Intralesional administration of recombinant collagenase API for palmar fibromatosis is performed with a sterile lyophilized single-dose presentation that is reconstituted in a diluent containing 0.3 mg/mL calcium chloride in 0.9% sodium chloride, because the zinc metalloproteinase active site requires both zinc and calcium for structural stability and catalytic activity. The approved labeling for intralesional collagenase injection specifies a per-cord dose of 0.58 mg in 0.25 mL of reconstituted solution, with the needle advanced into the palpable cord at the point of maximum deformity under local anesthesia. Aseptic handling is mandatory because the product is a sterile injectable; the finished dosage form must meet sterility testing under USP <71>, bacterial endotoxin limits under USP <85>, and particulate matter limits under USP <788> for small-volume injectables. The reconstituted solution is drawn into a single-use luer-lock syringe and administered through a small-gauge needle sufficient to permit accurate intralesional placement without penetrating tendons or neurovascular structures; after approximately 24 h, a finger extension procedure is performed to disrupt the weakened cord. The terminal product is a single-dose glass vial with a lyophilized cake, elastomeric closure, and aluminum overseal, stored at 2–8 °C and protected from light until use. In manufacturing, the API must be filled under aseptic conditions using isolator or restricted access barrier system equipment compliant with EU GMP Annex 1, and the lyophilization cycle must preserve specific activity because collapse or excessive primary drying can reduce potency.

What Limits Collagenase Activity in Intralesional Plaque Therapy for Peyronie’s Disease?

The tunica albuginea plaque in Peyronie’s disease is a dense fibrotic lesion, so intralesional injection of recombinant collagenase is limited by the need to deliver an active concentration without causing tunical rupture or vascular injury. The approved dosing schedule for collagenase injection specifies an intralesional dose of 0.58 mg in 0.25 mL per injection, with a treatment cycle comprising two injections separated by 24–72 h and a penile modeling procedure performed 24–72 h after the second injection. The needle is inserted directly into the plaque at the point of maximum curvature under local anesthesia, while avoiding the urethra, dorsal neurovascular bundle, and corpora cavernosa; this placement minimizes the risk of hematoma, penile fracture, and erectile dysfunction. The lyophilized API is reconstituted only with the supplied calcium chloride–saline diluent because the calcium concentration influences enzyme stability and substrate binding; the solution is swirled gently rather than shaken because mechanical agitation can denature the protein and reduce collagenase activity. Potency release testing for the injectable API includes a collagen substrate hydrolysis assay calibrated against a reference standard, size-exclusion chromatography for aggregates, and electrophoretic subunit profiling; the specification is established in accordance with ICH Q6B for biological activity, purity, and impurities. The terminal dosage form is a single-use vial without preservative; unused remaining solution is discarded because the diluted enzyme cannot withstand extended liquid storage or repeated needle puncture without aggregation. The approved label also imposes a maximum number of treatment cycles to avoid excessive collagenolysis of the tunica albuginea, and the safety boundaries defined in the label override any compounding variation.

Subcutaneous administration of recombinant collagenase for edematous fibrosclerotic panniculopathy uses a lyophilized vial presentation in which the API is reconstituted with a sterile calcium chloride–saline diluent, then injected into the posterior buttock fat using a multiple-site grid to disrupt collagenous septae through enzymatic subcision. The commercial presentation has a nominal 0.92 mg API per vial, and the approved injection grid divides the total dose over multiple subcutaneous injections of 0.3 mL per site to avoid deep intramuscular deposition and reduce systemic exposure. The reconstituted product is drawn into single-use luer-lock syringes and injected subcutaneously with the needle bevel up; aspiration is performed before each injection, and if blood is visible in the hub the needle is withdrawn and a fresh syringe is used to prevent intravenous administration of a proteolytic enzyme. Because the product is a sterile injectable, any handling outside the manufacturer’s original vial must occur in an ISO Class 5 environment under USP <797> compounding standards, although the approved product is intended for direct reconstitution and immediate administration without transfer to other containers. The terminal product is a single-dose vial with diluent, stored at 2–8 °C, and the reconstituted solution should not be used beyond the in-use period stated in the label because the formulation is preservative-free and susceptible to aggregation and microbial growth.

Lyophilized API Reconstitution and In-use Stability in Central Aseptic Compounding

Reconstitution of a recombinant collagenase lyophilized cake is a critical process step because the enzyme is a zinc metalloproteinase that unfolds at elevated temperature, aggregates at air-liquid interfaces, and loses activity in alkaline pH or in phosphate buffers that precipitate calcium. The lyophilized presentation typically contains a crystalline bulking agent such as mannitol or glycine and a non-reducing stabilizer such as sucrose or trehalose to maintain cake integrity at a moisture content below 3.0%; cake appearance should be white to off-white and intact, and collapsed or shrunken cake morphology signals a possible freeze-drying excursion that may prolong reconstitution time and reduce activity. After adding the diluent, the vial is swirled gently rather than shaken, and the solution is inspected visually for turbidity, fibers, and undissolved particles; the approved injectable collagenase label permits limited in-use storage, typically 1 h at room temperature or 4 h at 2–8 °C, after which the solution is discarded because diluted collagenase is not stable in liquid form and the vial contains no preservative. Manufacturing of the lyophilized API requires aseptic processing under EU GMP Annex 1 and 21 CFR Part 211; critical process parameters include primary drying chamber pressure, shelf temperature, and time above the collapse temperature, because the dried cake must remain porous enough for fast dissolution but stable enough for cold-chain distribution. Residual moisture is measured by Karl Fischer titration according to USP <921>, and potency is tested by a validated collagen substrate assay to confirm the label claim before release. The finished vial is a single-dose container with an elastomeric closure and aluminum overseal; stopper moisture vapor transmission must be controlled because moisture ingress during shelf life can lower the collapse temperature of the cake, causing collapse and loss of specific activity. In hospital pharmacies, the vial should be removed from refrigeration immediately before reconstitution, and condensation on the stopper should be avoided to reduce microbial contamination risk.

Granule-based oral dosage forms containing recombinant collagenase are an unapproved development-stage application because the enzyme is a protein that is inactivated below pH 2.0 and cleaved by pepsin and pancreatic serine proteases; any oral capsule, tablet, or granule intended for local action in the gastrointestinal tract therefore requires a gastric-resistant multiparticulate design rather than a conventional immediate-release powder blend. The most technically feasible configuration is a capsule filled with enteric-coated granules or pellets manufactured by extrusion-spheronization or fluid-bed layering onto sugar spheres; the wet mass must be processed at low temperature and short residence time because the enzyme is susceptible to shear and thermal inactivation, creating a process conflict between adequate granule densification and preservation of biological activity. The enteric coating is applied in a Wurster bed with inlet air temperature not exceeding 45 °C and product bed temperature kept below 30 °C; coating weight gain is controlled between 8% and 12% to achieve acid resistance in 0.1 N hydrochloric acid for 2 h and drug release in pH 6.8 phosphate buffer according to USP <711>. Excipient selection is restricted to non-reducing stabilizers such as trehalose, low-moisture fillers such as mannitol, and acid-neutralizing buffers that do not chelate calcium; reducing sugars, phosphate buffers, and high-shear wet granulation are unsuitable because they destabilize the enzyme or precipitate the metal cofactor. Published data for a specific recombinant collagenase oral granule formulation are limited, and regulatory acceptance would require proof of local bioactivity in the target intestinal segment rather than systemic absorption.

When a Tablet Dosage Form Is Required for a Protease API

Tableting a recombinant collagenase API is constrained by the same proteolytic and thermal limitations as oral granules, but the immediate-release tablet format introduces the additional conflict between compression force and protein stability; direct compression is therefore the only routine manufacturing route, while wet granulation is avoided because water and prolonged drying can denature the enzyme and leave an unstable amorphous residue. A direct compression blend may consist of a lyophilized or spray-dried enzyme formulation with mannitol, microcrystalline cellulose, crospovidone, and magnesium stearate; magnesium stearate levels must be kept below 1.0% to avoid excessive lubricant hydrophobicity, and blending time is minimized because shear-induced heating can aggregate the protein. Compression is performed on a rotary tablet press at low-to-moderate compression force sufficient to achieve a hardness of 40–80 N; tablets compressed above this range risk loss of tertiary structure and reduced dissolution, while tablets below this range are friable and difficult to coat. If an enteric tablet is required, the core is coated with a gastric-resistant polymer dispersion in a side-vented pan coater at a product bed temperature below 30 °C to prevent thermal inactivation; the coating process is interrupted if the bed temperature exceeds this limit, and cores are pre-dried to a moisture content below 3.0% before coating. Controlled-release oral collagenase tablets are not established as approved drug products; published data for a specific recombinant collagenase tablet configuration are limited, so formulation development must rely on enzyme activity assays, degradation product profiling, and disintegration testing under USP <701> and dissolution testing under USP <711> to confirm that tableting does not reduce the label claim below the pharmacopeial acceptance range. The finished tablets are packed in aluminum-aluminum blisters with desiccant, stored at 2–8 °C, and protected from high humidity during transit.