The local pharmacokinetics of ³H-ropivacaine and ¹⁴C-lidocaine after maxillary infiltration anesthesia in rats

Exploration of the Influences of Temporary Velum Paralysis on Auditory-Perceptual, Acoustic, and Tomographical Markers

Purpose To better understand hypernasality (HN), we explored the relations between velopharyngeal orifice, auditory perception of HN, and acoustic-spectral measures in an in vivo within-subject design: (a) with a normally functioning velum as the control condition and (b) with a temporarily paralyzed velum as the experimental condition. Method The velum of eight volunteers was injected with ropivacaine hydrochloride (Naropin) in the area of the levator veli palatini and tensor veli palatini muscles to induce temporary velopharyngeal inadequacy (VPI) and HN. Sustained [a] and [i] and oronasal text readings were recorded, and 3D cone-beam computed tomography images of the vocal tract were built before and during velar anesthesia. Differences between conditions and correlations in normal-to-numb differences between velopharyngeal cross-sectional area (VP_area), mean ratings of HN severity, and nine acoustic-spectral measures were determined. Results Three subjects already had some incomplete velopharyngeal closure in the control condition. Temporary motor nerve blockage of the velum (increased VP_area) was accomplished in seven subjects, leading to increased HN and changes in three acoustic-spectral measures. Furthermore, significant correlations only emerged between VP_area, HN, and Model_Kataoka. Conclusions In most of the participants, it was possible to temporarily increase the velopharyngeal orifice to investigate HN while controlling other speech variables and cephalic morphology. Although this study was exploratory and its are findings preliminary, it provided additional evidence for the possible clinical value of Model_Kataoka, A ₃-P ₀, and B _F1 for the objective measurement of VPI or HN.

Does local injection of reveromycin A inhibit tooth movement without causing systemic side effects?

OBJECTIVE

To determine the feasibility of local inhibition of osteoclast activity and control of tooth movement with local intraoral reveromycin A (RMA) injection in model mice for experimental tooth movement.

MATERIALS AND METHODS

Eight-week-old wild-type mice (n = 6 per group) were divided into four groups consisting of two non-RMA groups that received normal saline for 14 (14-day non-RMA group) or 21 consecutive days (21-day non-RMA group) and 2 RMA groups that received RMA (1.0 mg/kg of weight) for 14 (14-day RMA group) or 21 consecutive days (21-day RMA group). RMA was injected locally into the buccal mucosa of the left first maxillary molar twice daily starting 3 days before placement of the 10-gf Ni-Ti closed coil spring. Tooth movement distance was analysed using micro-computed tomography. The effects on surrounding alveolar bone were evaluated by measuring the ratio of bone surface area to tissue surface area with haematoxylin-eosin-stained sections and counting the number of osteoclasts in periodontal tissue with TRAP-stained sections. Blood tests were performed and bone volume and trabecular separation at the tibial neck were measured to analyse systemic side effects.

RESULTS

Local RMA injection inhibited tooth movement by 40.6 per cent, promoted alveolar bone volume maintenance by 37.4 per cent, and inhibited osteoclast activity around the tooth root at 21 days by 40.8 per cent. Systemic effects on osteoclasts or osteoblasts were not observed.

CONCLUSION

Local injection of RMA enabled control of tooth movement without systemic side effects in a mouse model.

Comparison of anaesthetic efficacy of ropivacaine (0.75% & 0.5%) with 2% lignocaine with adrenaline (1:200000) in surgical extraction of bilateral mandibular 3rd molars using IANB:a prospective, randomized, single blind study

Aim

To evaluate and compare the anaesthetic efficacy of 0.75% ropivacaine and 0.5% ropivacaine with 2% lignocaine with 1:200000 Adrenaline (LWA) for surgical extraction of bilateral mandibular 3rd molars using Direct inferior alveolar nerve block (IANB).

Material and methods

Total of 60 outpatients of both sex,age group of 18-40 included in a prospective, randomized, single blind, split mouth clinical study after satisfying inclusion and exclusion criteria. Group I includes 30 patients and 0.75% ropivacaine as test drug, Group II includes 30 patients and 0.5% ropivacaine as test drug. In both group control drug was LWA.Parameters measured were onset of action, duration of action, systolic blood pressure, diastolic blood pressure, heart rate, visual analogue scale (VAS), faces pain scale (FPS).

Result

Onset of action of 0.75%/0.5% ropivacaine (101.84 ​± ​16.92 ​secs/113.03 ​± ​12.77 ​sec) was faster than LWA (Group I-218 ​± ​21.51 ​secs, Group II-196.47 ​± ​26.27 ​secs). Duration of action of 0.75%/0.5% ropivacaine (343.55 ​± ​16.44 ​mins/319.03 ​± ​19.30 ​mins) was longer than 2% Lignocaine with 1:200000 adrenaline (Group I I-173 ​± ​16.86 ​mins, Group II-175.20 ​± ​18.02 ​mins). In Group I - VAS/FPS of 0.75% Ropivacaine (0.97 ​± ​0.54/1.32 ​± ​0.65) was significantly lower as compared to LWA (2.90 ​± ​0.83/3.29 ​± ​0.69). In group II-VAS/FPS of 0.5% ropivacaine (1.40 ​± ​0.72/1.47 ​± ​0.50) was lower as compared to LWA (3.40 ​± ​0.89/3.30 ​± ​0.87). Mean systolic blood pressure, diastolic blood pressure, heart rate was lower for ropivacaine (0.75%, 0.5%) than LWA except mean heart rate higher for 0.75% ropivacaine at 10 ​min after injection. Else mean heart rate lower in other time interval.

Conclusion

Ropivacaine (0.75%,0.5%) was more efficacious than 2% lignocaine with adrenaline (1:200000) it terms of all measured parameters in study.

Effect of epinephrine on the distribution of ropivacaine and lidocaine using radioactive isotopes in rat maxilla and pulp

We compared the effect of epinephrine on the distribution of ropivacaine and lidocaine by using radioactive isotopes in rat maxilla and pulp. Twenty microliters of 3H-labeled 0.5% ropivacaine, 14C-labeled 2.0% lidocaine, or epinephrine-supplemented isotopes were injected into the maxilla. The radioactivity was measured and autoradiography was obtained. Epinephrine led to increase in amounts of both anesthetics in the maxilla and pulp; however, each anesthetic did so in a different manner. Addition of epinephrine to lidocaine decreased radioactivity in maxilla and pulp with time. Conversely, when ropivacaine with epinephrine was administered, radioactivity did not change until 20 min in the maxilla and reached its peak at 20 min in the pulp. Autoradiography of lidocaine faded with time even with epinephrine use; however, with ropivacaine, higher accumulation image was observed after 20 min compared to that after 2 min. When epinephrine was combined with lidocaine, the amount of lidocaine in maxilla and pulp decreased with time, similar to when lidocaine was used alone. Conversely, when ropivacaine-epinephrine combination was administered, the amount of ropivacaine remained unchanged for 20 min in the maxilla and reached its peak at 20 min in the dental pulp.

Impact of dexmedetomidine on the tissue distribution, anesthetic action, and hemodynamic effects of mepivacaine

The present study investigated the regional blood flow, tissue distribution, local anesthetic action, and hemodynamic effects of mepivacaine containing dexmedetomidine hydrochloride (DEX) in rats. Blood flow was measured after injection of 0.5% mepivacaine (M group), 12.5 µg/ml DEX (D group), or 0.5% mepivacaine containing 12.5 µg/ml DEX (DM group) into the upper lip. Mepivacaine distribution was autoradiographically observed in maxillary bone resected after injection of 0.5% ³H-mepivacaine (HM group) or 0.5% ³H-mepivacaine containing 12.5 µg/ml DEX (DHM group) into the palatal mucosa adjacent to the right maxillary first molar. Radioactivity was also measured using a liquid scintillation counter. SEP were measured to analyze anesthetic action. Blood pressure and heart rate were measured to compare hemodynamic effect. The addition of DEX significantly decreased blood flow compared to M group from 10 to 60 min after injection. The addition of DEX significantly increased the amount of radioactivity compared to HM group in the palatal mucosa from 5 to 60 min after injection and in the body of the maxilla from 2 to 60 min after injection. Maximum blood radioactivity was measured at 5 min after injection in HM group and 50 min after injection in DHM group. The addition of DEX significantly decreased peak-to-peak amplitudes compared to M group until 60 min after injection. No significant hemodynamic differences were observed. DEX enhances the action of mepivacaine in reducing regional blood flow prolongs its tissue retention, and increases the local anesthetic action without affecting hemodynamics on local administration.

The effect of two drug delivery systems in ropivacaine cytotoxicity and cytokine release by human keratinocytes and fibroblasts

Objectives

Modified drug delivery systems have been developed to improve pharmacological properties of local anaesthetics. However, the inflammatory potential of these formulations was not investigated. This study compared the in-vitro effects of ropivacaine (ropi) in plain, liposomal (MLV) or 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) formulations on cell viability, apoptosis and cytokine (IL-1α, TNF-α, IL-6 and IL-10) release.

Methods

Human immortalized keratinocytes (HaCaT) and human immortalized gingival fibroblasts (HGF) were exposed to 1–100 μm ropi concentrations. The cell viability was measured by XTT and LIVE/DEAD assay. Apoptosis was performed by flow cytometry, and cytokine release was measured by ELISA assay.

Key findings

Human immortalized keratinocyte viability was reduced by ropi and both drug delivery systems. However, none of the formulations induced apoptosis. Results showed a differential regulation of IL-1α TNF-α, IL-6 and IL-10 by HaCaT and HGF. Ropi-HP-β-CD increased twofold the IL-6 release by HGF in comparison with the control, while 100 μm ropi-MLV led to an increased release of all pro-inflammatory cytokines by HGF.

Conclusion

The loss in cell viability was not related to cellular apoptosis. Ropi complexed with HP-β-CD showed a similar cytokine release pattern when compared to the plain formulation. Thus, the HP-β-CD form was a better drug carrier than the MLV form for ropivacaine drug delivery.

Epinephrine Affects Pharmacokinetics of Ropivacaine Infiltrated Into Palate

Pulpal anesthesia success rates for ropivacaine following maxillary infiltration anesthesia seem to be low. We investigated the hypothesis that the addition of epinephrine would affect the pharmacokinetics of ropivacaine by retaining ropivacaine in the mucosa of the injected area through the time-dependent distribution of ropivacaine in the rat maxilla and serum following maxillary infiltration anesthesia using (3)H-labeled ropivacaine. We then examined the vasoactivity of ropivacaine with or without epinephrine on local peripheral blood flow. The addition of epinephrine to ropivacaine increased ropivacaine concentrations in the palatal mucosa and adjacent maxilla by more than 3 times that of plain ropivacaine at 20 minutes. By observing the autoradiogram of (3)H-ropivacaine, plain ropivacaine in the maxilla was remarkably reduced 20 minutes after injection. However, it was definitely retained in the palatal mucosa, hard palate, adjacent maxilla, and maxillary nerve after the administration with epinephrine. Ropivacaine with epinephrine significantly decreased labial blood flow. This study suggests that 10 μg/mL epinephrine added to 0.5% ropivacaine could improve anesthetic efficacy and duration for maxillary infiltration anesthesia over plain ropivacaine.

Efficacy and safety of 1% ropivacaine for postoperative analgesia after lower third molar surgery: a prospective, randomized, double-blinded clinical study

OBJECTIVES

The purpose of this study was to investigate postoperative analgesic effect of ropivacaine administered as main or supplemental injection for the inferior alveolar nerve block (IANB) in patients undergoing lower third molar surgery.

MATERIALS AND METHODS

The double-blind randomized study comprised 72 healthy patients. All patients received two blocks, the IANB for surgical procedure + IANB after surgery for postoperative pain control, and were divided into three groups: (1) 2 % lidocaine/epinephrine + 1 % ropivacaine, (2) 2 % lidocaine/epinephrine + saline, and (3) 1 % ropivacaine + saline. The occurrence of postoperative pain, pain intensity and analgesic requirements were recorded. Data were statistically analyzed using chi-square, Fisher, and Kruskal-Wallis tests and analysis of variance (ANOVA) with Bonferroni and Tukey correction.

RESULTS

Ropivacaine was more successful than lidocaine/epinephrine in obtaining duration of postoperative analgesia, reduction of pain, and analgesic requirements whether ropivacaine was used for surgical block or administered as a supplemental injection after surgery.

CONCLUSIONS

Ropivacaine (1 %, 2 ml) resulted in effective postoperative analgesia after lower third molar surgery.

CLINICAL RELEVANCE

Since pain control related to third molar surgery requires the effective surgical anesthesia and postoperative analgesia, the use of 1 % ropivacaine could be clinically relevant in a selection of appropriate pain control regimen for both surgical procedure and early postsurgical treatment.

Effects of epinephrine on lidocaine pharmacokinetics and blood volume in the dental pulp

INTRODUCTION

Epinephrine potentiates and prolongs the efficacy of local anesthetics by reducing blood flow. We investigated the effect of epinephrine on the pharmacokinetics of lidocaine and the pulpal blood volume after maxillary infiltration anesthesia in rats.

METHODS

We measured the (14)C-radioactivity and (14)C-distribution in the maxilla and the dental pulp after the injection of 2% (14)C-lidocaine with or without 10 μg/mL epinephrine (n = 7) into the palatine mucosa proximal to the first molar. The blood volume in the pulp was measured using (99m)Tc-pertechnetate (n = 5).

RESULTS

When lidocaine was injected together with epinephrine, the lidocaine became widely distributed throughout the maxilla and was observed mainly in the first molar pulp. The lidocaine amount in the dental pulp at 10-60 minutes was more than 2 times higher than that after the injection of lidocaine alone. The relative pulpal blood volume after 20 minutes decreased to 63.1% of the value after the injection of lidocaine alone.

CONCLUSIONS

We found that lidocaine had infiltrated into the molar pulp after infiltration anesthesia. Furthermore, our results suggested that epinephrine augmented the retention of lidocaine in the pulp.