Fluid methylcellulose gel 1% EX018

Colourless translucent fluid gel. ^[1]

Base or auxiliary excipient for further compounding. Its BUD is not adopted unchanged after adding an active. ^[1]

Colourless translucent fluid gel. ^[1]

Finished-product photostability is not specified. Any required container light protection is stated under Storage. ^[1]

No oxidative stability study of the finished mixture or inert-atmosphere requirement is provided. Use the source container. ^[1]

No quantitative hydrolytic stability limit is given for this formula. Retain the prescribed water amount and quality. ^[1]

For the finished product the source specifies:
Opaque bottle, protect from moisture, <25°C. ^[1]

For the finished product the source specifies:
Opaque bottle, protect from moisture, <25°C.
Chlorhexidine digluconate: heat/alkalinity promote decomposition. ^{[1], [2]}

Chlorhexidine: check alkalinity and incompatibility with anionic ingredients. ^[2]

No complete compatibility test with added actives or alternative excipients is provided. Substitutions require separate evidence. ^[1]

Identity and weighing basis:
• Methylcellulose 1000: 1 g.
• Chlorhexidine digluconate solution 20%: 50 mg.
• Purified water: q.s. ad 100 g.
The specified chemical forms/grades belong to the exact source formula. ^[1]

Chlorhexidine: prevent eye contact; use eye protection when handling.
Clean long-sleeved laboratory clothing, hair covering and gloves during handling; change gloves after contamination or damage. ^{[2], [3], [7]}

Reference batch: 100 g. First ingredient: Methylcellulose 1000, 1 g. Independently check chemical form, units and every scale conversion before weighing.
As an intermediate, label identity and strength clearly and do not dispense as a finished medicine. Dilution or addition of an active requires new excipient, preservation and BUD calculations. Confirm release of every required base.
For the local assessment record quantity per preparation, work frequency, duration of open handling, potential exposure routes and effectiveness of controls. These are assessment inputs; no fictitious final risk score is assigned.
Release checkpoint: inspect aggregates, crystals, local texture differences and free liquid after completing the method. Record mixing geometry, batch size and actual temperatures; copying rpm to another mixer does not establish process equivalence. ^{[1], [10], [12]}

The corresponding AEMPS SOP specifies room temperature 25 ± 5°C and relative humidity ≤60%, unless the particular formula requires otherwise. This is the work environment, not processing or storage temperature.
Follow the addition sequence, temperatures and times stated under Preparation Procedure. The specific monograph is not a complete qualification of the local facility/equipment. ^{[1], [4]}

Period reported by source: 6 months under the source conditions.
This duration is a specific formulary/source instruction. This review did not verify a complete primary study establishing chemical, physical and microbiological extension for the same finished formulation.
Selected conservative general rule: up to 14 days at 2–8 °C for an aqueous form without adequately established preservation. Refrigeration must not cause precipitation, irreversible separation or other loss of suitability. If that condition fails, do not apply 14 days at room temperature; obtain specific short-use evidence.
The reference-policy ceiling in this edition is the shorter of the source period above and the general ceiling. Extension needs matching active/excipients/strength, container, temperature, a stability-indicating method and the required microbiological evidence for aqueous extension. An applicable official USP–NF compounded monograph is assessed separately in its complete text.
Use-by date = the earliest allowed date from preparation plus selected period, ingredient expiries and any shorter supported limit. In-use dating never extends overall BUD. Complete the actual date for the batch after the required checks.
A default is a conservative dating limit, not experimental proof of batch stability. Its category depends on final composition, preservation and permitted temperatures. Water percentage or loss on drying does not determine aw. Document using SOP-014/F-006; use SOP-017/F-012 for specific aw evidence.
USP does not require water-activity measurement for every nonsterile preparation. A justified classification of the actual formulation may guide dating; record it explicitly as inferred, not measured. Uncertain or borderline classification requires specific evidence or a suitable measurement. Finished-product dating does not outlast the available dating of previously compounded components/bases unless adequate specific evidence for the exact finished preparation has been formally adopted. ^{[1], [8], [9], [11], [13]}

No separately registered base is required. Any commercial vehicle remains the exact named product in the formula table. ^[1]

Balance with suitable minimum weight, mortar/pestle or homogeniser, mixing vessels, spatulas, thermometer for heated processes and volumetric equipment for mL quantities. ^[1]

Deaggregate methylcellulose. Disperse with a rod in the water/20% chlorhexidine solution mixture preheated to about 80°C as specified by the source. Allow cooling for gelation. Source specifies sieve 500. ^{[1], [4]}

The 50 mg refers to 20% chlorhexidine solution, not 50 mg active. General chlorhexidine heat sensitivity is not used to arbitrarily change this specific method. ^[1]

Opaque bottle, protect from moisture, <25°C. ^[1]

Colourless translucent fluid gel.
Additional tests from the referenced SOP:
Appearance and mass. For batches: spreadability, pH and microbiological testing RFE 5.1.4.
pH under PN/CP/001: normally test the untreated sample unless otherwise specified. Accurate measurement follows potentiometric RFE 2.2.3; strips are limited to checks not requiring high accuracy.
Spreadability PN/CP/003: fixed sample quantity between glass plates, with locally defined successive loads and times; measure two diameters and compare area against load. Temperature variation of ±0.5°C is suggested. The source gives no universal acceptance limit; establish it locally.
Record the method, acceptance criterion, actual result and reviewer separately in F-005. A critical specification failure requires quarantine and investigation under SOP-015; retesting needs justification. ^{[1], [4], [5], [6], [12]}

Source-reported conditions/container: Opaque bottle, protect from moisture, <25°C.
For the selected general ceiling: 2–8 °C, provided physical suitability and compatibility with the specific source are maintained. The 14-day rule does not apply at room temperature. ^{[1], [8], [9]}

Intermediate base for compounding. Adding an active requires reassessment of the final composition, pH, preservation and BUD. ^[1]

Fluid methylcellulose gel 1% EX018
Compounding base — not for direct administration
Quantity: ____ Batch: ____
Prepared: ____ Use by: ____
Patient / dose / frequency: ____
Storage: 2–8 °C, after confirming suitability for refrigeration.
Temperature for this batch BUD: ____ ^{[1], [8], [9]}

The numeric value is a literature reference ceiling subject to its specific conditions. No actual batch BUD has been assigned and no aw measurements have been produced. The exact formula, prerequisites, container, storage and quality evidence require approval for the actual application. The BUD clock starts when compounding begins. Use the shortest applicable supported limit and assess in-use dating separately. USP categories are a technical framework and are not presented as Greek legislation.