नेन्सिद्धबध्नातिषु

Operational rule vidhi

The Locative -7th case ending is not preserved before a stem ending in इन् before he word सिद्ध and before a word derived from बन्ध् .

Word by word (padaccheda)

Indeclinable न avyayaRight context इन्- सिद्धबध्नातिषु saptamī · bahuvacana

Indeclinable An avyaya such as च "and", वा "optionally", न "not".
Right context Saptamī (7th case): "when X follows", the operation applies to what precedes (1.1.66 तस्मिन्निति निर्दिष्टे पूर्वस्य). Also a condition or domain ("in the sense of").

Full reading

न इन्-सिद्धबध्नातिषु

Pāṇini leaves out words that carry over from earlier sūtras. Expand to see the rule as a reader actually understands it.

Commentary

The Locative -7th case ending is not preserved before a stem ending in इन् before he word सिद्ध and before a word derived from बन्ध् ।
Thus स्थण्डिलशायिन्, सांकाश्यसिद्धः, काम्पिल्यसिद्धः, चक्रबन्धकः, चरकबन्धकः ॥ The compounding takes place by yoga-vibhaga of sutra 2.1.40. Some use the word चक्रबन्धः as an illustration under this rule: बन्ध then is derived by अच् of 3.1.134. The बन्ध ending in घञ् is governed by 6.3.13. This sutra is an exception to 6.3.14.

Śrīśa Chandra Vasu, The Ashtadhyayi of Panini (1897), via ashtadhyayi.com.