In high-shear wet granulation of veterinary oral tablets, water-soluble maltodextrin veterinary grade with a dextrose equivalent of 9–12 is introduced at 5–30 wt% relative to the dry blend to act simultaneously as a soluble granulation binder and diluent. The material does not possess a pharmacologically active moiety; its function in tablet formulation is excipient-based and must be declared accordingly in regulatory submissions. Granulation end-point is controlled by impeller torque rise and wet-mass density rather than fixed time. Batch records from 300 L high-shear granulators commonly show a wet-mass temperature rise of 4–7°C and a post-granulation moisture target of 3–6% w/w before drying. The binder solution is prepared at 10–20% w/v maltodextrin in purified water and sprayed at 1.0–2.5 kg/min for a 50 kg batch. Drying in a fluid bed at inlet air temperature 60–70°C to a final loss on drying of ≤3.0% w/w is required to avoid picking during compression. Tablets compressed on a rotary press at 10–25 kN main compression force reach hardness of 50–90 N. Friability under USP <1216> remains below 0.8% when the maltodextrin fraction does not exceed 25 wt%. Disintegration time per USP <701> for uncoated tablets is 6–14 min in 37±2°C water. Dissolution per USP <711> is active-dependent but benefits from the high aqueous solubility of the matrix. One operational boundary is overgranulation: if the wet mass passes through a 1.4 mm screen and impeller power consumption exceeds the dry-blend baseline by more than 35%, the resulting granules produce tablet hardness variability greater than 15% RSD across a 100,000-tablet campaign.

What Osmolality Limits Govern Maltodextrin as a Lyophilisation Bulking Agent in Veterinary Injectables?

For freeze-dried injectable dosage forms intended for companion or production animals, water-soluble maltodextrin is evaluated when the active substance requires an amorphous glass matrix to inhibit molecular mobility during storage. The material is dissolved in Water for Injection at 5–12% w/v; solution osmolality for a 10% w/v maltodextrin solution with dextrose equivalent 9–12 is generally below 300 mOsm/kg, but the final formulation must be adjusted with sodium chloride or mannitol if isotonicity is required for small-volume parenterals. Sterile filtration through a 0.22 µm polyvinylidene fluoride membrane is performed prior to filling. Filterability testing must confirm volumetric throughput because maltodextrin solutions above 15% w/v can increase kinematic viscosity and reduce filter flux. Filling is performed in an ISO Class 5 environment under ISO 14644-1:2015. The lyophilisation cycle used in production freeze dryers with shelf area 10–20 m² includes freezing at −40°C for 3–5 h, primary drying at −20 to −10°C shelf temperature and chamber pressure 10–30 Pa for 30–48 h, and secondary drying at 20–30°C until residual moisture by Karl Fischer is ≤1.0% w/w. Published data for the collapse temperature of this precise veterinary configuration is limited; the range of approximately −15°C to −10°C is derived from carbohydrate lyophilisation platforms and should be verified by freeze-drying microscopy. Excursion beyond the collapse temperature during primary drying creates a collapsed cake with poor reconstitution. The resulting cake should dissolve in ≤2 min in sterile water for injection. Endotoxin load in the raw material must meet USP <85> and the final product must comply with USP <1> Injections and USP <790> particulate matter limits. Because maltodextrin is a carbohydrate, terminal sterilisation by moist heat may degrade the material if autoclaving exceeds 121°C for more than 15 min; aseptic filtration is therefore the preferred route for products containing this excipient.

Capsule Fill Accuracy and Moisture Drift Limits in Low-Dose Veterinary Actives

For hard gelatin or hydroxypropyl methylcellulose capsules containing low-dose active substances such as parasiticides or endocrine modifiers, water-soluble maltodextrin with dextrose equivalent 12–18 is used as a diluent in fill weights from 120 mg to 700 mg depending on capsule size. Because maltodextrin is hygroscopic, bulk powder stored above 60% relative humidity can increase moisture content from 4.0% w/w to 7.5% w/w within 24–48 h, which reduces flow and causes powder sticking to capsule tamping pins. Pre-drying at 45–50°C in a vacuum tray dryer to loss on drying ≤3.0% w/w is required before capsule filling in climates with relative humidity above 60%. The final blend is mixed in a bin blender at 15–25 rpm for 15–30 min. Blend uniformity is tested per USP <905> with a target relative standard deviation of ≤5.0% for low-dose actives. Powder flow is assessed by angle of repose and Carr index. For satisfactory automatic capsule filling on a dosator or tamping-pin machine, angle of repose should remain below 40° and Carr index below 25. Fill weight variation in a 10,000-capsule campaign is maintained within ±3.0% when the maltodextrin lot particle size D90 is controlled at ≤250 µm. Disintegration of the filled capsule per USP <701> should occur within 15 min for immediate-release veterinary capsules. If the active substance is moisture-sensitive, maltodextrin with a moisture specification ≤2.5% w/w is preferred and desiccant packaging is required.

Production of oral powders for neonatal calves, piglets, or poultry often uses water-soluble maltodextrin as a water-soluble dispersant and palatability-neutral carrier for the active substance. The powder blend is spray-dried or dry-mixed and packed in low-moisture-barrier sachets; water activity of the finished powder should be kept below 0.60 to suppress microbial growth and hydrolytic degradation. Sieve analysis of the final oral powder commonly targets a particle size range of 100–400 µm to ensure fast wetting without excessive dust. Dissolution behaviour is evaluated by adding 10 g of powder to 1 L of water at 25°C; complete dispersion should occur within 2–3 min with mild agitation. Microbial quality follows USP <2021> and USP <2022> for oral veterinary products; total aerobic microbial count is typically not more than 10³ CFU/g and total combined yeasts and moulds not more than 10² CFU/g unless the product monograph specifies otherwise. Because maltodextrin can reduce water activity but does not provide preservative efficacy, reconstituted oral solutions must be used within 24 h or preserved with approved agents if longer administration windows are required. Loss on drying by USP <921> is controlled at ≤5.0% w/w after packaging; if loss on drying exceeds 6.0% w/w, caking and sachet clumping have been observed in high-humidity distribution chains.

When Fluidised-Bed Spray Granulation Binder Feed Rates Exceed 200 mPa·s

Fluidised-bed granulation of veterinary active substances with water-soluble maltodextrin as a binder is carried out by spraying a 10–25% w/v aqueous binder solution onto the fluidised powder bed. The binder solution viscosity at 20°C remains below 200 mPa·s for maltodextrin with dextrose equivalent 12–18 at concentrations up to 25% w/v. Above this concentration or at lower dextrose equivalent values, nozzle fouling and irregular droplet formation have been recorded in production-scale top-spray units. For a 100 kg batch in a Glatt GPCG-60 type unit, spray rate is set at 0.8–2.0 kg/min, inlet air temperature at 55–70°C, product temperature at 30–40°C, and atomising air pressure at 2.0–3.5 bar. The resulting granules are dried to loss on drying ≤3.0% w/w and screened to a target range of 200–800 µm using ISO 3310-1 sieves. Granule friability is assessed by a sieve-tumbling test; acceptable granule survival after 10 min of tumbling is ≥90% w/w retained on the 250 µm sieve. Overspray, defined as a droplet size distribution with D50 above 120 µm at the nozzle, creates lumps above 1.4 mm and reduces yield below 85%. Under those conditions, reducing binder feed rate and increasing atomising air pressure restores a spray-dried droplet size D50 of 50–90 µm and yields free-flowing granules with a bulk density of 0.45–0.60 g/cm³. Compression or sachet filling of these granules is then possible for final veterinary dosage forms.

Dust-Controlled Carrier Loading for Medicated Feed Premixes in the 150–400 µm Range

Medicated feed premixes for production animals use maltodextrin as a low-dust, water-soluble carrier when the active substance is added at grams-per-tonne levels. The maltodextrin carrier fraction is first conditioned to particle size 150–400 µm, which matches the size distribution of microingredients and reduces segregation during transport. A ribbon mixer with working volume 500 L is charged with carrier and active, then mixed at 30–40 rpm for 10–15 min. The coefficient of variation of active content after mixing should be ≤5.0% when measured by sampling ten points per batch. Dusting potential is evaluated gravimetrically using a fall-tube test. Carrier loading with 1–3 wt% vegetable oil or mineral oil can reduce dusting, but oil addition may delay dissolution if the premix is subsequently used in liquid feed. The water-soluble nature of maltodextrin is an advantage in milk replacers and drinking-water medication, where insoluble carriers settle and clog nipple drinkers. Regulatory compliance for medicated feed premixes requires adherence to 21 CFR Part 558 for approved animal drugs in medicated feed and EU Regulation 2019/4 for medicated feed, with homogeneity data retained for each batch. Residual moisture of the maltodextrin carrier should be ≤5.0% w/w to prevent clumping in bulk silos.

Liquid oral drenches and syrups for sheep, cattle, swine, or companion animals incorporate water-soluble maltodextrin at 5–30% w/v to adjust body, mouthfeel, and to reduce crystallisation of actives in concentrated solutions. Viscosity of a 20% w/v maltodextrin solution with dextrose equivalent 10–15 at 20°C ranges from 4 to 12 mPa·s, which is low enough for dosing syringes but provides sufficient mouthfeel for oral administration. The carbohydrate is stable in the pH range 3.5–7.0 during typical shelf-life conditions. Prolonged exposure to pH below 3.0 at 40°C can increase reducing sugar content and initiate Maillard reactions if the active contains primary amines. Buffering with citric acid/sodium citrate systems is common when the active requires acidic pH for solubility. Clarity and absence of particulate matter are controlled by passing the finished solution through a 10 µm polypropylene filter before filling. Visual inspection is performed against a light panel. For multi-dose oral packaging, the product must comply with USP <51> antimicrobial effectiveness testing if a preservative is present; maltodextrin itself does not possess preservative action. Terminal pasteurisation at 80–85°C for 15–30 min can be applied to pH-neutral solutions, but heat-sensitive actives require aseptic filling. Specific gravity of the final liquid is 1.03–1.12, and such density is matched before filling to ensure consistent dose delivery by volume.