Formulation factors affecting the isomerization rate of betamethasone-17-valerate in a developmental hydrophilic cream – a HPLC and microscopy based stability study

Prediction of the penetration depth of multi-lamellar liposomes in artificial skin. Application to the vectorization of corticosteroid in human skin

Our previous work showed that the size, elasticity and charge of multi-lamellar liposomes (MLLs) could not be considered separately to predict the fate of MLLs in the skin [1]. Based on this study, we developed several MLLs formulations containing a corticosteroid, betamethasone 17-valerate (B17) to transport the drug into the stratum corneum, living epidermis, dermis or through the skin. MLLs encapsulation efficiency was found to exceed 74 ± 3 % in all cases. In addition, we showed that MLLs protected the corticosteroid from thermal degradation. Comparing the penetration depth of all MLLs within artificial skin measured by Raman imaging, we established an equation for its determination, given the MLLs elasticity and size. This equation was verified experimentally on human explants: quantification of B17 in each skin layer, as well as its transdermal passage by ultra-high performance liquid chromatography, confirmed that B17 was predominantly and significantly transported in the desired layer. Eventually, we showed the benefits in using B17-loaded MLLs instead of a B17-containing pharmaceutical cream in terms of B17 penetration and thermal degradation.

The preparation and investigation of spinosin–phospholipid complex self-microemulsifying drug delivery system based on the absorption characteristics of spinosin

Objectives

The aim of this research was to investigate the intestinal absorption characteristics and mechanisms of spinosin (SPI), and a new dosage form was prepared to increase the intestinal absorption of SPI.

Methods

In this study, the intestinal absorption characteristics and mechanisms of SPI were first investigated using in situ absorption model and Caco-2 monolayer model. Subsequently, the phospholipid complex (PLC) loaded with SPI was prepared followed by a self-microemulsifying drug delivery system (SMEDDS) technique for developing a more efficient formulation.

Key findings

The results showed that the absorption rate constant (0.02 h−1) and absorption percentage (10%) of SPI were small. Paracellular and active transport pathways mainly mediated the intestinal absorption of SPI. Moreover, SPI-PLC-SMEDDS showed a nanoscale particle size and excellent dispersibility in vitro. The cellular uptake and transportation properties of SPI-PLC-SMEDDS in the Caco-2 cell model were improved significantly. Besides, a statistically dramatically higher oral bioavailability (almost fivefold) was observed following the oral administration of SPI-PLC-SMEDDS than free SPI on the basis of pharmacokinetic experiment results. Furthermore, the SPI-PLC-SMEDDS exhibited certain immunization.

Conclusions

SPI-PLC-SMEDDS could be a promising oral drug delivery system to improve the absorption of SPI.

Potential combination topical therapy of anal fissure: development, evaluation, and clinical study†

To treat anal fissure, internal anal sphincterotomy may be associated with surgical risks and incidence of incontinence. Botulinum toxin injection into the anal sphincter is invasive and expensive. Headache and hypotension hindered topical treatment with glyceryl trinitrate. Greater patient compliance, potentiated efficacy, reduced side effects, and lower cost are the major advantages offered by the combination therapy. Therefore, combination topical gels of nifedipine (NIF), lidocaine hydrochloride (LDH) and betamethasone valerate (BMV) were prepared and evaluated regarding viscosity, pH, drug content, and in vitro release. Compatibility study of drug-drug and drug-excipient mixtures preceded the formulation. Stability study was performed. A prospective randomized clinical trial was conducted for six weeks to assess the efficacy of the optimized formula in the treatment of anal fissure either acute (AAF, 37 patients) or chronic (CAF, 34 patients) in comparison with three single drug market products. The compatibility was indicated except in case of LDH with each of poloxamer 407 (P407), methylparaben, and propylparaben as well as BMV with P407. The gels showed acceptable viscosity ranges, tolerated pH values, and drugs content limits complying with the pharmacopeial limit. The gel containing 10% Transcutol^® (F2) was selected as optimized formula due to the significant (p < 0.05) enhancement in NIF release. The recommended storage temperature was 8 °C. In comparison with the market products, the optimized gel can be represented as a potential combination therapy of acute and chronic anal fissures as suggested by significantly increased healing% and significantly reduced pain, bleeding, anal discharge and itching without side effects.