Stable Micro Systems, a Godalming, Surrey based specialist in texture analysis and materials testing, has developed a way of evaluating the efficacy of alginate rafts.
The new "alginate raft hook" enables manufacturers accurately to quantify the characteristics of alginate gels, which are used to treat gastro-oesophageal reflux disease (GORD) or heartburn. According to the company, it will help them optimise the cohesiveness, buoyancy, volume and strength of these gels, so improving their efficacy.
Alginate reflux preparations form a neutral, insoluble floating gel layer (or raft) on top of stomach contents. This prevents gastric acid from rising into the oesophagus, which can damage the oesophageal mucosa and cause burning pain in the chest area. Alginate rafts, which commonly also contain antacids, provide rapid and long-lasting relief from these symptoms.
The efficacy of alginate rafts is heavily influenced by their physical properties, such as the types and quantities of antacids used, their ratio to the alginate dose, the acid-neutralising capability, molecular weight, concentration and viscosity.
Previous raft characterisation was often based on pH levels in and below the raft, but these tests were difficult to conduct and their results lacked accuracy. The new test method, which has been published in the International Journal of Pharmaceutics, is simple and precise and has been adopted by the British Pharmacopoeia. The sample being examined is formed around an L-shaped stainless steel wire probe held upright in a glass beaker for a period of 30min. When the raft has developed fully, the beaker is placed on the test bed of a TA.XTplus texture analyser. The wire probe is hooked onto the texture analyser's arm and pulled vertically up through the raft at a rate of 5mm/s. The force required to pull the wire probe up through the raft is recorded as the raft strength.
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