Cyclodextrins: improving the therapeutic response of analgesic drugs: a patent review.

INTRODUCTION: Cyclodextrins (CDs) are cyclic oligosaccharides that have recently been recognized as useful tools for optimizing the delivery of such problematic drugs. CDs can be found in at least 35 pharmaceutical products, such as anticancer agents, analgesic and anti-inflammatory drugs. Besides, several studies have demonstrated that CD-complexed drugs could provide benefits in solubility, stability and also improve pharmacological response when compared with the drug alone. AREAS COVERED: The patent search was conducted in the databases WIPO, Espacenet, USPTO, Derwent and INPI, using the keywords cyclodextrin, pain and its related terms (analgesia, hyperalgesia, hypernociception, nociception, antinociception, antinociceptive). We found 442 patents. Criteria such as the complexation of analgesic agents and evidence of improvement of the therapeutic effect were indispensable for the inclusion of the patent. So, 18 patents were selected. EXPERT OPINION: We noticed that some patents are related to the complexation of opioids, NSAIDs, as well as natural products, in different types of CDs. The use of CDs creates the prospect of developing new therapeutic options for the most effective treatment of painful conditions, allowing a reduction of dosage of analgesic drugs and the occurrence of side effects. Thus, CDs can be an important tool to improve the efficacy and pharmacological profile of analgesic drugs.

Physicochemical characterization and analgesic effect of inclusion complexes of essential oil from Hyptis pectinata L. Poit leaves with ß-cyclodextrin.

The formation of inclusion complexes of Hyptis pectinata essential oil (EOHP), with potent activities such as anti-nociceptive, anti-inflammatory, among others, with ß -cyclodextrin (ß-CD), was obtained by slurry (SC) and paste procedures (PC). The gas chromatography coupled to the mass spectrometry (GC/MS) analysis demonstrated a total of 36.4% monoterpenes and 63.6% sesquiterpenes in the EOHP. The major components of EOHP were identified as (E)- caryophyllene (54.07%). The analysis of samples (PM, PC and SC) by GC/MS involved the surface and the total extracted oils. The GC/MS results suggested important differences between in SC and PC methods indicating the complexation of mono and sesquiterpenoids in different ratios. Furthermore, the thermal analysis techniques suggests the complexation, especially in SC, which show a thermogravimetry/derivative thermogravimetry (TG/DTG) peak at 140-270ºC, probably related to oil loss. Scanning electron microscopy (SEM) images showed reduction size of the samples mainly in the SC product. Additionally, EOHP/ ß-CD improves pharmacological profile of EOHP alone in formalin-induced pain protocol in mice.

α-terpineol reduces mechanical hypernociception and inflammatory response.

α-Terpineol (TPN), a volatile monoterpene alcohol, is relatively non-toxic and one of the major components of the essential oils of various plant species. In this study, we tested for the antihypernociceptive activity of TPN (25, 50 or 100 mg/kg, i.p.) in mice using mechanical models of hypernociception induced by carrageenan (CG, 300 µg/paw) and the involvement of important mediators of its cascade signalling, such as tumour necrosis factor-α (TNF-α, 100 pg/paw), prostaglandin E2 (PGE2, 100 ng/paw) or dopamine (DA, 30 µg/paw). We also investigated the anti-inflammatory effect of TPN on the model of carrageenan-induced pleurisy and the LPS-induced nitrite production in murine macrophages. Pre-systemic treatment with TPN (25, 50 or 100 mg/kg, i.p.) inhibited the development of mechanical hypernociception induced by CG or TNF-α. A similar effect was also observed upon PGE2 and DA administration. In addition, TPN significantly inhibited the neutrophil influx in the pleurisy model. TPN (1, 10 and 100 µg/mL) also significantly reduced (p < 0.01) nitrite production in vitro. Our results provide information about the antinociceptive and anti-inflammatory properties of TPN on mechanical hypernociception and suggest that this compound might be potentially interesting in the development of new clinically relevant drugs for the management of painful and/or inflammatory disease.