Influence of process parameters on the preparation of pharmaceutical films by electrostatic powder deposition

Abstract

Electrostatic powder deposition (ESPD) has been developed as a solvent-free method to prepare pharmaceutical films. The aim of this work was to investigate the influence of process parameters during (1) electrostatic powder deposition, (2) curing, and (3) removal of the film from the substrate on the properties of the film. Polyethylene oxide (PEO) was used as the model polymer and stainless steel 316 as the substrate. Deposition efficiency (i.e. deposited weight) was measured with varying charging voltage, gun tip to substrate distance, and environmental humidity. Scanning electron microscopy was utilized to assess film formation, and adhesive and mechanical strength of films were measured with varying cure temperature and time. Adhesive strength was measured for films prepared on substrates of varying surface roughness. When deposition was performed at low humidity conditions, 25%RH, process parameters did not significantly affect deposition behavior. At 40%RH, increasing deposition efficiency with decreasing gun tip to substrate distance and increasing voltage (up to 60kV) was observed. Complete film formation was seen by 30min at 80°C, compared to lower curing temperatures and times. All films were readily removed from the substrates. The results show the ESPD process can be modified to produce films with good mechanical properties (e.g. tensile strength>0.06MPa), suggesting it is a promising dry powder process for preparing pharmaceutical films.

Hydroxypropyl cellulose-based orally disintegrating films of promethazine HCl for the treatment of motion sickness

“…Disintegration time of each film formulation was determined using Petri dish method [3]. A film strip of 2 x 2 cm² dimension was placed in a petri dish containing 25 mL of phosphate buffer, pH 6.8 at 37 °C and stirred.…”

“…However, in conditions like motion sickness the patient requires prompt treatment [2]. Orally disintegrating films (ODFs) of APIs have gained attention as an alternate dosage form in such cases [3]. ODFs are the thin oral strips consisting of polymeric base material, drug and other excipients [4].…”

Effect of electrode voltage for NaCl coating on baked potato chips in continuous electrostatic coating system

“…Therefore, the powder particles under electrostatic coating are more dispersed and deposited on the target when compared to nonelectrostatic coating. Several authors also found better transfer efficiency when applying electrostatic coating of seasonings on food targets [7,[11][12][13][14] .…”

“…Coating evenness shows how well food powder is dispersed on the target; therefore, it directly affects the appearance of food product and consumer acceptability [6] . High powder adhesion is also expected in the electrostatic coating because of the better attraction force of charged particles of powder on the surface of food target [7] . During processing, dust, powder build-up and overuse of food powders can be minimized by using electrostatic coating, therefore; the worker health issues and cleaning process can be reduced, resulting in lower operating costs [7,8] .…”

Dry coating of solid dosage forms: an overview of processes and applications

“…After deposition, the powder has to remain in place long enough to enable film formation by heat-induced coalescence of the individual particles. A smooth and homogeneously thick coating is achieved by reduction of the free volume, while its hardening takes place on cooling [89]. Any powder able to accumulate charge with a low decay rate is potentially suitable for being employed as an electrostatic dry coating agent [90].…”