"ChilDrive": a technique of combining regional cutaneous hypothermia with iontophoresis for the delivery of drugs to synovial fluid

Polymer Coated Polymeric (PCP) microneedles for sampling of drugs and biomarkers from tissues

The polymer coated polymeric (PCP) microneedles were fabricated using PVP K30 in the core and ethyl cellulose in the coating. The PCP microneedles do not disintegrate in the tissue upon insertion and rather stays intact and allows diffusion of drugs and analytes across the membrane both inward and outward. In this project the potential use of PCP microneedles for sampling analytes from the dermal tissue was explored. The amount of analyte sampled depended on the concentration in the tissue, physicochemical properties of the analyte and duration of insertion of the array in the tissue. Further, an advanced type of PCP microneedle array was fabricated by entrapping absorbent beads in the core microneedles. The adsorbent enabled the PCP microneedles to recover significantly higher amount of analyte from the tissue.

Iontophoretic Mediated Intraarticular Delivery of Deformable Liposomes of Diclofenac Sodium

BACKGROUND AND OBJECTIVE

Topical therapy is ineffective in the case of Musculoskeletal Disorders (MSD) as it is not able to maintain therapeutic levels of the drug in the affected joint due to its inability to surpass the dermal circulation and penetrate into deeper tissues. One of the approaches to enhance deep tissue penetration of drugs is to increase drug delivery much above the dermal clearance. The objective of the present work was to formulate negatively charged Deformable Liposomes (DL) of Diclofenac Sodium (DS) using biosurfactants and target the same to the synovial fluid by application of iontophoresis.

METHODS

Deformable liposomes loaded with diclofenac sodium were formulated and characterized for surface morphology, particle size distribution, zeta potential and entrapment efficiency. In vitro permeation of the diclofenac from aqueous solution, conventional liposomes, and deformable liposomes under iontophoresis was performed using Franz diffusion cells and compared to passive control. Intraarticular microdialysis was carried out to determine the time course of drug concentration in the synovial fluid at the knee-joint region of the hind limb in Sprague Dawley rats.

RESULTS

The vesicles were found to display a high entrapment (> 60%) and possess a negative zeta potential lower than -30 mV. The size of the vesicles was varied from 112.41 ± 1.42 nm and 154.6 ± 3.22 nm, demonstrated good stability on the application of iontophoresis. The iontophoretic flux values for the DS aqueous solution, conventional liposomes and deformable liposomal formulation were found to be 7.55 ± 0.42, 16.75±1.77and 44.01 ± 3.47 μg/ cm² h^-1, respectively. Deformable liposomes were found to display an enhancement of 5.83 fold compared to passive control. Iontophoresis was found to enhance the availability of DS deformable liposomes (0.56 ± 0.08 μg.h/ml) in the synovial fluid by nearly 2-fold over passive delivery (0.29 ± 0.05 μg.h/ml).

CONCLUSION

Results obtained indicate that iontophoretic mediated transport of deformable liposomes could improve the regional bioavailability of diclofenac sodium to the synovial joints, an efficient mode for treating MSD in the elderly.

Manipulation of the dually thermoresponsive behavior of peptide-based vesicles through modification of collagen-like peptide domains

Materials that respond to temporally defined exogenous cues continue to be an active pursuit of research toward on-demand nanoparticle drug delivery applications, and using one or more exogenous temperature stimuli could significantly expand the application of nanoparticle-based drug delivery formulations under both hyperthermal and hypothermal conditions. Previously we have reported the development of a biocompatible and thermoresponsive elastin-b-collagen-like polypeptide (ELP-CLP) conjugate that is capable of self-assembling into vesicles and encapsulating small molecule therapeutics that can be delivered at different rates via a single temperature stimulus. Herein we report the evaluation of multiple ELP-CLP conjugates, demonstrating that the inverse transition temperature (T t) of the ELP-CLPs can be manipulated by modifying the melting temperature (T m) of the CLP domain, and that the overall hydrophilicity of the ELP-CLP conjugate also may alter the T t. Based on these design parameters, we demonstrate that the ELP-CLP sequence (VPGFG)6-(GPO)7GG can self-assemble into stable vesicles at 25°C and dissociate at elevated temperatures by means of the unfolding of the CLP domain above its T m. We also demonstrate here for the first time the ability of this ELP-CLP vesicle to dissociate via a hypothermic temperature stimulus by means of exploiting the inverse transition temperature (T t) phenomena found in ELPs. The development of design rules for manipulating the thermal properties of these bioconjugates will enable future modifications to either the ELP or CLP sequences to more finely tune the transitions of the conjugates for specific biomedical applications.

Evaluation iontophoretic delivery of a cationic ketoprofen prodrug for treating nociceptive symptoms in monosodium iodoacetate induced osteoarthritic rat model

Topical nonsteroidal anti-inflammatory drugs have been used in treatment of osteoarthritis but their efficacy is marginal. One major reason is because of limited drug direct penetration to affected joint and muscle tissues from the topical application. The main purpose of this study was to evaluate a new topical treatment through enhancing the direct drug penetration to local muscle and joint tissues for improving topical treatment of osteoarthritis. A cationic prodrug, ketoprofen choline chloride (KCC) was synthesized for iontophoretic topical delivery. Anodal iontophoretic delivery of KCC and cathodal iontophoretic delivery of ketoprofen to the knee of live hairless rats were evaluated and the drug concentrations in the joint and muscle tissues over the time were determined. In addition, a knee osteoarthritis rat model was induced with intra-articular injection of monosodium iodoacetate solution. Anodal iontophoretic delivery of KCC, cathodal iontophoretic delivery of ketoprofen, or anodal iontophoretic delivery of sodium chloride were applied to the affected knee joint of each rat group, respectively. Knee joint pain was evaluated through a hind paw weight bearing study and knee joint inflammation was evaluated through measuring of the knee diameter. Iontophoretic delivery of KCC showed much higher drug concentration in the knee joint and muscle tissues, compared to iontophoretic delivery of ketoprofen. Treatment of rat knee joint with anodal iontophoresis of KCC also showed significant pain relief and knee inflammation reduction comparing to the control group, while treatment results from cathodal iontophoresis of ketoprofen were mostly not significantly different from the control group.

Flurbiprofen concentration in soft tissues is higher after topical application than after oral administration

AIM

To compare tissue concentrations of flurbiprofen resulting from topical application and oral administration according to the regulatory approved dosing guidelines.

METHOD

Sixteen patients were included in this study. Each patient was randomly assigned to the topical application or oral administration group. In each group, a pair of tapes or a tablet, containing a total of 40 mg flurbiprofen, was administered twice at 16 and 2 h before the surgery.

RESULTS

The flurbiprofen concentration in the fat, tendon, muscle and periosteum tissues was significantly higher (P < 0.0330) after topical application (992 ng g⁻¹ [95% CI 482, 1503], 944 [95% CI 481, 1407], 492 [95% CI 248, 735], and 455 [95% CI 153, 756], respectively) than after oral administration (150 ng g⁻¹ [95% CI 84, 217], 186 [95% CI 118, 254], 82 [95% CI 49, 116],and 221 [95% CI, 135, 307], respectively).

CONCLUSION

Topical application is an effective method to deliver flurbiprofen to the human body, particularly to soft tissues near the body surface.

Single-walled carbon nanohorns as drug carriers: adsorption of prednisolone and anti-inflammatory effects on arthritis

Prednisolone (PSL), an anti-inflammatory glucocorticoid drug, was adsorbed on oxidized single-walled carbon nanohorns (oxSWNHs) in ethanol-water solvent. The quantity of adsorbed PSL on the oxSWNHs was 0.35-0.54 g/g depending on the sizes and numbers of holes on the oxSWNHs. PSL was adsorbed on both the outside and the inside of the oxSWNHs, and released quickly in a couple of hours and slowly within about one day from the respective places. The released quantity in culture medium strongly depended on the concentration of the PSL-oxSWNH complexes, suggesting that PSL adsorbing on oxSWNHs and PSL in the culture medium were in concentration equilibrium. The local injection of PSL-oxSWNHs into the tarsal joint of rats with collagen-induced arthritis (CIA) slightly retarded the progression of the arthritis compared with controls. By histological analysis of the ankle joint, the anti-inflammatory effect of PSL-oxSWNHs was also observed.

Topical preparations for pain relief: efficacy and patient adherence

There has been an increasing focus on development of new routes of drug administration to provide tailored treatments for patients, without decreasing efficacy of analgesia, in proportion to the progression of the knowledge of pain mechanisms. While acute pain acts as an alarm, chronic pain is a syndrome requiring meticulous selection of analgesic drugs of high bioavailability for long-term use. Such criteria are challenges that topical medications aim to overcome, allowing progressive delivery of active component, maintaining stable plasma levels, with a good safety profile. This review presents recent findings regarding topical formulations of the most widely used drugs for pain treatment, such as nonsteroidal anti-inflammatory agents, anesthetics, and capsaicin, and the role of physical agents as delivery enhancers (phonophoresis and iontophoresis). Although the number of topical agents is limited for use in peripheral conditions, increasing evidence supports the efficacy of these preparations in blocking nociceptive and neuropathic pain. Patient adherence to medical treatment is also a challenge, especially in chronic painful conditions. It is known that reduction of treatment complexity and pill burden are good strategies to increase patient compliance, as discussed here. However, the role of topical presentations, when compared to traditional routes, has not yet been fully explored and thus remains unclear.