Formulation and evaluation of selected transmucosal dosage forms containing a double fixed-dose of acyclovir and ketoconazole

[Antiviral activity of the organic germanium complex with aciclovir against herpes simplex virus (Herpesviridae: Alphaherpesvirinae: Simplexvirus: Human alphaherpesvirus 1/2) in the in vitro and in vivo systems]

INTRODUCTION

A significant increase in the incidence of various forms of herpesvirus infection (HVI) determines the need to search for new approaches to the modification of one of the basic antiviral drugs aciclovir (ACV) and its dosage forms to improve their biopharmaceutical characteristics and increase the effectiveness of therapy. In this aspect, an innovative organic germanium complex with aciclovir (OGCA) is promising.The aim of the study was to assess the antiviral activity of OGCA against the herpes simplex virus (HSV) (human herpes virus, HHV) on the HVI models both in vitro and in vivo.

MATERIAL AND METHODS

We studied the activity of OGCA in a therapeutic regimen against HSV-1 (HHV-1) (Kl strain), HSV-2 (HHV-2) (VN strain) using virological and statistical research methods in the in vitro model of HVI on Vero cell culture and the model of genital herpes (GH) caused by HHV-2 (VN strain) in male guinea pigs (Canis porcellus).

RESULTS AND DISCUSSION

It was found OGCA inhibits the replication of HHV-1 and HHV-2 in Vero cells, and has anti-HHV activity in the GH model in male guinea pigs, leading to a decrease in the severity and duration of the disease, the intensity and duration of viral shedding. The most pronounced activity was detected when preparation was applied topically 5 times a day for 5 days at the early stages of infection (3% gel). The delayed use of OGCA (48 hours after infection) also had statistically significant efficacy compared to commercial reference drugs containing aciclovir or its pro-drugs: aciclovir (5% cream), AIL (acyclovir+interferon alfa-2b+lidocaine, 3% ointment), penciclovir (1% cream). OGCA significantly reduced the number of days of the pathogen shedding, as well as its infectivity, compared to animals in the control group and ones receiving placebo. The activity of OGCA, apparently, is due to its improved biopharmaceutical characteristics compared to aciclovir, as well as the presence of a number of biological activities of its constituent components.

CONCLUSION

The results of the study allow us to consider OGCA as the basis for the development of antiviral agents for the treatment of HVI.

Identification of critical formulation parameters affecting the in vitro release, permeation, and rheological properties of the acyclovir topical cream

To understand effects of formulation variables on the critical quality attributes (CQA) of acyclovir topical cream, this study investigated effects of propylene glycol (PG), poloxamer, and sodium lauryl sulfate (SLS) concentrations, acyclovir particle size, and formulation pH of the acyclovir cream. Fifteen formulations were prepared and characterized for rheological properties, particle size distribution, drug release and in vitro skin permeation. Drug distribution between various phases of the cream was determined. The concentration of soluble acyclovir in the aqueous phase was determined as a surrogate of the equilibrium with other acyclovir species in the cream. The interaction among effects of the formulation variables on the amount of acyclovir retained by skin was also evaluated. The results showed that PG significantly (p < 0.05) increased the yield stress, viscosity, drug concentration in the aqueous phase, and drug release. The PG and SLS significantly (p < 0.05) increased acyclovir retention by skin samples. Particle size of acyclovir inversely affected the drug release. This study revealed that the employed concentrations of PG and SLS and particle size of the dispersed acyclovir are critical formulation variables that should be carefully controlled when developing acyclovir topical creams with desired performance characteristics.

Development of Topical/Transdermal Self-Emulsifying Drug Delivery Systems, Not as Simple as Expected

Self-emulsifying drug delivery systems (SEDDSs) originated as an oral lipid-based drug delivery system with the sole purpose of improving delivery of highly lipophilic drugs. However, the revolutionary drug delivery possibilities presented by these uniquely simplified systems in terms of muco-adhesiveness and zeta-potential changing capacity lead the way forward to ground-breaking research. Contrarily, SEDDSs destined for topical/transdermal drug delivery have received limited attention. Therefore, this review is focused at utilising principles, established during development of oral SEDDSs, and tailoring them to fit evaluation strategies for an optimised topical/transdermal drug delivery vehicle. This includes a detailed discussion of how the authentic pseudo-ternary phase diagram is employed to predict phase behaviour to find the self-emulsification region most suitable for formulating topical/transdermal SEDDSs. Additionally, special attention is given to the manner of characterising oral SEDDSs compared to topical/transdermal SEDDSs, since absorption within the gastrointestinal tract and the multi-layered nature of the skin are two completely diverse drug delivery territories. Despite the advantages of the topical/transdermal drug administration route, certain challenges such as the relatively undiscovered field of skin metabolomics as well as the obstacles of choosing excipients wisely to establish skin penetration enhancement might prevail. Therefore, development of topical/transdermal SEDDSs might be more complicated than expected.