A new blend of polymeric encapsulation of azithromycin by spray-drying with a pH responsive in drug release

The microencapsulation of macrolides with polymers has been reported to retard the release of the drug in oral cavity. However, these methods are unable to control drug release in gastrointestinal tract. The aim of the present study was to investigate the effect of formulation of a new polymeric encapsulation of azithromycin which is suitable for both masking and sustained release usage. Eudragit E100 and polyethylene glycol (PEG) 4000 were chosen as the barrier coatings. The spray drying technique was used to obtain the microcapsules containing azithromycin. To obtain the initial results, the effects of several parameters were evaluated. A 3:2:1 ratio of E100:PEG 4000:azithromycin at pH 6 gave the best coating condition. Thermogravimetric analysis and IR analysis data confirmed the encapsulation of azithromycin inside polymers. The encapsulated drug was released in different rates from the particles by changing the pH (1.7 and 7.4). An analysis of the kinetic release properties indicates that the release of the drug is a combination of swelling and diffusion mechanism. The synergistic cooperation between polymers and drug due to the existence of several hydrogen bonding is supposed to influence the pH-responsive property of the encapsulated drug. Moreover, the use of mixtures of E100 and PEG 4000 appears to offer a good balance between cost and efficiency.     

Design,development and in-vitro evaluation of diclofenac taste-masked orodispersible tablet formulations

Context: Fast onset of action is prerequisite for acute pain medication. A palatable orodispersible medicine of diclofenac providing rapid analgesic effect should improve patient compliance and treatment.

Objective: In the present study, diclofenac taste-masked orodispersible tablets (ODTs) with fast release characteristics were developed. Different taste-masking approaches and formulation concepts were screened in vitro for candidate selection.

Materials and methods: Diclofenac was used as free acid. Five taste-masked microgranule formulations were prepared by wet granulation and/or coating processes, and compressed to ODTs. Citric acid (pH-modifying agent) and Eudragit® E PO (amino methacrylate copolymer) were used as taste-masking agents. Evaluation criteria were (i) disintegration time, (ii) processability and (iii) in-vitro dissolution profiles in simulated saliva (pH 7.4, 5?mL, 3?min) and compendial pH-change media (paddle, 50?rpm). The prototypes were compared to reference ODTs (without taste-masking). Most suitable ODT prototypes were selected and further evaluated for taste-masking efficiency using an electronic tongue.

Results and discussion: In simulated saliva, the drug was slower released from the prototypes (between 1.1% and 15.5%) than from reference ODTs (23.7%). Less dissolved particles are thus expected in vivo for taste perception. Two ODT prototypes showed fast and complete drug release in phosphate buffer. The formulation providing the most efficient taste-masking was selected guided by electronic tongue data.

Conclusion: A novel palatable and fast acting diclofenac ODT formulation was successfully developed. Formulation design, development and in-vitro evaluation used in this study may serve as rational approach for manufacturing taste-masked orodispersible dosage forms.     

Diclofenac fast-dissolving film: suppression of bitterness by a taste-sensing system

Context: The selection of a proper taste-masking agent (TMA) is a critical issue in the development of fast‐dissolving films containing bitter drugs. Objective: This work is aimed to evaluate the suppression of the bitter taste of a maltodextrin fast-dissolving film loaded with 13.4 mg sodium diclofenac (DS) by adding TMAs. Methods: The films were prepared by casting and drying aqueous mixtures of maltodextrin (DE = 6), glycerin, sorbitan oleate, and DS. Films were characterized in terms of thickness, tensile properties, film disintegration time, and drug dissolution time. The bitterness intensity of DS and the masking effect of TMAs were evaluated by an electronic tongue. Results: The ‘mint’ and ‘licorice’ flavors and sucralose mixture resulted appropriate to mask DS bitterness as confirmed by a panel of volunteers. The addition of these TMAs did not significantly affect the film disintegration time (15–20 seconds) and DS dissolution rate (about 5 minutes). Conclusion: The electronic tongue was allowed to discriminate the effect of the TMA also in the presence of other hydrosoluble constituents of the film. Therefore, because of its simplicity and rapidity, this technique could assist or even replace the sensory evaluation in the development of fast‐dissolving films.