Optimization of Influential Variables in the Development of Buprenorphine and Bupivacaine Loaded Invasome for Dermal Delivery

Purpose: Hydrophilic drugs are extensively applied in clinical applications. Inadequate dermal penetration of these drugs is a great challenge. Incorporation of drugs into nano-carrier systems overcomes lower penetration drawbacks. Invasomes are novel nano-carrier systems which enhance transdermal penetration by using terpene and ethanol in their structures. buprenorphine and bupivacaine hydrochlorides are two potent analgesic drugs that are loaded simultaneously in the nano-invasome structure as opioid and non-opioid drugs.

Methods: The full factorial experimental design was used for planning and estimating optimum formulations of invasome systems. Three influential factors like terpene type, terpene concentration and preparation method were comprehensively analyzed for achieving high encapsulation efficiency (EE) and optimum size.

Results: The mean sizes of designed invasomes were in the range of 0.39-5.86 µm and high values of EE and loading capacity (LC) were reported as 98.77 and 19.75 for buprenorphine-loaded invasome, respectively. Zeta potential measurements confirmed that the obtained high value of EE might be as a result of reversible ionic interactions between positively charged drugs and negatively charged phospholipidic part of invasome structure. Another characterization of the prepared formulations was carried out by Fourier transform infrared (FTIR), X-ray diffraction (XRD) and dynamic light scattering (DLS) technique.

Conclusion: The satisfactory obtained results of formulations encourage researchers to get optimum topical analgesic formulations with potent and rapid onset time properties required in invasive cutaneous procedures.

Study of Peri-Articular Anaesthetic for Replacement of the Knee (SPAARK): statistical analysis plan for a randomised controlled trial assessing the effectiveness of peri-articular liposomal bupivacaine plus bupivacaine hydrochloride compared with bupivacaine hydrochloride alone

Background

Up to three quarters of surgical patients receive inadequate pain relief, with 40% of patients reporting severe pain following knee replacement, which may indicate the current pain relief strategies using opiate-based analgesia cannot achieve patient satisfaction. Liposomal bupivacaine is liposome-encapsulated bupivacaine which has been reported to be effective for up to 72 h. The study of Peri-Articular Anaesthetic for Replacement of the Knee (SPAARK) trial has been designed to assess the effectiveness of peri-articular liposomal bupivacaine and bupivacaine hydrochloride compared with peri-articular bupivacaine hydrochloride alone in the management of post-operative pain following knee replacement.

Methods/design

The SPAARK trial is a multi-centre, patient-blinded, randomised controlled trial. The co-primary outcomes are post-operative recovery assessed by global QoR-40 scores at 72 h and cumulative pain VAS score from 6 to 72 h following surgery. Longer-term measures of the co-primary outcomes are collected at 6 weeks and 6 and 12 months post randomisation, together with secondary outcomes, i.e. the Oxford Knee Score, and the American Knee Society Score. Cumulative opiate use and fitness for discharge are measured up to 72 h post-surgery. The analysis approaches for the primary and secondary outcomes are described here, as are the descriptive statistics which will be reported. The full SPAARK protocol has already been published.

Results

The co-primary outcomes will be analysed using multivariate linear regression adjusting for stratification factors and other important prognostic variables, including baseline scores in the case of the QoR-40. The adjusted mean difference between the two groups together with 97.5% confidence intervals will be reported for each of the primary outcomes. Other continuous variables will be assessed using the same method. Binary outcomes will be assessed using chi-squared tests.

Discussion

The paper provides details of the planned statistical analyses for the SPAARK trial and aims to reduce the risk of outcome reporting bias from prior data knowledge. Any changes or deviations from this statistical analysis plan will be described and justified in the final study report.

Trial registration

ISRCTN54191675. Registered on 13 November 2017.

Local Retropharyngeal Space Anesthetic for Dysphagia Reduction after Anterior Cervical Discectomy and Fusion Surgery: A Single-Center, Prospective, Randomized, Double-Blinded, Placebo-Controlled Clinical Trial

OBJECTIVE

The main objective of this study was to analyze the ability of local anesthetic instillation into the retropharyngeal space to reduce dysphagia symptoms and occurrence rates in patients undergoing anterior cervical discectomy and fusion (ACDF) procedures.

METHODS

A single-center, prospective, randomized, double-blinded, and placebo-controlled clinical study was performed. We enrolled patients undergoing one- or two-level ACDF procedures for cervical degenerative disc disease with disc herniation, radiculopathy and/or myelopathy symptoms. The patients were randomly assigned (1:1 ratio) to receive either 0.5% bupivacaine hydrochloride or 0.9% NaCl solution.

RESULTS

Forty-three (74%) and 41 (77%) of patients reported dysphagia symptoms at the time of discharge in the investigational and control groups, respectively. There were no statistically significant differences in duration of dysphagia symptoms, Swallowing-Quality of Life (SWAL-QOL) survey or pain scores between the investigational and control patient groups at any of the follow-up time points. Controlling for independent variables, only younger age significantly predicted dysphagia symptoms at discharge, 2-week, and 3-month follow-ups (P ≤ 0.03; R ≥ -0.038; OR 0.96, 95% CI 0.93-0.99. Female sex was associated with lower SWAL-QOL scores at discharge (P = 0.046; R = 0.87; OR 2.38, 95% CI 1.02-5.56). A total of 8 (13.8%) and 6 (11.3%) patients in the investigational and control groups, respectively, were referred to a specialist or underwent speech therapy for their dysphagia symptoms. There were no adverse reactions to the study drug observed.

CONCLUSIONS

Local retropharyngeal space anesthetic instillation did not reduce dysphagia symptoms or occurrence rates in patients undergoing anterior discectomy and fusion surgeries.

Neurotoxicity of bupivacaine and liposome bupivacaine after sciatic nerve block in healthy and streptozotocin-induced diabetic mice

Background

Long-acting local anaesthetics (e.g. bupivacaine hydrochloride) or sustained-release formulations of bupivacaine (e.g. liposomal bupivacaine) may be neurotoxic when applied in the setting of diabetic neuropathy. The aim of the study was to assess neurotoxicity of bupivacaine and liposome bupivacaine in streptozotocin (STZ) - induced diabetic mice after sciatic nerve block. We used the reduction in fibre density and decreased myelination assessed by G-ratio (defined as axon diameter divided by large fibre diameter) as indicators of local anaesthetic neurotoxicity.

Results

Diabetic mice had higher plasma levels of glucose (P < 0.001) and significant differences in the tail flick and plantar test thermal latencies compared to healthy controls (P < 0.001). In both diabetic and nondiabetic mice, sciatic nerve block with 0.25% bupivacaine HCl resulted in a significantly greater G-ratio and an axon diameter compared to nerves treated with 1.3% liposome bupivacaine or saline (0.9% sodium chloride) (P < 0.01). Moreover, sciatic nerve block with 0.25% bupivacaine HCl resulted in lower fibre density and higher large fibre and axon diameters compared to the control (untreated) sciatic nerves in both STZ-induced diabetic (P < 0.05) and nondiabetic mice (P < 0.01). No evidence of acute or chronic inflammation was observed in any of the treatment groups.

Conclusions

In our exploratory study the sciatic nerve block with bupivacaine HCl (7 mg/kg), but not liposome bupivacaine (35 mg/kg) or saline, resulted in histomorphometric indices of neurotoxicity. Histologic findings were similar in diabetic and healthy control mice.

The role of port site local anesthetic injection in laparoendoscopic single site surgery: a prospective randomized study

Objective

To investigate the role of port-site bupivacaine hydrochloride injection in laparoendoscopic single-site surgery (LESS) as a means of postoperative umbilical pain alleviation.

Methods

A total of 200 consecutive patients who underwent LESS from October 2018 to February 2019 were included in this randomized prospective case control study. The patients were alternatively assigned to either the study group (0.25% 10-mL bupivacaine hydrochloride injection at the 1.5-cm umbilical incision site after surgery) or the control group (no injection). All patients underwent surgery at the National Health Insurance Service Ilsan Hospital under the same operational setting by 3 board-certified gynecologists. Postoperative umbilical pain scores assessed using the visual analog scale were compared between the 2 groups as the primary outcome. Student's t-test, χ² test, and a linear mixed model were used for the statistical analysis. A P-value of <0.05 was considered to be statistically significant.

Results

The patients' age, body mass index, and menopausal status; type of surgery performed; and need for additional trocar insertion exhibited a significant difference between the bupivacaine injection and non-injection groups. After adjusting for various confounding variables, the postoperative umbilical pain scores measured at postoperative 2–3 hours, 6–10 hours, 1 day, and 3 days did not exhibit a significant difference between the 2 groups.

Conclusion

Port-site bupivacaine injection in LESS did not show any additive effect in alleviation of postoperative umbilical pain.

Intraperitoneal bupivacaine alone or with dexmedetomidine or tramadol for post-operative analgesia following laparoscopic cholecystectomy: A comparative evaluation

Background and Aims:

Intraperitoneal instillation of local anaesthetics has been shown to minimise post-operative pain after laparoscopic surgeries. We compared the antinociceptive effects of intraperitoneal dexmedetomidine or tramadol combined with bupivacaine to intraperitoneal bupivacaine alone in patients undergoing laparoscopic cholecystectomy.

Methods:

A total of 120 patients were included in this prospective, double-blind, randomised study. Patients were randomly divided into three equal sized (n = 40) study groups. Patients received intraperitoneal bupivacaine 50 ml 0.25% +5 ml normal saline (NS) in Group B, bupivacaine 50 ml 0.25% + tramadol 1 mg/kg (diluted in 5 ml NS) in Group BT and bupivacaine 50 ml 0.25% + dexmedetomidine 1 μg/kg, (diluted in 5 ml NS) in Group BD before removal of trocar at the end of surgery. The quality of analgesia was assessed by visual analogue scale score (VAS). Time to the first request of analgesia, total dose of analgesic in the first 24 h and adverse effects were noted. Statistical analysis was performed using Microsoft (MS) Office Excel Software with the Student's t-test and Chi-square test (level of significance P = 0.05).

Results:

VAS at different time intervals, overall VAS in 24 h was significantly lower (1.80 ± 0.36, 3.01 ± 0.48, 4.5 ± 0.92), time to first request of analgesia (min) was longest (128 ± 20, 118 ± 22, 55 ± 18) and total analgesic consumption (mg) was lowest (45 ± 15, 85 ± 35, 175 ± 75) in Group BD than Group BT and Group B.

Conclusion:

Intraperitoneal instillation of bupivacaine in combination with dexmedetomidine is superior to bupivacaine alone and may be better than bupivacaine with tramadol.

A comparison of the efficacy of topical application of Lignocaine Hydrochloride 5% gel and Bupivacaine Hydrochloride 5% gel for extraction of teeth

BACKGROUND

With the advancements in dentistry the treatments are done with high perfections and patient comfort. Noninvasive, methods reduce fear and anxiety of the patient on phobia of syringes and injections. Topical anesthesia satisfies all the above criteria.

AIM AND OBJECTIVE

Comparison of the efficacy of topical application of lignocaine hydrochloride 5% gel and bupivacaine hydrochloride 5% gel for extraction of teeth.

MATERIALS AND METHODS

Lignocaine hydrochloride 5% gel and bupivacaine hydrochloride 5% gel are prepared with carbopol (thickening agent). 510 extractions with lignocaine hydrochloride gel 5% and bupivacaine hydrochloride gel 5% in equal numbers was undertaken. Parameters of onset of anesthesia, peak effects, pain, and disappearance of numbness, local irritation, bleeding and periodontal status of teeth to be extracted were taken into consideration.

RESULTS

Onset and peak effect were faster with 5% lignocaine hydrochloride gel. 5% bupivacaine hydrochloride gel had longer duration of analgesia. Patients experienced more pain with bupivacaine. Grade 1 mobile posterior teeth were painful during extraction.

CONCLUSION

5% lignocaine hydrochloride gel is better than 5% bupivacaine hydrochloride gel as a topical anesthetic for extraction of grade II and grade III mobile teeth.