Thermoformed blister cavities for immediate-release tablet and hard capsule formats are converted from 200–400 µm non-plasticised PVC MONO sheet on flat-bed or rotary blister lines. The PVC MONO pharma grade is formulated without monomeric plasticisers and is stabilised with calcium-zinc chemistry at 0.5–1.5 phr to satisfy the extraction limits of Ph. Eur. 3.1.11 and USP ‹661.1›. Sheet preheat is maintained at 142–152 °C; plug-assisted positive forming uses POM-C plug temperatures of 90–110 °C, plug penetration of 70–80% cavity depth, and forming air pressure of 6–8 bar. The formed cavities are sealed against aluminium lidding foil at 150–180 °C, 0.4–0.6 MPa seal pressure, and 0.5–1.5 s dwell. The terminal packaging configuration is a push-through blister pack for tablets or hard capsules with moderate moisture sensitivity; published water vapour transmission rates for 250 µm PVC MONO monolayer are typically 2.5–4.0 g/(m²·d) at 23 °C/85% RH by ASTM F1249. This configuration is not suitable for highly hygroscopic actives unless a barrier coating or cold-form aluminium laminate is selected. Corner thinning below 60 µm is rejected on automated camera inspection after forming because residual wall thickness below this value increases pinhole risk during push-through ejection.

What Limits the Plug-Assisted Forming Window for PVC MONO Tablet Blisters?

The processing window for deep cavity tablet blisters is constrained at the lower bound by insufficient sheet ductility and at the upper bound by sheet sag and uncontrolled thinning. For a 250 µm PVC MONO sheet with cavity depth-to-thickness ratios above 1.0, the acceptable forming temperature band is 142–152 °C; deviations below 138 °C generate stress whitening at the cavity corners, while deviations above 155 °C produce webbing across land areas and non-uniform flange thickness. Plug-to-cavity clearance is set at 1.8–2.2 mm for 250 µm sheet; smaller clearances produce melt fracture at the plug tip, larger clearances increase sidewall thinning. Forming dwell is limited to 0.3–0.8 s because PVC MONO dehydrochlorination accelerates when residence time at >170 °C exceeds 1.0 s; this kinetic constraint sets the upper forming temperature and the maximum cycle speed of the blister line. Ultrasonic wall-thickness mapping is used in production to verify corner thickness; rejection is triggered when measured corner thickness falls below 60 µm. Film tensile properties are characterised by ASTM D882-18 with tear initiation values below 40 N/mm used to reject off-specification sheet that will split during push-through ejection. The terminal product is a deep-drawn blister for high-diameter tablets where conventional shallow draw ratios are insufficient for tablet clearance.

For single-dose granule trays and bulk granule handling where aluminium foil is excluded to permit post-pack metal detection, 300–500 µm PVC MONO sheet is thermoformed into compartmental trays with peelable lidding. The deeper draw ratio compared with tablet blisters requires a lower plug speed and a higher plug temperature of 100–115 °C; sheet preheat is staged at 145–155 °C to compensate for additional plug contact cooling. Tray cavity depth is commonly 10–20 mm, and the flange width is retained above 6 mm to maintain peelable seal integrity. Sealing against paper/PE or PET/PE lidding is performed at 160–180 °C with 0.3–0.5 MPa pressure and 1.0–1.5 s dwell. The terminal format is a single-dose granule tray for oral reconstitution or a bulk granule storage tray for downstream capsule filling. Because PVC MONO monolayer in this gauge still exhibits measurable moisture ingress, the format is restricted to granulations with low hygroscopicity or short shelf-life assignments; moisture-sensitive formulations require the PVDC-coated variant described in the next section. Dimensional stability is checked after 24 h at 40 °C/75% RH; shrinkage above 0.5% on the cavity length axis is rejected because lidding peel force becomes inconsistent.

When PVC MONO Is Coated with PVDC for Moisture-Sensitive Granule Formulations

Aqueous polyvinylidene chloride dispersions are applied inline to corona-treated PVC MONO sheet at coating weights of 40–60 g/m². The corona pre-treatment is maintained at 38–42 mN/m; below 38 mN/m the dispersion dewets, and above 42 mN/m the PVC surface oxidises sufficiently to reduce heat-seal lacquer anchorage. The coated sheet is dried in staged ovens at 60–90 °C with total residence time of 10–20 s before winding. Moisture barrier improves from a monolayer WVTR of 2.5–4.0 g/(m²·d) to 0.8–1.2 g/(m²·d) at 23 °C/85% RH for 40 g/m² PVDC and below 0.6 g/(m²·d) for 60 g/m² PVDC, as measured by ASTM F1249. Oxygen transmission is correspondingly reduced, which is relevant for oxidation-prone granule actives. The terminal product is a high-barrier blister base used for desiccant-free packaging of hygroscopic granule-filled capsules and unit-dose granules. The process constraint is that PVDC-coated PVC MONO cannot be thermoformed at aggressive deep-draw ratios above 1.2 because the coating cracks at cavity corners; inspection for coating continuity uses dye penetration testing after forming.

Flexible PVC MONO compounds for parenteral fluid contact are formulated with plasticiser loadings of 30–40 phr, using trioctyl trimellitate or di(2-ethylhexyl) terephthalate in non-DEHP configurations, and calcium-zinc stabiliser at 0.5–1.0 phr. The compound is extruded on a single-screw line with L/D 25:1 at melt temperature 170–185 °C; the die gap is 0.4–0.8 mm and blow-up ratio is 2.0–2.5:1 for blown film. The film is cut and perimeter-welded into large-volume parenteral bags by RF welding at 27.12 MHz, with electrode pressure 4–6 bar and dwell 2–4 s. The terminal products are IV solution bags, irrigation containers, and flexible tubing segments. Compliance requires Ph. Eur. 3.1.14, USP ‹661.2›, and ISO 8536-4 for infusion sets; biological evaluation follows ISO 10993-5, ISO 10993-10, and ISO 10993-11. A known operational boundary is the sorption of lipophilic active ingredients into the plasticised PVC matrix; published data for specific API loss rates in long-term infusion configurations is limited, and this format is contraindicated for lipid-based injectable emulsions unless overpouching and short-contact administration are validated.

Injection Moulded PVC MONO Port Components and Overmoulding Constraints

Rigid PVC MONO compound with K-value 55–60 is injection moulded into luer-compatible ports, break-off closures, and rigid vial adaptors. The injection unit uses a screw with L/D 20:1 and compression ratio 2.0–2.5:1; melt temperature is held at 175–195 °C, mould temperature at 30–50 °C, injection pressure at 70–100 MPa, and back pressure at 0.5–2.0 MPa. Thermal residence time above 190 °C must remain below 3 min to avoid dehydrochlorination; the cylinder is purged with acrylic-based compound before shutdown. The terminal components are sterilised by steam or gamma radiation depending on the assembled device; dimensional stability after steam sterilisation at 121 °C for 15 min is within ±0.3% for port thread diameter when mould temperatures are held at the upper bound. Biological evaluation is performed to ISO 10993-5 and ISO 10993-10, with systemic toxicity per ISO 10993-11 and material characterisation per USP ‹87› and USP ‹88›. Overmoulding of rigid PVC MONO directly onto plasticised PVC tubing is not recommended because the differing heat histories create a weak interface; insert moulding or solvent bonding with cyclohexanone-based adhesive is preferred.

Oral liquid cap liners and induction-seal gaskets are produced from PVC MONO plastisol dispersions. The plastisol is formulated with PVC resin 100 phr, plasticiser 50–80 phr, calcium-zinc stabiliser 1–2 phr, and optional blowing agent 0.5–1.0 phr for expanded liners. The dispersion is deposited onto aluminium foil at coating thickness 0.5–1.0 mm and gelated at 180–200 °C for 60–120 s. The terminal liner is inserted into polypropylene or HDPE closures and induction-sealed to oral liquid bottles. The terminal product is the induction-seal closure liner for syrups, suspensions, and oral solutions. The liner must pass closure integrity testing under vacuum decay and methylene blue dye ingress. Compliance is assessed under FDA 21 CFR 177.1210 for closure gaskets and USP ‹661.1› for plastic material of construction. Torque retention is affected by liner compression set; gasket thickness below 0.4 mm shows elevated channel leak rates in continuous thread closures.

Thermal History Alters Stabiliser Migration Behaviour in PVC MONO Injection Components

Terminal sterilisation of plasticised PVC MONO injection components by moist heat at 121 °C for 15 min increases the total extractable load compared with non-sterilised components; the concentration increase depends on plasticiser type, film thickness, and aqueous contact medium. Published data for this specific configuration is limited, but the known degradation boundary is that PVC dehydrochlorination accelerates above 140 °C, so dry-heat sterilisation above this temperature is excluded. Extractables are profiled by liquid chromatography with UV detection and headspace gas chromatography-mass spectrometry; elemental impurities are screened under ICH Q3D and USP ‹232› with quantification by USP ‹233›. Plasticiser migration from TOTM-formulated PVC MONO into aqueous parenteral vehicles is lower than that of DEHP-formulated material under identical contact conditions; however, the replacement plasticiser must be qualified for each formulation because pH above 7.5 and solubilising vehicles can increase migration. The terminal component is a terminally sterilised PVC MONO IV bag or port assembly. The operational boundary for high-pH parenterals is pH 6.0–7.5; outside this range, extractable load increases and the container should be evaluated by extraction studies that simulate the maximum clinical contact time and temperature.