Microparticles, polymeric

Polymeric microparticles have been studied and developed for several years. Their contribution in the pharmacy field is of utmost importance in order to improve the efficiency of oral delivery of drugs. As drug carriers, polymer-based microparticles may avoid the early degradation of active molecules in undesirable sites of the gastrointestinal tract, mask unpleasant taste of drugs, reduce doses and side effects and improve bioavailability. Also, they allow the production of site-specific drug targeting, which consists of a suitable approach for the delivery of active molecules into desired tissues or cells in order to increase their efficiency. 

It was observed that this technique was able to produce microparticles with a mean diameter of approximately 10.17 + 3.02 pm in a reasonable to satisfactory yield depending on the formulation. This value was observed to be higher for the polymer weight ratio of 1 3 (87.00 + 4.25 %), which indicates that ESIOO improves the final result of the spray-drying process. According to the SEM analysis, the polymeric microparticles were shown to be quite similar in shape. Regardless of the formulation, they appeared to be mostly concave and asymmetric (Figure 12). 

Torchilin, V. P. (2006). Multifunctional nanocarriers. Advanced Drug Delivery Reviews, Vol. 58, 14, (December 2006), pp. (1532-1555), ISSN 0169-409X Tran, V. T., Benoit, J. P. Venier-Julienne, M. C. (2011). Why and how to prepare biodegradable, monodispersed, polymeric microparticles in the field of pharmacy International Journal of Pharmaceutics, Vol. 407,1-2, (December 2011), pp. (1-11), ISSN 0378-5173... 

In this respect, an interesting approach to reduce degradation and possible toxicity problems related to nucleic acid use in vivo is offered by their encapsulation in or association to microcarrier systems, such as neutral or cationic liposome and polymeric microparticles [41 14],... 

The question whether the intramolecularly crosslinked microparticles of non-aqueous polymer dispersions are really microgels is also justified, considering non-aqueous dispersions prepared from acrylic copolymers and melamine/formaldehyde crosslinker with particle sizes of about 300 nm. [45, 343]. In any case, these crosslinked polymeric microparticles are useful constituents of high-solids coatings, imparting a yield stress to those solutions which probably involves attractive forces between the microparticles. 

Ohagan, D. et al. (1997). Recent advances in vaccine adjuvants — the development of Mf59 emulsion and polymeric microparticles. Mol. Med. Today 3(2), 69-75. 

O Hagan DT, Ott GS, Van Nest G. Recent advances in vaccine adjuvants the development of MF59 emulsion and polymeric microparticles. Mol Med Today 1997 3 69-75. 

The precipitation of polymeric microparticles by continuous SAS techniques is described later in Chapter 9.8. The typical semi-continuous plant to which we refer in this Section is illustrated in Fig. 8.3-1. 

The possibility of controlling the morphology of the product is relevant, especially in the forms of bio-polymer preparations and controlled delivery systems. Polymeric microparticles, fibers, or three-dimensional networks can be produced by tuning the operating variables. 

Methods of preparing polymeric microparticles with tailored surface chemistries are of technological importance in a wide range of applications including drug delivery, biochemical diagnostics, and paint/coating products [34], Microparticle... 

In view of the availability of a wide variety of biocompatible and biodegradable polymers, and the ease of preparation of stable microparticles with predictable physicochemical characteristics, antibodies have been conjugated to polymeric microparticles for controlling their in vivo deposition. 

The microparticle system has become an indispensable part of the controlled drug delivery fields for the past few decades since it can readily be adapted for various administration methods. In particular, biodegradable polymeric microparticles can provide a number of advantages over conventional parenteral formulations ... 

Yeo, Y. Park, K. Control of encapsulation efficiency and initial burst in polymeric microparticle systems. Arch. Pharmacol. Res. 2004, 27 (1), 1-12. 

A technique based on the formation of a multiple emulsion with an external aqueous phase was developed for the encapsulation of water-soluble drugs in order to replace the external oil phase. Possible unwanted interactions between the oil and the emulsified wax such as swelling or dissolution of the wax, clean-up requirements of the final product, and recovery of the oil phase could be eliminated. In analogy to the encapsulation of water-soluble drugs within polymeric microparticles by a w/o/w-solvent evaporation method, a molten wax phase was used instead of an organic polmer solution. A heated aqueous solution of pseudoephedrine HCl was emulsified into the molten carnauba wax, followed by the emulsification of this w/o-emulsion into a heated external aqueous phase. The temperature of the internal and external aqueous phases had to be kept above the melting temperature of the wax in order to avoid premature... 

Table 2 Polymeric Microparticles Prepared by Using RESS ...

On the solvent-treated silicon surface, the polymeric coating is deposited selectively. Adsorption and nucleation of polymeric microparticles on the silicon surface are nonuniform. These polymer films contain cross-links with the relative high length of the molecular branches. 

---