pulmonary circulation: 300-400μm arteries

• Granulomas in lungs

– Inflammation scar tissue (fibrosis) congmomerate masses restrictive lung disease & pulmonary hypertension

• Particulates also reach other organs (e.g. liver)

Common bacteria causing harms

Streptococcus pyogenes (SP)

Pseudomonas aeruginosa (PAO)

Staphylococcus aureus (SA)

Most common cause of soft tissue infections (abscesses, cellulitis) and more severe infections (endocarditis) often from consumers commensal flora

Examples of tablet excipients

Talc

Naturally occurring powder Tablet lubricant (1-10%) & diluent (5-30%) Typically: 99% <74um Will contain microorganisms Substantial evidence for accumulation in organs if IV

Hypromellose

Controlled-release coating agent (2-10%) Fibrous or granular powder Turns to gel (reversibly) at 50-90C

Methods

Preparation

• Drugs (MS Contin, OxyContin OC, subutex, suboxone strips) prepared following procedures reported by consumers

• Unfiltered and filtered using: cig filter;

0.45µm, 0.22µm, 0.8/0.2µm wheel filters

Particle counting and sizing • Light microscopy

• Samples from each preparation (x3)

• Counting from subtractive image

Drug Recovery • HPLC or spectrophotometry

Bacteria • Grown overnight on tryptone soy broth,

with 1.5% agar, at 35°C, filtered with tablet

Example: Neubauer blood counting slide (other lens contained scale)

4x magnification

Examples of filtered solutions (OxyContin 80mg)

unfiltered rollie + 0.45µm filtered

rollie + 0.22µm filtered

Cig. filtered

Examples of particle counts in unfiltered injections

MS Contin tablet Subutex tablet

Using a cigarette filter

Oxy

Co

nti

n (

OC

)

Sub

ute

x

Unfiltered Unfiltered

Filtered Filtered

How much do cigarette filters alone reduce particles?

D

Using a cigarette filter, then a wheel filter O

xyC

on

tin

(O

C)

Sub

ute

x

Unfiltered Unfiltered

Filtered Filtered

How much do cigarette filters in conjunction with 0.45μm wheel filters reduce particles?

Medical standard for ‘safe’ solution for injection (British Pharmacopeia, 2005):

no more than 3000 particles >10 µm; no more than 300 particles >25 µm

How much do cigarette filters in conjunction with 0.22μm wheel filters reduce particles?

Medical standard for ‘safe’ solution for injection (British Pharmacopeia, 2005):

no more than 3000 particles >10 µm; no more than 300 particles >25 µm

What about the single device filter (0.8/0.2µm)?

Medical standard for ‘safe’ solution for injection (British Pharmacopeia, 2005):

no more than 3000 particles >10 µm; no more than 300 particles >25 µm

Are filters still any good at removing bacteria when you push bacteria + tablets through?

Substantially worse than 0.22

Both below limits of detection

Yes, but do you lose your drug?

100 μm B

100 um C 100 μm D

Why not heating? Heating changes form of some excipients, if warm, these pass through filter and re-congeal. No benefits of heat compared with cold after filtering.

Excessive pressure

0.5/0.45 µm

Standard pressure

<1min >3min

Do

n’t

fo

rce

it!

OP Oxycontin: What to do?

• Citric? – Risk of fungal infection

– What is in the end product?

• Internet recipes – They exist, but…

– What is in the end product?

– Are the excipients gone?

– Are there harm from added chemicals in workarounds?

• Stakes are high – Risk of very significant venous

harms

• Swallowing is safe(r)

Reformulation: harder to break, viscous gel when liquid added

Conclusions

• Not injecting is safest

• Cloudy problem particles

• Heating is misleading

• If been handled (or in mouth) definitely use a wheel filter - remove large bacteria (e.g. Staphylococcus aureus, Candida)

• Don’t add excessive pressure

• Always swab to remove bacteria

Good:

• Filter with a rollie filter at least (and rinse)

• ~>90% dose; ~60% problem particles

Better:

• filter with rollie filter, rinse, then 0.22μm filter

• ~>90% dose; <95% particles; remove large bacteria

More betterer:

• 0.8/0.2μm filter

• ~>90% dose; <95% particles; remove large bacteria

Double filters need trialling (~$2/ea)

• Cost of hospital presentation: $3907 per avg admission (AG DHA, 2009)

• Estimated cost of treating IRID (exc. HIV/HCV) for Vic, NSW, Qld (community, ER, inpatient) $19m in 2005/06

• (Dwyer et al, Burnett Inst, 2007)