Estimated Cost of Injectable Medication Waste Attributable to Syringe Dead Space

Variation in syringes and needles dead space compared to the International Organization for Standardization standard 7886-1:2018

OBJECTIVE

To measure the dead space of various syringe volumes and brands and a range of needles gauges commonly used in clinical practice, and to compare the results to the International Organization for Standardization (ISO) standard 7886-1:2018.

STUDY DESIGN

Prospective observational study.

METHODS

Syringes of five brands and seven volumes: 1, 2.5, 5, 10, 20, 30, and 60 mL, 10 of each, 10 1 mL low dead space syringes and 10 23, 21 and 18 gauge needles were analysed. Syringe dead space was estimated by weighing each syringe, drawing up and expelling its rated volume of water for injection and re-weighing the syringe. The difference in mass between the two measurements was calculated and converted to a volume based on the density of water. The dead space of the needles was estimated using a similar technique: each needle was attached to a 1 mL syringe of known dead space. A Mettler electronic balance was used for the measurements. Mean dead space was calculated for each syringe volume and needle gauge. Data were compared to the ISO standard.

RESULTS

Syringe dead space for 1 and 2.5 mL was less than 0.07 mL. For 5 mL syringes four of five brands, and for 10 mL syringes one of five brands failed to comply with the ISO; the dead space was greater than 0.075 and 0.1 mL, respectively. For the 20, 30, 60 mL syringes the dead space was less than 0.2 mL. Needle dead space was 0.05 mL for 23 and 21 gauge, and 0.07 mL for 18 gauge, similar in order of magnitude to syringe dead space.

CONCLUSIONS

The dead space of syringes differs between brands, and some do not meet the ISO standard. When calculating the amount of drug lost due to dead space, both that of the syringe and needle used should be considered.

The Association between Needle Size and Waste Product and Its Effect on Cost-Effectiveness of Botulinum Toxin Injections?

Clostridium botulinum toxin (BT) must be administered intramuscularly with a syringe, but dead space in the syringe–needle complex may cause product waste and result in cost implications for the patient and provider. Syringe dead space is the volume of residual fluid that remains within the syringe after the plunger is fully depressed during medication injection. We calculated the average volume of remaining product in a syringe–needle complex and cost loss implication of this volume of BT. This is a single-center, analytical study using saline and four different sized needles for analytics of waste product and cost-effectiveness. Syringes of 1 mL with attached 18, 21, 30, and 32-gauge (G) needles, respectively, were compared. The syringe–needle complex was weighed before drawing 0.05 mL of saline. The fluid was then discarded with the appropriate syringe and then weighed again. This procedure was repeated for the four needle types and the average difference in weight of the syringe–needle complex before and after saline waste was measured. The volume was converted to units of BT used in clinical practice and the cost of waste product evaluated. The mean difference in needle–syringe complex weight before and after intervention was 0.068, 0.056, 0.04, and 0.026 g for the 18, 21, 30, and 32G needles, respectively. We found a statistically significant difference comparing the 18G with the 30 and 32G (0.02 and 0.0007, respectively) and comparing the 21G with the 30 and 32G (0.0042 and 0.00002, respectively). When we extrapolated the data to BT units (4U/0.1 mL), we found that theoretically 2.72, 2.24, 1.6, and 1.04 units of BT are left in the syringe–needle complex for the 18, 21, 30, and 32G syringes, respectively. At a cost of $6.01/U of onabotulinum toxin A, we then calculated a provider loss of a gross average (mean) revenue of $96 and 62.4 per 10 syringes used with 30 and 32G needles. Needle size used for drawing up and administering BT has an effect on the amount of waste product and subsequently on cost-effectiveness.

Modeling, design, and machine learning-based framework for optimal injectability of microparticle-based drug formulations

Inefficient injection of microparticles through conventional hypodermic needles can impose serious challenges on clinical translation of biopharmaceutical drugs and microparticle-based drug formulations. This study aims to determine the important factors affecting microparticle injectability and establish a predictive framework using computational fluid dynamics, design of experiments, and machine learning. A numerical multiphysics model was developed to examine microparticle flow and needle blockage in a syringe-needle system. Using experimental data, a simple empirical mathematical model was introduced. Results from injection experiments were subsequently incorporated into an artificial neural network to establish a predictive framework for injectability. Last, simulations and experimental results contributed to the design of a syringe that maximizes injectability in vitro and in vivo. The custom injection system enabled a sixfold increase in injectability of large microparticles compared to a commercial syringe. This study highlights the importance of the proposed framework for optimal injection of microparticle-based drugs by parenteral routes.

Options for reducing HIV transmission related to the dead space in needles and syringes

BACKGROUND

When shared by people who inject drugs, needles and syringes with different dead space may affect the probability of HIV and hepatitis C virus (HCV) transmission differently.

METHODS

We measured dead space in 56 needle and syringe combinations obtained from needle and syringe programs across 17 countries in Europe and Asia. We also calculated the amounts of blood and HIV that would remain in different combinations following injection and rinsing.

RESULTS

Syringe barrel capacities ranged from 0.5 to 20 mL. Needles ranged in length from 8 to 38 mm. The average dead space was 3 μL in low dead space syringes with permanently attached needles, 13 μL in high dead space syringes with low dead space needles, 45 μL in low dead space syringes with high dead space needles, and 99 μL in high dead space syringes with high dead space needles. Among low dead space designs, calculated volumes of blood and HIV viral burden were lowest for low dead space syringes with permanently attached needles and highest for low dead space syringes with high dead space needles.

CONCLUSION

The dead space in different low dead space needle and syringe combinations varied substantially. To reduce HIV transmission related to syringe sharing, needle and syringe programs need to combine this knowledge with the needs of their clients.