Iontophoretic delivery of lidocaine hydrochloride through ex-vivo human skin.

Background: Iontophoresis is one of the widely used noninvasive and painless transdermal drug delivery technique.Objective: Transdermal delivery of Lidocaine Hydrochloride using continuous and modulated iontophoresis were evaluated across human skin ex-vivo and further assessed for skin tolerance in-vivo in the Swiss albino mice.Methods: Continuous DC was modified into modulated DC by introducing ON-OFF time in continuous DC. Iontophoresis studies were conducted on human skin samples for 60 min.Results: Drug permeation of 2% lidocaine HCl was enhanced in current density-, duty cycle- and time-dependent manner across human skin. The lidocaine HCl concentration obtained with modulated DC and continuous DC iontophoresis were about three-fold and four-fold higher than passive group respectively for all current densities across human skin. Continuous DC iontophoresis was found to be more effective than modulated DC. However, no significant difference was observed in transport of lidocaine HCl between 75% and 100% (continuous) duty cycle at all current density. Further, in-vivo reversibility studies with mice confirmed that modulated iontophoresis was well tolerated by the tissue and the injury caused is transient and reversible.Conclusion: For clinical application, modulated DC iontophoresis with 75% duty cycle at 0.5 mA/cm2 current density would be recommended.

The Reliability of Polyvinylidene Fluoride Sensor for Intra- and Intersession Measurements.

A new nasal sensor has been designed using Polyvinylidene fluoride (PVDF) film using its piezoelectric property to measure nasal patency. The aim of this study is to determine the intra- and intersession reliability of the new PVDF nasal sensor measurement of unilateral and combined nasal parameters in a group of healthy subjects. Two identical nasal sensors: for right nostril (RN) and left nostril (LN) were designed using piezoelectric natured PVDF films. Twenty subjects were studied. To evaluate the repeatability, total three sets of PVDF sensor measurements were recorded, two sets were taken 5 min apart during same session without repositioning the PVDF nasal sensors and two more sets were taken during 1 h apart successively, by repositioning the PVDF nasal sensor. Intraclass correlation coefficients (ICC) of PVDF sensor measurements for intra- and intersession showed a high and greater repeatability over time for all the combined (mean) and unilateral (RN and LN) values. In both healthy and patients, ICC values for both intra- and intersession measurements were ≥ 0.80 confirming strong reliability and also almost all of the coefficients of variation for the same parameters were low (below 10%). PVDF sensor measurements showed good intra- and intersession repeatability and can be recommended for the objective monitoring of nasal patency during diagnosis and follow-up of conditions.

Effective permeation of 2.5 and 5% lidocaine hydrochloride in human skin using iontophoresis technique.

BACKGROUND: Lidocaine Hydrochloride (HCL) is one of the commonest topical local anesthetic drugs. The permeation of the lidocaine can be enhanced by iontophoresis (IOP). The purpose of this study was to evaluate the permeability of 2.5 and 5% lidocaine permeation in ex vivo human skin using different IOP waveform. METHODS: Continuous and modulated IOP at the current density of 0.5 mA/cm2 were applied across human skin (n = 3) in donor chamber of vertical diffusion cell at 2.5 and 5% lidocaine concentration. High Performance Liquid Chromatography was used to determine lidocaine concentration. RESULTS: Findings revealed that lidocaine concentration increased effectively in a time-dependent manner in both modulated and continuous IOP at 2.5 and 5% lidocaine concentration. Compared to the passive group, the flux of lidocaine with modulated and continuous IOP were higher of about six and ten-fold, respectively. However, no significant difference was observed between continuous and modulated IOP groups at both lidocaine concentrations. At 2.5% lidocaine concentration, the permeation time taken by modulated and continuous IOP to attain therapeutic levels of 142 and 164 µg/cm2 , respectively, was approximately 10 minutes. At 5% lidocaine, the therapeutic permeation of 129 and 147 µg/cm2 , respectively, was achieved at approximately 5 minutes after applying iontophoresis waveform. CONCLUSION: Study shows that modulated IOP can be a promising alternative method in clinical settings aside from continuous IOP. Based on the clinical requirements, IOP can be used at 2.5 and 5% lidocaine concentration depending on need of relatively short or very short onset action.

Evaluation of polyvinylidene fluoride nasal sensor to assess deviated nasal septum in comparision with peak nasal inspiratory flow measurements.

BACKGROUND: Deviated nasal septum (DNS) is one of the major causes of nasal obstruction. Polyvinylidene fluoride (PVDF) nasal sensor is the new technique developed to assess the nasal obstruction caused by DNS. This study evaluates the PVDF nasal sensor measurements in comparison with PEAK nasal inspiratory flow (PNIF) measurements and visual analog scale (VAS) of nasal obstruction. METHODS: Because of piezoelectric property, two PVDF nasal sensors provide output voltage signals corresponding to the right and left nostril when they are subjected to nasal airflow. The peak-to-peak amplitude of the voltage signal corresponding to nasal airflow was analyzed to assess the nasal obstruction. PVDF nasal sensor and PNIF were performed on 30 healthy subjects and 30 DNS patients. Receiver operating characteristic was used to analyze the DNS of these two methods. RESULTS: Measurements of PVDF nasal sensor strongly correlated with findings of PNIF (r = 0.67; p < 0.01) in DNS patients. A significant difference (p < 0.001) was observed between PVDF nasal sensor measurements and PNIF measurements of the DNS and the control group. A cutoff between normal and pathological of 0.51 Vp-p for PVDF nasal sensor and 120 L/min for PNIF was calculated. No significant difference in terms of sensitivity of PVDF nasal sensor and PNIF (89.7% versus 82.6%) and specificity (80.5% versus 78.8%) was calculated. CONCLUSION: The result shows that PVDF measurements closely agree with PNIF findings. Developed PVDF nasal sensor is an objective method that is simple, inexpensive, fast, and portable for determining DNS in clinical practice.

Piezoelectric sensing: Evaluation for clinical investigation of deviated nasal septum.

Noninvasive objective evaluation of nasal airflow is one of the important clinical aspects. The developed polyvinylidene fluoride (PVDF) sensor enables measurement of airflow through each side of the nose using its piezoelectric property. This study was designed to evaluate the diagnostic capability of the PVDF sensor in assessing the deviated nasal septum (DNS). PVDF nasal sensor uses its piezoelectric property to measure the peak-to-peak amplitude (Vp-p) of nasal airflow in both of the nostrils: right nostril (RN) and left nostril (LN), separately and simultaneously. We have compared the results of PVDF nasal sensor, visual analog scale (VAS), and clinician scale for 34 DNS patients and 28 healthy controls. Additionally, the results were further analyzed by receiver operating characteristic curve and correlation between PVDF nasal sensor and VAS in detecting DNS. We found a significant difference in the peak-to-peak amplitude values of the test group and the control group. The correlation between the PVDF nasal sensor measurements and VAS (RN and LN combined) for test group was statistically significant (-0.807; p < 0.001). Sensitivity and specificity of the PVDF nasal sensor measurements in the detection of DNS (RN and LN combined) was 85.3 and 74.4%, respectively, with optimum cutoff value ≤0.34 Vp-p. The developed PVDF nasal sensor is noninvasive and requires less patient efforts. The sensitivity and specificity of the PVDF nasal sensor are reliable. According to our findings, we propose that the said PVDF nasal sensor can be used as a new diagnostic tool to evaluate the DNS in routine clinical practice.