Semisolid Dosages: Ointments, Creams, and Gels

Abstract

Semisolid dosage forms are traditionally used for treating topical ailments. Various categories of drugs such as antibacterials, antifungals, and antivirals are incorporated into these products, which show their activity on the surface layers of tissues or penetrate into internal layers to reach the site of action. This article focuses on the formulation, evaluation, and regulatory features of ointments, creams, and gels.

Development of gellan gum containing formulations for transdermal drug delivery: Component evaluation and controlled drug release using temperature responsive nanogels

“…During formulation of semisolid preparations; treatments such as high-speed homogenization are used to increase mechanical shear and reduce oil droplet size to facilitate the dispersion of the components in the formulation (Chang et al, 2013;Mahalingam et al, 2007). These results suggest that formulation processing is an important element in improving transport properties of transdermal formulations (Mahalingam et al, 2007).…”

Cellulose-Derivatives-Based Hydrogels as Vehicles for Dermal and Transdermal Drug Delivery

“…In pharmaceutical applications, these hydrogels can be formulated with or without a drug substance. Medicated dermal gels can contain, in addition to the cellulose derivative as gelling agent and active substances, antimicrobial preservatives (i.e., methylparaben and propylparaben, or chlorhexidinegluconate), stabilizers (i.e., edetate disodium), dispersing agents (i.e., alcohol and/or glycerol, propyleneglycol, sorbitol), and permeation enhancers [95][96][97][98]. Minimum gel-forming concentrations of cellulose derivatives are different, based on the type and the molecular weights of these derivatives, but the medium range is about 4-6% (w/v), as mentioned before ( Table 8).…”

“…Syneresis, a commonly observed phenomenon of physical instability of these hydrogels, can be determined by water loss from the gel network after a heating-cooling cycle. In the case of medicated cellulose derivatives hydrogels, the chemical stability of active substances into the gel is evaluated by accelerated aging studies, which use different analytical methods to evidence the possible drug degradation in the hydrogel, under extreme conditions of temperature, moisture and light [95].…”

“…In large scale production of pharmaceutical cellulose derivatives hydrogels, different mills, separators, mixers, deaerators, and shifters are used. Figure 2 present two different processing machines for the hydrogels preparation: a single mixing kettle equipment with slow agitation to avoid air entrapment (a) and "one bowl" vacuum processing machine (b) which is designed to control the processing temperature, and to mix (using a counterrotating mixing system), homogenize (using a high-shear rotor/stator system) and remove the entrapped air (during the product recirculation) [95,98].…”

“…Further removal of air bubbles by different methods including long -term standing, low -temperature storage, sonication, or inclusion of silicon antifoaming agents is commonly used. In addition, in large scale production vacuum vessel deaerators are used to remove the entrapped air [95,[97][98][99]. Figure 1 shows the flow chart of the fabrication process of a cellulose derivative hydrogel.…”