Topical Gel Formulation Research Articles

Sodium lauryl sulfate increases the efficacy of a topical formulation of foscarnet against herpes simplex virus type 1 cutaneous lesions in mice.

The influence of sodium lauryl sulfate (SLS) on the efficacies of topical gel formulations of foscarnet against herpes simplex virus type 1 (HSV-1) cutaneous infection has been evaluated in mice. A single application of the gel formulation containing 3% foscarnet given 24 h postinfection exerted only a modest effect on the development of herpetic skin lesions. Of prime interest, the addition of 5% SLS to this gel formulation markedly reduced the mean lesion score. The improved efficacy of the foscarnet formulation containing SLS could be attributed to an increased penetration of the antiviral agent into the epidermis. In vitro, SLS decreased in a concentration-dependent manner the infectivities of herpesviruses for Vero cells. SLS also inhibited the HSV-1 strain F-induced cytopathic effect. Combinations of foscarnet and SLS resulted in subsynergistic to subantagonistic effects, depending on the concentration used. Foscarnet in phosphate-buffered saline decreased in a dose-dependent manner the viability of cultured human skin fibroblasts. This toxic effect was markedly decreased when foscarnet was incorporated into the polymer matrix. The presence of SLS in the gel formulations did not alter the viabilities of these cells. The use of gel formulations containing foscarnet and SLS could represent an attractive approach to the treatment of herpetic mucocutaneous lesions, especially those caused by acyclovir-resistant strains.

TOPICAL PROSTAGLANDIN E1 SEPA* GEL FOR THE TREATMENT OF ERECTILE DYSFUNCTION

Purpose We compare the systemic effects, local tolerance and effectiveness of topical gel formulations on the penis containing alprostadil (prostaglandin E1) plus 5% SEPA versus SEPA alone (placebo) in men with erectile dysfunction. Materials and Methods Erectile response, skin discomfort and erythema were measured in 48 men with erectile dysfunction secondary to vascular, neurogenic, psychogenic or mixed etiologies in this single-blind, placebo controlled trial. Results Application of prostaglandin E1 gel correlated positively with erectile response as 67 to 75% of patients had an erection compared to 17% of controls (p <0.001). Blood pressure and heart rate varied minimally. No serious adverse effects were observed in the 48 patients, although the majority had skin discomfort. Conclusions Topical prostaglandin E1 gel applied to the penis appears to be safe, and facilitates audiovisual and tactile stimulation resulting in an erection when given in a clinic setting. Consequences to the female partner remain unknown.

Topical Platelet-Derived Growth Factor for Diabetic Foot Ulcers

A topical gel formulation of recombinant human platelet-derived growth factor (becaplermin) was recently approved in the U.S. to promote healing of

Topical Delivery System for Tretinoin: Research and Clinical Implications

□ A novel topical tretinoin gel formulation containing a patented TopiCare Delivery Compound, polyolprepolymer-2 (PP-2), was shown to significantly reduce local irritation relative to a marketed tretinoin gel preparation while maintaining clinical efficacy in the treatment of acne. Several in vitro percutaneous absorption studies were conducted with 0.025% tretinoin as a model compound to determine the possible mechanism of action of PP-2 on drug delivery into and through human cadaver skin. Results of these studies have repeatedly shown that a new topical gel formulation containing PP-2 significantly reduces tretinoin penetration while potentially enhancing epidermal deposition compared with a commercial topical gel preparation at the same tretinoin concentration. These studies further support a mechanism of action whereby PP-2 serves as a retentate for drug delivery by formation of a liquid reservoir of polymer and solubilized drug on the skin surface and in the upper layers of the skin, thereby modifying delivery of tretinoin into and through skin. This reservoir of drug and polymer was established within 15min after topical application, and tretinoin was shown to be highly associated with PP-2. These in vitro findings provide a model by which a new tretinoin gel formulation containing PP-2 reduces irritation relative to a commercial tretinoin gel while maintaining clinical efficacy in the treatment of acne vulgaris.

Preparation, Characterization, and Evaluation of Liposomal Dispersions of Lidocaine

Lidocaine, a local anesthetic agent, was encapsulated into liposomes employing the conventional lipid-film hydration technique. An attempt was made to freeze dry the aqueous liposomal dispersions. The prepared liposomal dispersions were investigated by differential scanning calorimetry (DSC), transmission electron microscopy (TEM), scanning electron microscopy (SEM), 31 P-nuclear magnetic resonance (NMR) spectroscopy, and laser counting studies for characterization. The skin partition coefficient for liposomal lidocaine was calculated. The results showed that lidocaine incorporated into the liposomes got selectively partitioned and localized in the skin to a great extent. A topical liposomal gel formulation containing 2% w/w lidocaine was prepared using Carbopol-934 as the gelling agent. The prepared formulation was tested for its local anesthetic efficacy employing the pinprick test. The liposomal preparation of lidocaine gave a much longer duration of action compared to the conventional topical formulation.

In vitro percutaneous absorption of piroxicam through synthetic membranes and abdominal rat skin

The in vitro release of piroxicam from carbomer gels and its penetration through isopropyl myristate impregnated membranes and abdominal rat skin were investigated. Attempts were made to relate the differences in the release rate with physicochemical properties of the drug and the vehicle. The results showed that piroxicam is released from the topical gel formulations and diffuses through skin. It is suggested that although piroxicam flux across abdominal rat skin was lower than through isopropyl myristate membranes, this kind of membranes can be used in preliminary screening among the different piroxicam formulations.

Development and in vitro evaluation of griseofulvin gels using Franz diffusion cells

The strong antidermatophytic action of griseofulvin, following oral administration, results from its concentration in the stratum corneum. However, this route of administration is often associated with various side effects. The purpose of this work was the preparation and in vitro evaluation of several gel formulations of griseofulvin, in which the drug was dissolved, for further clinical studies as an alternative topical dosage form. The in vitro release profiles of these formulations through artificial membranes and excised human skin, determined using Franz diffusion cells, showed that griseofulvin is released from the topical gel formulations employed and diffuses through skin. Additionally, stability studies conducted under room conditions for 16 months indicated that these formulations were adequately stable. Finally, preliminary clinical studies in humans showed that griseofulvin gels were effective and also well tolerated.

Microviscosity and drug release from topical gel formulations.

Gel formulations are often used in topical drug delivery, and the drug release is controlled by two factors, the thermodynamic activity of the drug and the microviscosity of the gel. The latter property has been probed by observing the dynamic light scattering from polystyrene lattices of known particle size dispersed within Carbopol gels. The effect of gel concentration and temperature has been observed and related to the ability of the gel to release a series of salicylates.