Background and Importance Intravitreal injection is a very common eye surgery. The preparation of the injection is time-consuming and labour-intensive, because patients receive several ophthalmic drugs beforehand like locally disinfecting, pupil dilating and local anaesthetic eye drops. Additionally, eye drops containing oxybuprocaine must be applied 3 to 5 times at minute intervals for a sufficient anaesthetic effect.

Aim and Objectives To simplify the process, a local anaesthetic eye gel preparation was requested. The increased viscosity leads to a longer local exposure time on the eye. A single dose is therefore sufficient to achieve the required local anaesthetic effect. As far as we know, a corresponding product is not available on the German market, so an in-house product was developed.

Material and Methods The active ingredient lidocaine hydrochloride 2% (w/w) is dissolved in hot WFI with 0.48% (w/w) sodium chloride as an isotonizing additive. 0.25% (w/w) sodium monohydrogen phosphate x 12 H2O, leads to a pH value of 6 -7 in the finished gel. pH 7 must not be exceeded, to prevent precipitation of lidocaine base. Hydroxyethylcellulose 250 (Natrosol 250 G pharm®), a sterilizable gelling agent, is incorporated into the hot solution at a concentration of 2.5% (w/w). After cooling, WFI is added to the full batch weight, the batch is stirred vigorously and left to stand covered overnight. A homogeneous gel of suitable viscosity develops overnight. The following day, the gel is filled into Redipac® single-dose containers with subsequent autoclaving under standard conditions.

The identity and content of the preparation is checked by UV/VIS spectroscopy.

Results The preparation described achieves a sufficient local anaesthetic effect after single application, is free of preservatives and can be stored at room temperature.

Conclusion and Relevance The lidocaine gel in single-dose containers has significantly accelerated and simplified the preparation of intravitreal injections in the UKSH Eye Clinic.