Preservatives are necessary evils in the conventional three piece multi dose eye drop vial, as the ambient non-sterile as well as the left over drop exposed to ambience environment renters in the vial from the same path as that of the drug flow path contaminating the liquid inside.
Preservatives are added, as mandated, to prevent the growth of microbial contaminants and biodegradation in the formulations. Thus, preservatives have become a key component in ophthalmic formulations to keep the sterility of the product, widely used preservatives are:
- Benzalkonium chloride (BAC/BAK),
- Stabilised Oxychloro Complex (SOC)
Though preservatives help keep the formulation sterile over the course of multiple uses, various studies have proved that preservatives used in long term therapy induces ocular toxicity and causes harmful effects to your eyes such as Tear film instability, Conjunctival inflammation, Ocular discomfort, Corneal Surface impairment and more mentioned in Table 1.
Novelia,’ a technology from France, brought in India for the first time by Kilitch Healthcare India Limited, is the solution that provides the benefits of the medication without the ill effects of any preservatives.
The state-of-the-art patented pure flow technology prevents bacterial contamination and avoids the need of preservatives in the formulation.
Benefits major of these preservative-free multi dose formulations are listed in Table 2.
Working of the preservative free system in can be better understood correlating the below process shown in Table 3.
On squeezing the bottle the liquid flows out of the bottle through a defined path dispensing uniform dosage (o)
Contaminated air (o) or contaminated liquid from atmosphere cannot flow back into the bottle due to the presence of non-return valve in the nozzle. (o)
Air compensation happens by entry of ambient air or liquid from ambient atmosphere through the aperture pro- vided on the side of the bottle, through the continous silicon membrane which allows only gases to flow through, arresting the microbes. (o)
The functioning of the system can be summarised in a nutshell in four simple steps as mentioned in Table 4.
In Novelia bottles main functions are achieved by
Valve system: which opens to deliver accurate drop and closes to avoid any backflow
Venting system: which allows only the filtered sterile air to enter the device after drop delivery due to the presence of silicone membrane.
Major challenge test done to prove the ability of above functions:
- To challenge the valve system tightness to micro organisms with vaccum in the container.
- To challenge the ability of venting system to protect content against contamination ingress.
- To challenge the ability of Novelia bottle to keep the contents sterile even after repetative contact of the tip of the device with contamination.
- To challenge the ability to keep contents sterile during a three-month treatment and to check that Novelia bottles has the same functioning after three months of use.
- To challenge the compatability between the Novelia silicon parts and our formulations.
Novelia bottles pass in all the above challenge test, demonstrating that the different technical functions of Novelia are able to protect content against contamination.
Does preservative help to keep the drop efficacy?
Preservatives are added to formulations to prevent decomposition of drug content due to microbial growth. In traditional eye dropper bottle, as external ambient non-sterile air comes in contact with the drug, inducing microbial growth, preservatives are added. It is myth to say that preservatives help to keep the drop efficacy.
In Novelia technology does the efficacy of the product remains same even after one month of opening the cap?
In Novelia technology, ambiant non sterile air passes through the homogenous silicone membrane, blocking any potential bacteria and only allowing gasses to flow through, hence the product remains sterile and efficient all throughout its shelf life even after opening.
Preservatives have no effect on efficacy of drug, so drops even after one month will be sterile and as efficient as first drop.
Does the residual drop on the tip of the bottle get wasted?
In Novelia technology during instillation even if there is a residual drop remaining on the tip of the bottle, it does not get wasted for the following reasons:
- On closing of the bottle with the cap, the drop remains sterile as the inner surface of the cap and the top of the bottle contains silver ions which avoids any bacteria growth
- When it is squeezed for a second time, this residual drop will be part of the new drop.