19 research outputs found
Substantivity of sunscreens. In vitro evaluation of the transdermal permeation characteristics of some benzophenone derivatives
No full textThe in vitro permeation through excised hairless mouse skin of a series of 4-O-(N, N-dimethylaminoalkyl)-benzophenones, non-quaternarized and quaternarized, and of two commercial benzophenone sunscreens, taken as reference compounds, was investigated. The aim of the study was to verify the skin penetration of the highly skin-substantive quaternary ammonium derivatives, in comparison with their parent, non-quaternarized compounds. While the quaternary derivatives proved unable to permeate the skin during the period of observation (45 h), their parent amine hydrochlorides and the reference sunscreens (2-hydroxy-4-methoxy-benzophenone-5-sulphonic acid and 2,2′-dihydroxy-4,4′-dimethoxy-benzophenone 5,5′-sodium disulphonate), showed appreciable transdermal fluxes.
These data indicate that the presence of a quaternary ammonium group in a molecule, besides inducing a high affinity for cutaneous keratin, may result in hindered or reduced transdermal (and possibly systemic) absorption. Both features may contribute in improving the safety of a cosmetic sunscreen
Tablet for opthalmic use with controlled release of the active substance
No full textA tablet for ophthalmic use with controlled release of the active substance applicable both in the human and veterinary field. In said tablet a surface portion (a) is coated with polymer material (b) which is impermeable and/or insoluble or only slowly soluble in water, and can be further coated with bioadhesive polymer material (c). The tablet, which can be positioned in the conjunctival sac of he eye and remain there for a programmed time period, enables the number of medicament administrations to be reduced and is usable in particular for prolonged therapeutic treatment. It is furthermore described a preparation method
Pectin microspheres as ophthalmic carriers for piroxicam: evaluation in vitro and in vivo in albino rabbits
No full textApplication of the compression technique to the manufacture of pilocarpine ophthalmic inserts
No full text
Rufloxacin eyedrops: effect of different formulations on ocular pharmacokinetics in rabbits.
No full textPURPOSE: To evaluate the aqueous humor pharmacokinetics of rufloxacin in rabbits after topical administration of different formulations, and to individuate the ones showing the best pharmacokinetic profile. METHODS: Six formulations were instilled in rabbit eyes: two pH 7.2 suspensions of non-salified rufloxacin base, or zwitterion (RUF), one of which was viscosized with tamarind seed polysaccharide (TSP); two pH 7.2 solutions of RUF obtained using hydroxypropyl-beta-cyclodextrin (CD), one of which was viscosized with TSP; and two pH 5.0 solutions of rufloxacin hydrochloride (RUF-HCl ), one of which was viscosized with TSP. At different times after administration, samples of aqueous humor were withdrawn and analyzed by high-pressure liquid chromatography. The main pharmacokinetic parameters of RUF in the aqueous humor produced by the different formulations were calculated and statistical differences were assessed. RESULTS: The best results, in terms of aqueous humor bioavailability, were observed with two TSP-viscosized formulations: a solution of the hydrochloride (TSP/RUF-HCl) and a suspension of the base (TSP/RUF), followed by the non-viscosized solution of RUF-HCl. The formulations containing CD-solubilized RUF were much less effective. CONCLUSIONS: The present data confirm the significant availability-enhancing properties of tamarind seed polysaccharide, and indicate that solubilization of RUF with hydroxypropyl-beta-cyclodextrin (CD/RUF) results in decreased drug availability with respect to standard formulations. Two of the TSP-viscosized formulations (RUF suspension and RUF-HCl solution) produced aqueous humor RUF concentrations in the range of activity against Enterobacteriaceae and Pseudomonas aeruginosa, thus warranting further studies on applications of rufloxacin in ocular therapy
Relevance of polymer molecular weight to the in vitro/in vivo performances of ocular inserts based on poly(ethylene oxide)
No full textA previous study of the present authors on gel-forming erodible inserts, based on high molecular weight (MW, 400 kDa) poly(ethylene oxide) (PEO), for ocular controlled delivery of ofloxacin (OFX) has been extended to investigate the effects of PEO MW, in the 200-2000 kDa range, on insert properties relevant to therapeutic efficacy. Mucoadhesion has shown a dependence on MW, with a maximum for PEO 400. The in vitro drug release from inserts based on PEO 200, PEO 400 and PEO 900 was mainly controlled by insert erosion, whereas with PEO 2000 it was mainly diffusion-controlled in a first phase, followed by an erosion-controlled phase. The erosion time scale depended directly on MW. Immediately after application in the lower conjunctival sac of the rabbit eye, the inserts: based on PEO of whichever MW formed mucoadhesive gels, well tolerated by the animals: then the gels spread over the corneal surface and eroded. PEO 2000 was unsuitable as an insert material, since the resulting gel spilled from the eye, due to excessive swelling. The gel residence time in the precorneal area. the drug permanence time in the aqueous humor at concentrations > MIC and the time to reach the maximal drug concentration in the aqueous humor (C-max) depended directly on MW, indicating that transcorneal absorption was governed by gel erosion. All inserts increased C-max and AUG(eff) (AUC for concentrations > MIC) with respect to the commercial eyedrops. The increases caused by PEO 400 and PEO 900 were similar (3.78- and 3.16-fold, respectively, for C-max; 11.06- and 12.37-fold, respectively, for AUC(eff)), whereas smaller increases were produced by PEO 200. The PEO 400 and PEO 900 inserts have shown a potential for a topical treatment of endophthalmitis
Development and in vitro in vivo testing of mucoadhesive buccal patches releasing benzydamine and lidocaine
No full textMucoadhesive patches releasing topical drugs in the oral cavity at a slow, predetermined rate may present distinct advantages over traditional dosage forms such as mouthwashes, oral gels and lozenges. The present study was concerned with the preparation and evaluation of mucoadhesive buccal patches for controlled release of benzydamine (BNZ) and lidocaine (LDC). The drugs were used as hydrochlorides, or, to reduce their solubility and improve their release characteristics, as salts with pectin or polyacrylic acid. A LDC-tannic acid complex was also prepared and tested. After an initial screening of mucoadhesive polymers, tamarind gum (TG), a polysaccharide obtained from the seeds of Tamarindus indica, was selected as the adhesive component. In vitro tests, carried out on a cell line of human buccal epithelial origin, indicated a very low sensitivity for TG. The patches, prepared by compressing appropriate mixtures containing the drug salts/complexes, lactose and TG, were tested in vitro for mucoadhesion and drug release, and in vivo on human volunteers for retention and release of BNZ. The devices containing the salts of BNZ with pectin and polyacrylic acid, and the complex of LDC with tannic acid showed zero-order release kinetics in vitro. The patches adhered for over 8 h to the upper gums of the volunteers, and were perfectly tolerated. BNZ hydrochloride was released in vivo and in vitro with practically identical profiles
Gel-forming erodible inserts for ocular controlled delivery of ofloxacin
No full textA new application of high molecular weight (400 kDa) linear poly(ethylene oxide) (PEO) in gel-forming erodible inserts for ocular controlled delivery of ofloxacin (OFX) has been tested in vitro and in vivo. Inserts of 6 mm diameter, 20 mg weight, medicated with 0.3 mg OFX. were prepared by powder compression. The in vitro, drug release from inserts was mainly controlled by insert erosion. The erosion time scale was varied by compounding PEO with Eudragit L100 (EUD) 17%, neutralized (EUDNa17) or 71% neutralized (EUDNa71). The insert erosion rate depended on the strength of interpolymer interactions in the compounds, and on the hydrophilic-hydrophobic balance of compounds. Immediately after application in the lower conjunctival sac of the rabbit eyes. the inserts based on plain PEO, PEO-EUDNa17 or PEO-EUDNa71 formed mucoadhesive gels, well tolerated by the animals; then the gels spread over the corneal surface and eroded. The gel residence time in the precorneal area was in the order PEO-EUDNa71 MIC) were barely altered by either insert type. On the other hand, C-max, AUC(eff) and t(eff) (permanence time in the aqueous at concentrations > MIG) were strikingly increased by plain PEO inserts with respect to commercial eyedrops (5.25 +/- 0.56 vs. 1.39 +/- 0.05 mug ml(-1); 693.6 vs. 62.7 mug ml(-1) min: and 290 vs. 148 min, respectively). Bioavailability increase has been ascribed to PEO mucoadhesion and/or increased tear fluid viscosity
