Control of Transdermal Permeation of Hydrocortisone Acetate from Hydrophilic and Lipophilic Formulations

The purpose of this research was the preparation of four formulations containing hydrocortisone acetate (HCA) for topical application, including two aqueous systems (hydrophilic microemulsion and aqueous gel) and two systems with dominant hydrophobicity (hydrophobic microemulsion and ointment). The formulations were tested for the release and permeation of HCA across an animal membrane. The release of HCA was found comparable for the four systems. The two microemulsions promote permeation across an ex-vivo membrane, examined by means of a Franz cell. Hydrophobic microemulsion guarantees the highest solubility (2,370 μg/ml) and flux (133 μg/cm2.h) of the drug, since it contains almost 40% Transcutol, a permeation enhancer. Gel and ointment provide lower solubility and flux, being the values, related to the ointment, the lowest ones (562 μg/ml and 0.4 μg/cm2.h). Experimental results allow the conclusion that gel and ointment can be suitable when it is desirable to minimize absorption of topically applied HCA as to keep the drug restricted to the diseased area and prevent side effects of the systemic presence of HCA

Razvoj i in vitro vrednovanje puferiranog bioadhezivnog vaginalnog gela za miješane vaginalne infekcije

An acid buffering bioadhesive vaginal (ABBV) gel was developed for the treatment of mixed vaginal infections. Different bioadhesive polymers were evaluated on the basis of their bioadhesive strength, stability and drug release properties. Bioadhesion and release studies showed that guar gum, xanthan gum and hydroxypropylmethylcellulose K4M formed a good combination of bioadhesive polymers to develop the ABBV gel. Mono sodium citrate was used as an acid buffering agent to provide acidic pH (4.4). The drugs clotrimazole (antifungal) and metronidazole (antiprotozoal as well as antibacterial) were used in the formulation along with Lactobacillus spores to treat mixed vaginal infections. The ex vivo retention study showed that the bioadhesive polymers hold the gel for 12-13 hours inside the vaginal tube. Results of the in vitro antimicrobial study indicated that the ABBV gel had better antimicrobial action than the commercial intravaginal drug delivery systems and retention was prolonged in an ex vivo retention experiment.U radu je opisan razvoj puferiranog biodhezivnog vaginalnog (acid buffering bioadhesive vaginal, ABBV) gela za terapiju miješanih vaginalnih infekcija. Ispitani su različiti bioadhezivni polimeri procijenjena su njihova bioadhezivna svojstva, stabilnost i sposobnost oslobađanja ljekovite tvari. Guar guma, ksantan guma i hidroksipropilmetilceluloza K4M tvore dobru kombinaciju za ABBV gel. Mono natrijev citrat upotrebljen je kao puferirajuća tvar koja omogućava blago kiseli pH (4,4), a kao ljekovite tvari upotrebljeni su klotrimazol (antimikotik) i metronidazol (antiprotozoik i antibakterijsko sredstvo), zajedno sa sporama Lactobacillus. Pripravci su upotrebljeni u terapiji miješanih vaginalnih infekcija. Pokusi ex vivo pokazali su da se bioadhezivni gel zadržava u vagini 12-13 sati. Rezultati in vitro ispitivanja ukazuju na to da ABBV gel ima bolje antibakterijsko djelovanje i dulje zadržavanje od intravaginalnog sustava koji je dostupan na tržištu

Bimodal release of olanzapine from lipid microspheres

Olanzapine was formulated as 10% (w/w) mixture with cutina to which stearic acid was added, ranging from 10% to 90% (w/w) of the total mass to control the drug release. The molten mixtures were processed by ultrasound-assisted spray-congealing technique, obtaining solid microspheres. The drug is stable under these conditions and only a partial miscibility in the solid state was observed by DSC between the two fatty materials with two separated melting endotherms in the thermograms: this can be due to the presence of two phases inside the solid dispersion. Olanzapine is distributed into the two phases according to its partition coefficient: two phases make the system less suitable to crystallization of the drug; the loading of the drug could reach saturation with difficulty and the rate of the olanzapine release is differentiated, since the drug is released from two different carriers. Dissolution profiles suggest occurrence of a bimodal release, where each portion of the release profile is linear and the slope increases with a higher content of stearic acid in the carrier mixture, that behaves as a release promoter. Tests were also carried out with palmitic and lauric acids for comparison and also for systems in the absence of ultrasound

MUCOADHESIVE GEL CONTAINING NAPHAZOLINE HYDROCHLORIDE FOR OPHTHALMIC DELIVERY

none6Naphazoline (NPH) is a vasoconstrictor agent, and reduces inflammation and swelling of the conjunctiva. The effect of naphazoline arises from its direct binding to adrenergic receptor sites on unstriated muscle cells in the blood vessels. A modern tendency of ocular delivery is represented by systems capable of both lengthening pre-cornea1 contact time and slowing the release of drug from the vehicle. There is considerable logic in attempting the retention of the delivery systems in the front of the eye, because of the enormous loss of an instilled drug solution that typically occurs soon after administration. In this study we present a low viscous formulation with mucoadesive properties to control the residence time in pre-corneal area and the release and permeation rates of drug.noneG.C. Ceschel; V. Bergamante; I. Orienti; G. Zuccari; C. Ronchi; A. FiniG.C. Ceschel; V. Bergamante; I. Orienti; G. Zuccari; C. Ronchi; A. Fin

MUCOADHESIVE GELS FOR BUCCAL ADMINISTRATION OF CHLORHEXIDINE DIGLUCONATE

Chlorhexidine (CHX) is a bis-bis-guanide widely used to treat skin and mucosa infections, efficient against a wide range of microbial species. The aim of this work was to design and evaluate gels containing CHX associated to mucoadhesive and swelling agents, such as CMC, HPMC, HPC and Poloxamer, to control both the residence time in the oral cavity and the release rate of the drug. Three tests were carried out to evaluate the controlled release of CHX from the gels; also the interaction polymer-mucin by means of viscosimetric measurements was tested. The same tests were also applied to a commercial formulation, Corsodyl gel® for comparison

Design and evaluation in vitro of controlled release mucoadhesive tablets containing chlorhexidine.

This investigation deals with the development of buccal tablets containing chlorhexidine (CHX), a bis-bis-guanide with antimicrobial and antiseptic effects in the oral cavity, and able to adhere to the buccal mucosa to give local controlled release of drug. A mucoadhesive formulation was designed to swell and form a gel adhering to the mucosa and controlling the drug release into the oral cavity.Some batches of tablets were developed by direct compression, containing different amounts of hydroxypropylmethylcellulose (HPMC) and carbomer; changing the amount ratio of these excipients in formulations, it is possible easily modulate the mucoadhesive effect and release of drug. The in vitro tests were performed using the USP 26/NF paddle apparatus, a specifically developed apparatus, and a modified Franz diffusion cells apparatus. This last method allows a simultaneous study of drug release rate from the tablets and drug permeation through the buccal mucosa.Similar tests have also been carried out on a commercial product, Corsodyl gel, in order to compare the drug release control of gel with respect to that of the mucoadhesive tablet, as a formulation for buccal delivery of CHX. While the commercial formulation does not appear to control the release, the formulation containing 15% w/w methocel behaves the best, ensuring the most rapid and complete release of the drug, together with a negligible absorption of the active agent as required for a local antiseptic action in the oral cavity