Development of In Vivo Impedance Spectroscopy Techniques for Measurement of Micropore Formation Following Microneedle Insertion

Microneedles (MNs) provide a minimally invasive means to enhance skin permeability by creating micron-scale channels (micropores) that provide a drug delivery pathway. Adequate formation of the micropores is critical to the success of this unique drug delivery technique. The objective of the current work was to develop sensitive and reproducible impedance spectroscopy techniques to monitor micropore formation in animal models and human subjects. Hairless guinea pigs, a Yucatan miniature pig, and human volunteers were treated with 100 MN insertions per site following an overnight prehydration period. Repeated measurements were made pre- and post-MN treatment using dry and gel Ag/AgCl electrodes applied with light verses direct pressure to hold the electrode to the skin surface. Impedance measurements dropped significantly post-MN application at all sites (p < 0.05, irrespective of electrode type or gel application), confirming micropore formation. In the Yucatan pig and human subjects, gel electrodes with direct pressure yielded the lowest variability (demonstrated by lower %relative standard deviation), whereas dry electrodes with direct pressure were superior in the guinea pigs. These studies confirm that impedance measurements are suitable for use in both clinical and animal research environments to monitor the formation of new micropores that will allow for drug delivery through the impermeable skin layers.     

Diclofenac Enables Unprecedented Week-Long Microneedle-Enhanced Delivery of a Skin Impermeable Medication in Humans

Purpose

Microneedles applied to the skin create micropores, allowing transdermal drug delivery of skin-impermeable compounds. The first human study with this technique demonstrated delivery of naltrexone (an opioid antagonist) for two to three days. Rapid micropore closure, however, blunts the delivery window. Application of diclofenac (an anti-inflammatory) allows seven days of naltrexone delivery in animals. The purpose of the current work was to demonstrate delivery of naltrexone for seven days following one microneedle treatment in humans.

Methods

Human subjects were treated with microneedles, diclofenac (or placebo), and naltrexone. Impedance measurements were used as a surrogate marker to measure micropore formation, and plasma naltrexone concentrations were measured for seven days post-microneedle application.

Results

Impedance dropped significantly from baseline to post-microneedle treatment, confirming micropore formation. Naltrexone was detected for seven days in Group 1 (diclofenac + naltrexone, n?=?6), vs. 72 h in Group 2 (placebo + naltrexone, n?=?2). At study completion, a significant difference in impedance was observed between intact and microneedle-treated skin in Group 1 (confirming the presence of micropores).

Conclusion

This is the first study demonstrating week-long drug delivery after one microneedle application, which would increase patient compliance and allow delivery of therapies for chronic diseases.     

PLASMID MEDIATED DRUG RESISTANCE IN VIBRIO CHOLERAE 0139 BENGAL

Sixteen strains of Vibrio cholerae were isolated from cases of diarrhoea. Out of these, 12 (75%) were identified as Vibrio cholerae 0139 synonym Bengal and 4 (25%) as Vibrio cholerae El Tor by standard biochemical and serological tests. Modified CAMP reaction in sheep blood agar showed that 0139 produced moderate hemolysis, El Tor produced wider zone of hemolysis whereas Classical Vibrio cholerae produced no zone of hemolysis (CAMP negative). Break point minimum inhibitory concentration (MIC) by agar dilution method showed that all 0139 strains were resistant to ampicillin 8 mg/L, streptomycin 1 mg/L, chloramphenicol 8 mg/L, sulphamethoxazole 32 mg/L and trimethoprim 0.3-128 mg/L, 58.3% were sensitive to gentamicin 1 mg/L, and all were sensitive to norfloxacin 1 mg/L and cefotaxime 1 mg/L. Resistance to trimethoprim, sulphamethoxazole, ampicillin and gentamicin in 5 strains could be transferred to E coli K-12 by conjugation experiment at a rate of 5×10⁻⁶ to 4×10⁻³. Distinct plasmid bands of 35.8 mega daltons could be seen in agarose gel electrophoresis.KEY WORDS: CAMP test, Drug resistance, Plasmid, Vibrio cholerae 0139.     

Differences in the Concentrations of Small, Anionic, Antimicrobial Peptides in Bronchoalveolar Lavage Fluid and in Respiratory Epithelia of Patients with and without Cystic Fibrosis

Affinity-purified rabbit polyclonal (PAB96-1) and mouse monoclonal (1G9-1C2) antibodies to synthetic H-DDDDDDD-OH, an antimicrobial anionic peptide (AP) originally isolated from ovine pulmonary surfactant, were prepared and used to assess the concentrations of AP-like molecules in human respiratory tract samples. In bronchoalveolar lavage fluids, concentrations of AP-like molecules measured by enzyme-linked immunosorbent assay were significantly lower in 13 patients with cystic fibrosis (CF) (mean +/- standard deviation [SD], 0.78 +/- 0.46 mM) than in 34 patients without CF (1. 30 +/- 0.66 mM) (P = 0.01). In pulmonary tissues of three patients without CF, very little antigen was stained in the apical cytoplasm of the bronchial and bronchiolar epithelium yet robust staining was seen in the alveolar epithelium. In pulmonary tissues of three patients with CF, robust staining of antigen was seen in the apical cytoplasm of the bronchial and bronchiolar epithelium yet no staining was seen in the alveolar epithelium. These results show that AP-like molecules are present in healthy human respiratory tract samples and differ in concentration and location of expression in patients with and without CF.     

Retrospective Study on Efficacy of Intermaxillary Fixation Screws

Background

We evaluated the efficacy of intermaxillary fixation (IMF) screws in the treatment of mandibular fractures.

Methods

Two hundred patients with mandibular fractures, treated by IMF using these screws, were evaluated by pre and postoperative panoramic radiographs. Clinical testing was carried out for vitality and abnormal mobility of teeth adjacent to the site of screw insertions. Other factors such as possible iatrogenic dental injuries, loss, breakage or screw cover by oral mucosa and postoperative occlusion were also studied.

Result

The most important complication noticed was iatrogenic damage to dental roots.

Conclusion

Use of intraoral cortical bone screws for IMF is a valid alternative to arch bars in the treatment of mandibular fractures. Iatrogenic injury to dental roots is the commonest problem which can be minimized by an experienced surgeon.Key Words: Intermaxillary fixation, Bone screws, Mandibular fractures, Iatrogenic injury     

Mexiletine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in the treatment of arrhythmias

As a member of the class Ib antiarrhythmic drugs mexiletine's primary mechanism of action is blocking fast sodium channels, reducing the phase 0 maximal upstroke velocity of the action potential. It increases the ratio of effective refractory period to action potential duration, but has little effect on conductivity. Unlike quinidine it does not prolong QRS and QT (QTc) intervals. In the dosage range 600 to 900 mg daily mexiletine effectively suppresses premature ventricular contractions (PVCs) in 25% to 79% of patients, with or without underlying cardiac disease. In comparative studies the response rate was comparable to that with quinidine or disopyramide. However, the use of antiarrhythmic therapy in patients with asymptomatic arrhythmias is controversial. More importantly, mexiletine abolishes spontaneous or inducible ventricular tachycardia or fibrillation in the short term in 20% to 50% of patients with refractory arrhythmias. Arrhythmia suppression is maintained in 57% to over 80% of these early therapeutic successes in the long term, with mexiletine alone or in combination with another antiarrhythmic drug. As with other antiarrhythmic drugs, there is no substantial evidence that administration of mexiletine after acute myocardial infarction improves long term prognosis. Although the incidence of adverse effects associated with mexiletine is high, the majority are minor gastrointestinal or neurological effects which can be adequately controlled through dosage adjustment. Furthermore, mexiletine has minimal effects on haemodynamic variables, or on cardiac function in patients with or without pre-existing deterioration of left ventricular function, and it appears to have a low proarrhythmic potential. Thus, while the therapeutic efficacy of mexiletine for the prevention or suppression of symptomatic ventricular arrhythmias may be no greater than that of other antiarrhythmic drugs, and less than that of some (e.g. amiodarone), it is effective in a significant proportion of patients refractory to other treatments and can be administered without causing adverse haemodynamic effects to patients with complicating factors such as acute myocardial infarction or congestive heart failure.     

Cibenzoline. A review of its pharmacological properties and therapeutic potential in arrhythmias.

Cibenzoline is a class I antiarrhythmic drug with limited class III and IV activity which can be administered orally or intravenously. An elimination half-life of about 8 to 12 hours permits twice daily administration, although age and renal function must be considered when determining dosage. Cibenzoline has some activity in ventricular and supraventricular arrhythmias, including drug-refractory ventricular tachycardia or ventricular arrhythmias following recent acute myocardial infarction, although results in patients with sustained ventricular tachycardia are less promising. In comparative trials, cibenzoline has demonstrated efficacy similar to or better than that of a variety of other class I antiarrhythmic drugs and was at least as well tolerated, with a more convenient dosage schedule. However, further studies to clarify the proarrhythmic effects of cibenzoline and its use in patients with impaired left ventricular function are required, and the use of cibenzoline (and other class I antiarrhythmic agents) in patients with other than potentially lethal ventricular arrhythmias should be avoided following the results of the CAST studies. Thus, cibenzoline is an effective antiarrhythmic agent with a favourable pharmacokinetic profile that may be considered with other class I drugs in patients requiring therapy for high risk arrhythmias.     

UREAPLASMAS UREALYTICUM AND HUMAN INFERTILITY: EFFECT ON SPERMATOZOA MORPHOLOGY

Seminal fluids of 197 males with complaints of involuntary infertility were examined for spermatozoal counts, morphological changes in the spermatozoa and cultured for ureaplasmas and mycoplasmas. In 12, no spermatozoa were present, 29 had a count of less than one million and 156 had more than one million spermatozoa per mL of the seminal fluid. Various morphological changes were detected in the spermatozoa in some cases. U urealyticum and M hominis were grown in 43.15% and 16.75% in comparison to control figures of 15.9% and 11.4% respectively. There was no correlation between growth of ureaplasmas and the spermatozoal count. Among the morphological changes, presence of coiled tails, presence of a fuzzy coat around the tail and microcolonies were highly specific for culture positivity (98.2, 98.2 and 97.35% respectively) but of low sensitivity (55.2%, 14.1% and 8.2% respectively).KEY WORDS: Mycoplasma, Spermatozoa, Ureaplasma