**Author details**

156 Cellulose – Medical, Pharmaceutical and Electronic Applications

*3.2.3.1. Cellulose acetate phthalate* 

inflammatory and anti-secretory (H+ pumps inhibitors) drugs, such as diclofenac and pantoprazole sodium salts, respectively, show that these drug formulations must be coated

CAP and other agents (formaldehyde, methacrylic acid copolymer) have been used to compound delayed-release capsules of diclofenac using specific small-scale machinery or manual immersion in order to evaluate the efficiency of these enteric coating processes [32]. Capsules coated with CAP (using acetone as solvent) prepared with either small machinery or twofold manual immersion showed adequate gastro-resistance, for which the release of the drug was less than 10% in acid and greater than 75% in buffered conditions. However, the capsules coated by machinery had a poorer visual aspect than those coated by the manual process [32]. In spite of this difference, the authors did not suggest which method

A simple, quick and easily reproducible method for compounding enteric-release capsules containing diclofenac has also been described. Twenty-two batches of diclofenac sodium capsules (n=60) were divided into three groups, which were submitted to different processes of coating. A small-scale machine and an enteric coating by atomization (spraying) of organic solutions of polymers (5% CAP in a mix of acetone and alcohol) were employed for ten and six batches, respectively. Before coating, the capsules' hemi receptacles were sealed by treatment with 50% v/v hydroalcoholic solution. The dissolution test results were statistically compared inter-batch and also with reference commercial product (Voltaren® DR). Most of the batches (>75%) met the pharmacopeial requirements for enteric release, in both acid (less than 10%) and buffered (greater than 80%) conditions [33]. Results confirmed that CAP is an effective enteric coating agent in compounding practice and that the

Delayed release capsules obtained by compounding and coating with organic solutions of CAP have been evaluated for pro-drug sodium pantoprazole, a proton pump inhibitor that undergoes degradation in the acid environment of the stomach [31,84,85]. Quality control tests were performed on capsules locally acquired in compounding pharmacies. Dissolution studies for gastro-resistance evaluation were performed with granules of pantoprazole coated with CAP and encapsulated, as well as with capsules coated with CAP or other agents (formaldehyde, shellac, methacrylic acid copolymer). However, all the samples prepared by coating with CAP (capsules or granules) released their content in an acid environment and did not show adequate gastro-resistance [31]. These results reveal the need for suitable coating techniques for compounding gastro-resistant capsules, since CAP is

Cellulose and its derivatives are very important excipients in compounded medicines. Many compounded preparations containing such excipients have been investigated since 1992,

because they can irritate the stomach walls or degrade in acid environments [84,85].

was the most adequate to compound delayed-release capsules of diclofenac.

application of adequate techniques in pharmacies is important.

admittedly an effective agent for enteric coating.

**4. Conclusion** 

Flávia Dias Marques-Marinho\* and Cristina Duarte Vianna-Soares *Department of Pharmaceutical Products, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil* 
