Influence of ion-pairing and chemical enhancers on the transdermal delivery of meloxicam

Ex Vivo Permeation of Carprofen Vehiculated by PLGA Nanoparticles through Porcine Mucous Membranes and Ophthalmic Tissues

(1) Background: Carprofen (CP), 2-(6-chlorocarbazole) propionic acid, is used as an anti-inflammatory, analgesic and anti-pyretic agent and it belongs to the family of non-steroidal anti-inflammatory drugs (NSAIDs). CP has some adverse reactions in systemic administration; for this reason, topical administration with CP nanoparticles (CP-NPs) can be an optimal alternative. The main objective of this work is the investigation of ex vivo permeation of CP through different types of porcine mucous membranes (buccal, sublingual and vaginal) and ophthalmic tissues (cornea, sclera and conjunctiva) to compare the influence of CP-NPs formulation over a CP solution (CP-Solution). (2) Methods: The ex vivo permeation profiles were evaluated using Franz diffusion cells. Furthermore, in vivo studies were performed to verify that the formulations did not affect the cell structure and to establish the amount retained (Qr) in the tissues. (3) Results: Permeation of CP-NPs is more effective in terms of drug retention in almost all tissues (with the exception of sclera and sublingual). In vivo studies show that neither of the two formulations affects tissue structure, so both formulations are safe. (4) Conclusions: It was concluded that CP-NPs may be a useful tool for the topical treatment of local inflammation in veterinary and human medicine.

Novel skin penetrating berberine oleate complex capitalizing on hydrophobic ion pairing approach

Berberine hydrochloride (Brb) is a well-known herbal drug that holds a great promise in the recent years thanks to its various pharmacological actions. Currently, Brb is extensively researched as a natural surrogate with evidenced potentiality against numerous types of skin diseases including skin cancer. However, Brb's high aqueous solubility and limited permeability hinder its clinical topical application. In the current work, to enhance Brb's dermal availability, hydrophobic ion pairing approach was implemented combining the privileges of altering the solubility characteristics of Brb and the nanometric size that is usually gained during the ion pairing precipitation process. Sodium oleate (SO) was selected as the complexing agent due to its low toxicity and skin penetrating characteristics. Ion paired berberine oleate complex (Brb-OL) was prepared by simple precipitation technique. Brb-OL complex formation was confirmed by differential scanning calorimetry (DSC), infrared spectroscopy (IR), X-ray powder diffraction (XRD) and saturation solubility studies. It was found that Brb-OL complex formed at stoichiometric binding between oleate and Brb had an average particle size of 195.9 nm and zeta potential of -53.6 mV. The proposed Brb-OL showed 251-fold increase in saturation solubility in n-octanol which confirmed the augmented lipid solubility of the complex compared with free drug. Comparative in-vitro release study showed that Brb-OL complex had much slow and sustained release profile compared to that of free Brb. Furthermore, ex-vivo permeation study using rat skin revealed the enhanced skin permeation of ion-paired Brb-OL complex compared with free Brb. In-vivo study on healthy rats confirmed that topical application of hydrogels enriched with Brb-OL had superior skin penetration and deposition than free Brb as revealed by confocal microscope. Conclusively, ion pair formation between Brb and oleate lead to the formation of more lipophilic Brb-OL complex with nanometric particle size which is expected to be a major progressive step towards the development of a topical berberine formulation.

Ex vivo permeation of carprofen from nanoparticles: A comprehensive study through human, porcine and bovine skin as anti-inflammatory agent

The purpose of this study was the development of poly(d,l-lactide-co-glycolide) acid (PLGA) nanoparticles (NPs) for the dermal delivery of carprofen (CP). The developed nanovehicle was then lyophilized using hydroxypropyl-β-cyclodextrin (HPβCD) as cryoprotectant. The ex vivo permeation profiles were evaluated using Franz diffusion cells using three different types of skin membranes: human, porcine and bovine. Furthermore, biomechanical properties of skin (trans-epidermal water loss and skin hydration) were tested. Finally, the in vivo skin irritation and the anti-inflammatory efficacy were also assayed. Results demonstrated the achievement of NPs 187.32 nm sized with homogeneous distribution, negatively charged surface (-23.39 mV) and high CP entrapment efficiency (75.38%). Permeation studies showed similar diffusion values between human and porcine skins and higher for bovine. No signs of skin irritation were observed in rabbits. Topically applied NPs significantly decreased in vivo inflammation compared to the reference drug in a TPA-induced mouse ear edema model. Thus, it was concluded that NPs containing CP may be a useful tool for the dermal treatment of local inflammation.