Nanotechnology application to local anaesthesia (LA)

Figures & data

Figure 1. Showing bupivacaine – chemical structure. This figure was culled from [12].

Table 1. Showing summary of clinical trials investigating the efficacy of different nano-formulations in local anaesthesia. This table was culled from [19].

Formulations tested	Test method	Site and duration of application	Clinical study characteristics	Most effective formulation	Reference
Liposome encapsulated 5% tetracaine versus 20% benzocaine gel	Pain during needle insertion and LA injection	Not available	30 volunteers; double-blind, split-mouth design	Liposomal tetracaine	[20]
Transoral lidocaine delivery system versus placebo; 20% benzocaine gel	Pain during needle stick with a 25 G needle	Buccal gingiva apical to the molar-bicuspid pair in the maxilla or mandible	20 patients, randomized, placebo- controlled study.	DentiPatch	[21]
Transoral lidocaine delivery system versus placebo; 20% benzocaine gel versus placebo.	Pain during needle stick with a 25 G or 27 G needle.	Buccal gingiva apical to the molar-bicuspid pair in the maxillary arch	20 patients, randomized, placebo-controlled, double-blinded study.	DentiPatch	[22]
Lidocaine mucoadhesive patch.	Gingival anaesthesia for rubber dam clamp placement	Buccal or lingual gingiva ∼1 mm from the first two premolars	28 children, randomized, split-mouth design study.	All formulations tested were equally effective.	[23]
1% liposomal ropivacaine gel versus 1% plain ropivacaine gel; 20% benzocaine gel.	Pain during needle insertion	Maxillary right canine buccal fold.	30 volunteer subjects, randomized, blinded, cross-over study	Liposomal ropivacaine	[24]
2% liposomal ropivacaine gel versus 1% liposomal ropivacaine gel.	Pain during needle insertion.	Palatal mucosa at the right canine region.	40 volunteers subjects, randomized, single-blinded, placebo-controlled study.	No difference among anaesthetic formulations and placebo	[25]
Liposome-encapsulated 2% lignocaine with epinephrine	Repeated pinprick tests with a periodontal probe.	At the junction between the vertical and horizontal parts of the mucosa near the roots of the upper first molars.	32 volunteers subjects	Liposomal lignocaine with epinephrine	[26]
Liposome-encapsulated 5% lidocaine versus 5% lidocaine gel	Pain during needle insertion.	Maxillary buccal fold at the canine region bilaterally	No volunteers, randomized, double- blinded, placebo-controlled study.	Liposomal lidocaine	[27]
Lidocaine transmucosal delivery system	Pain during scaling	Buccal gingiva apical to the treated area in maxilla.	40 volunteers single-blind, randomized, two treatment, placebo- controlled study.	Only dentipatched was evaluated and was effective	[28]
1% liposomal ropivacaine gel versus 1% plain ropivacaine gel.	Pain during needle insertion	Maxillary right canine buccal fold	30 subjects, randomized, blinded, cross-over study	Liposomal ropivacaine	[24]

Figure 2. Showing the plasma bupivacaine concentration after administration of DepoFoam bupivacaine or bupivacaine HCl to patients undergoing total knee arthroplasty. This figure was culled from [32].

Figure 3. Showing atomic force microscope image of PCL nanospheres loaded with LDC. Culled from [44].

Table 2. Showing summary of nano-formulated materials used for local anaesthesia. Culled from [51].

Nano-materials	Formulations	References
Nanorod	Gold nanorod-liposomes-tetrodotoxin	[50]
Micro-particles	PLGA-micro-particle-LDC	[47–49]
Nanospheres or nanocapsules	nanosphere-poly(D,L-lactic acid)-LDC, poly(ɛ-Caprolactone)-nanospheres-LDC, poly(ethylene-glycol)-poly(ɛ-caprolactone)-nanosphere-LDC nanocapsules-poly(L- lactide) compared to benzocaine-loaded PNs	[43–46]
Hydrogel	Poloxamer-407 hydrogels-mebeverine, Genipin cross-linked catechol-chitosan hydrogel-LDC	[40,41]
Nanoparticles	Lipid–polymer hybrid nanoparticles-LDC, nanoparticles-PCL-LDC	[36,38]
Cyclodextrin	β-CD-LDC	[34]

Figure 4. Showing characterization of blank liposomes conjugated with gold nanorods (Lip-GNR) and cryo-electron microscope image displaying gold nanorods (yellow arrows). Culled from [50].

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