Abstract
The aqueous extract ECce20 of
Cistus creticus
ssp.
eriocephalus
, herba (CCE, previously studied as
Cistus incanus
) is rich in polyphenols, including flaven-3-ols and proanthocyanidins [1]. The reported antiviral and anti-inflammatory activity of some extracts [2,3] has led us to formulate and characterise a nasal formulation for local delivery using a
CCE
hot water extract [4], supplied by the extract company Finzelberg.
Following determination of the extract's solubility in ethanol/water solvent mixes, optimised formulations containing 1, 10, 50 and 100mg/ml powdered extract and benzalkonium chloride (0.01% w/v as preservative) in ethanol/water (5:95) were developed. Solutions were delivered as an aerosol from metered dose nasal sprays (Valois VP3). Aerosols were sized by laser diffraction; the weight of each actuation was determined by difference. Solubility and delivery of
Cistus
extract was determined by absorbance at 368nm using UV Spectrophotometer.
The mean size of all aerosols was in the range 40–41µm, with a weight, per actuation, of 101.5mg. These are functions of the 100µl metered dose volume. The mean delivered dose per actuation of
CCE-
extract over the first 55 actuations of the product was 0.088±0.062mg (1mg/ml), 1.086±0.011mg (10mg/ml), 5.494±0.175mg (50mg/ml) and 11.296±0.090mg (100mg/ml).
The developed, preserved formulation has an aerosol droplet size appropriate for nasal delivery, delivers a consistent uniformity of dose (by weight) and delivers between 88 and 113% of the nominal dose of
CCE
-extract per actuation for the four concentrations of extract examined.
References:
[1] Danne, A. et al. (1993) Phytochemistry 34
:
1129–1133.
[2] Droebner, K. et al. (2007) Antivir. Res. 76:38–47.
[3] Taila, S. et al. (2008)J. Pharm. Pharmacol. 60: 62–63.
[4] Obolsky, D. (2008) Phytochemical and in vitro NF-kappa B inhibitory/Antioxidant Profiling of
Cistus creticus
L. subsp.
eriocephalus
(Viv.) Greuter & Burdet; MSc dissertation, The School of Pharmacy, University of London.